Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent material...Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent materials were successfully synthesized by loading TEPA onto the pore MgO/ZrO_(2)carriers in the paper.The pore structure and surface characteristic of the samples were analyzed by using XRD,BET,FT-IR and SEM.The adsorbent materials exhibited microcrystalline state,and the crystallinity of all samples gradually decreased as the increase of TEPA content.The pore structure analysis indicated that the modification of MgO-ZrO_(2)adsorbents with TEPA led to the decrease of the specific surface areas,but the narrow micro-mesopore size distributions ranging from 1.8-12 nm in the adsorbents still were maintained.FT-IR spectrum results further verified the successful loading of TEPA.The adsorption capacity of the adsorbents for CO_(2)were tested by using an adsorption apparatus equipped with gas chromatography.The results indicated that when the TEPA loading reached 50%,the sample exhibited the maximum adsorption value for CO_(2),reaching 4.07 mmol/g under the operation condition of 75℃and atmospheric pressure.This result could be assigned to not only the base active sites but also the coexistence of both micropore and mesopore in the adsorbent.After three cycles tests for CO_(2)capture,the adsorption value of the sample for CO_(2)can also reached 95%of its original adsorption capacity,which verified the excellent cyclic operation stability.展开更多
Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,...Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.展开更多
Conventional powder/pellet-based systems used for mitigating the environmental challenges posed by CO_(2)emissions present inefficiencies in mass/heat transfer,pressure drop,and clogging.Monolithic adsorption material...Conventional powder/pellet-based systems used for mitigating the environmental challenges posed by CO_(2)emissions present inefficiencies in mass/heat transfer,pressure drop,and clogging.Monolithic adsorption materials have emerged as a promising alternative to such systems.Additive manufacturing(AM)enables precise structural optimization and active component control in monolithic adsorbents,enhancing the adsorption kinetics while minimizing mechanical wear.This review examines the progress in AM-driven CO_(2)adsorbent development,covering the following aspects:(1)fabrication techniques for monolithic adsorbents and key metrics for evaluating their mechanical and adsorption properties,(2)applications of AM methods(extrusion,coating,gel spinning,and 3D printing)under fixed-source and direct-air capture scenarios,and(3)integrated systems combining CO_(2)adsorption and conversion.However,balancing adsorption performance with mechanical strength is a critical challenge.The trade-off can be addressed through advanced AM strategies such as hybrid material architectures and computational design.Future advancements will hinge on hybrid AM techniques to decouple structural and functional demands,AI/ML-driven multi-objective optimization for pore structure refinement and stress distribution,and lifecycle sustainability analytics to reduce energy use and material waste.By synergizing these approaches,next-generation monolithic adsorbents can achieve high capacity,mechanical robustness,and cost-effectiveness,positioning AM as a scalable and sustainable platform for carbon capture technologies.展开更多
Although supported solid amine adsorbents have attracted great attention for CO_(2) capture,critical chemical deactivation problems including oxidative degradation and urea formation have severely restricted their pra...Although supported solid amine adsorbents have attracted great attention for CO_(2) capture,critical chemical deactivation problems including oxidative degradation and urea formation have severely restricted their practical applications for flue gas CO_(2) capture.In this work,we reveal that the nature of surface hydroxyl groups(metal hydroxyl Al–OH and nonmetal hydroxyl Si–OH)plays a key role in the deactivation mechanisms.The polyethyleneimine(PEI)supported on Al–OH-containing substrates suffers from severe oxidative degradation during the CO_(2) capture step due to the breakage of amine-support hydrogen bonding networks,but exhibits an excellent anti-urea formation feature by preventing dehydration of carbamate products under a pure CO_(2) regeneration atmosphere.In contrast,PEI supported on Si–OHcontaining substrates exhibits excellent anti-oxidative stability under simulated flue gas conditions by forming a robust hydrogen bonding protective network with Si–OH,but suffers from obvious urea formation during the pure CO_(2) regeneration step.We also reveal that the urea formation problem for PEI-SBA-15 can be avoided by the incorporation of an OH-containing PEG additive.Based on the intrinsic understanding of degradation mechanisms,we successfully synthesized an adsorbent 40PEI-20PEG-SBA-15 that demonstrates outstanding stability and retention of a high CO_(2) capacity of 2.45 mmol g^(−1) over 1000 adsorption–desorption cycles,together with negligible capacity loss during aging in simulated flue gas(10%CO_(2)+5%O_(2)+3%H_(2)O)for one month at 60–70℃.We believe this work makes great contribution to the advancement in the field of ultra-stable solid amine-based CO_(2) capture materials.展开更多
Desulfurization technology is rather difficult and urgently needed for carbon dioxide(CO_(2))utilization in industry.A new Cu(I)-based adsorbent was synthesized and examined for the capacity of removing carbonyl sulfi...Desulfurization technology is rather difficult and urgently needed for carbon dioxide(CO_(2))utilization in industry.A new Cu(I)-based adsorbent was synthesized and examined for the capacity of removing carbonyl sulfide(COS)from a CO_(2)stream in an effort to solve the competitive adsorption between CO_(2)and COS and to seek opportunity to advance adsorption capacity.A wide range of character-ization techniques were used to investigate the physicochemical properties of the synthesized Cu(I)adsorbent featuringπ-complexation and their correlations with the adsorption performance.Meanwhile,the first principal calculation software CP2K was used to develop an understanding of the adsorption mechanism,which can offer useful guidance for the adsorbent regeneration.The synthesized Cu(I)adsorbent,prepared by using copper citrate and citric acid on the ZSM-5(SiO_(2)/Al_(2)O_(3)=25)carrier,outperformed other adsorbents with varying formulations and carriers in adsorption capacities.Through optimization of the preparation and adsorption conditions for various adsorbents,the breakthrough adsorption capacity(Qb)for COS was further enhanced from 2.19 mg/g to 15.36 mg/g.The formed stableπ-complex bonds between COS and Cu(I),as confirmed by density func-tional theory calculations,were verified by the significant improvement in the adsorption capacity after regeneration at 600°C.The above advantages render the novel synthesized Cu(I)adsorbent a promising candidate featuring cost-effectiveness,high efficacy and good regenerability for desulfurization from a CO_(2)stream.展开更多
This study introduced a microwave-assisted pyrolysis method for the rapid and efficientpreparation of boron-doped porous biochar. The resulting biochar exhibited a large specificsurface area (933.39 m^(2)/g), a rich p...This study introduced a microwave-assisted pyrolysis method for the rapid and efficientpreparation of boron-doped porous biochar. The resulting biochar exhibited a large specificsurface area (933.39 m^(2)/g), a rich porous structure (1.044 cm3/g), and abundant active sites.Consequently, the prepared boron-doped porous biochar exhibited higher efficiency in adsorbingtetracycline with a maximum adsorption capacity of 413.223 mg/g, which significantlyexceeded that of unmodified biochar andmost commercial and reported adsorbents.The correlation analysis between the adsorption capacity and adsorbent characteristics revealedthat the formation of the –BCO_(2) group enhanced π–π electron donor–acceptor interactionsbetween boron-doped porous biochar and tetracycline. This mechanism mainlycontributed to the enhanced adsorption of tetracycline by boron-doped porous biochar. Additionally,the as-prepared boron-doped porous biochar exhibited broad applications in removingantibiotics (tetracycline), phenolics (bisphenol A), and dyes (methylene blue andrhodamine B). Moreover, the boron-doped porous biochar exhibited satisfactory stability,and its adsorption capacity can be nearly completely regenerated through simple heat treatment.This study provides new insights into the effectiveness of boron-doped carbonaceousmaterials in removing antibiotic contaminants.展开更多
Sodium-based adsorbents(Na_(2)CO_(3)/γ-Al_(2)O_(3))exhibit significant potential for commercial utilization in CO_(2)capture.Nevertheless,the requirement for high desorption temperatures poses challenges in terms of ...Sodium-based adsorbents(Na_(2)CO_(3)/γ-Al_(2)O_(3))exhibit significant potential for commercial utilization in CO_(2)capture.Nevertheless,the requirement for high desorption temperatures poses challenges in terms of the high-quality heat needed for desorption.This study integrated ZrO_(2)doping into a sodium-based adsorbent to enhance its CO_(2)capture performance and lower its desorption temperature.The research investigated the CO_(2)adsorption capacity,reaction rate,and desorption characteristics of the ZrO_(2)-doped Na_(2)CO_(3)/γ-Al_(2)O_(3)adsorbents in detail.Additionally,the catalytic mechanism of ZrO_(2)was elucidated through Density Functional Theory calculations.The results showed that ZrO_(2)doping increased the adsorption rate and capacity of the adsorbent and reduced the desorption energy consumption.Desorption reaction activation energy reduced to 44.8 kJ/mol.The adsorbent doped with 3wt.%ZrO_(2)demonstrated the highest adsorption capacity and rate under optimal conditions,with a reaction temperature of 45℃,an adsorption capacity of 1.66 mmol/g,and a carbon conversion rate of 80.2%.ZrO_(2)acted as a catalyst,enhancing CO_(2)and H_(2)O adsorption,and facilitated CO_(2)desorption in the sodium-based adsorbent by forming[ZrO(OH)]^(+)and OH^(−)through H_(2)O adsorption activation.The lower energy barrier(0.17 eV)for the dissociative adsorption pathway of H_(2)O molecules on the ZrO_(2)surface further supported the role of ZrO_(2)in enhancing the overall adsorption performance of the adsorbent in the carbon capture process.Ultimately,the ZrO_(2)-doped Na_(2)CO_(3)/γ-Al_(2)O_(3)adsorbent was identified as having low desorption energy consumption,high adsorption capacity,and rate,offering potential cost reductions in CO_(2)capture and representing a promising adsorbent for this application.展开更多
H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ ...H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ extracted.The effects of lithium titanium ratio,calcining temperature and time were investigated on the synthesis of Li2TiO3.Li2TiO3,H2TiO3 and the adsorbed Li＋ adsorbent were characterized by XRD and SEM.The lithium adsorption properties were investigated by the adsorption kinetics and adsorption isotherm.The results indicate that H2TiO3 has an excellent adsorptive capacity for Li＋.Two simplified kinetic models including the pseudo-first-order and pseudo-second-order equations were selected to follow the adsorption processes.The rate constants of adsorption for these kinetic models were calculated.The results show that the adsorption process can be described by the pseudo-second-order equation,and the process is proved to be a chemical adsorption.The adsorption process that H2TiO3 adsorbs Li＋ in LiCl solution well fits the Langmuir equation with monolayer adsorption.展开更多
Characteristics of 13x molecular sieve, silica gel and DH 5 and DH 7 prepared by authors, were investigated for the solid desiccant cooling system. The adsorption isotherms of DH 5 and DH 7 were experimentally det...Characteristics of 13x molecular sieve, silica gel and DH 5 and DH 7 prepared by authors, were investigated for the solid desiccant cooling system. The adsorption isotherms of DH 5 and DH 7 were experimentally determined. The performance parameters of adsorption capacity, air humidity, regeneration temperature and cooling volume were tested and discussed in detail. The results show that the properties of new adsorbents DH 5 and DH 7 on desiccant cooling are much better than those of common desiccants. The maximum adsorption volumes of water on DH 5 and DH 7 are 0.72?kg/kg and 0.73 ?kg/kg, respectively. The desiccant cooling volumes of DH 7and DH 5 are 2.2 and 1.3 times larger than those of silica gel and 13x(molecular sieve), respectively, after regeneration at 100?℃. The cooling volume per mass unit of DH 5 is 1.9 times larger that of 13x.展开更多
A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) w...A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.展开更多
According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters...According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters including the total yield, adsorption of methylene blue, adsorption of iodine, BET surface area, micro-pore volume are 35%—49%, 16.5—38 mg/g, 285—362 mg/g, 185—359 m2/g, and 0.112—0.224 m3/g, respectively. According to the experimental data, the multi-linear regression method was adopted to fit the relations between the characteristic parameters and influential factors. At final, through optimization method, the optimal adsorbent is obtained when using 62 min as hold time and 1105K as pyrolysis temperature. Under the conditions, the adsorbent was produced and compared the characteristic parameters with model forecast value, the coherence is satisfied.展开更多
It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic r...It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH ? 2–12, which can imply its universal utilization. The prepared BiFeO_3/Carbon nanocomposites have also displayed excellent capacities(over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO_3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO_3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.展开更多
Adsorption is one of the most effective technologies in the treatment of colored matter containing wastewater. Graphene related composites display potential to be an effective adsorbent. However, the adsorption mechan...Adsorption is one of the most effective technologies in the treatment of colored matter containing wastewater. Graphene related composites display potential to be an effective adsorbent. However, the adsorption mechanism and their regeneration approach are still demanding more efforts. An effective magnetically separable absorbent, Fe3O4 and reduced graphene oxide(RGO) composite has been prepared by an in situ coprecipitation and reduction method. According to the characterizations of TEM, XRD, XPS, Raman spectra and BET analyses, Fe3O4 nanoparticles in sizes of 10-20 nm are well dispersed over the RGO nanosheets, resulting in a highest specific area of 296.2 m2/g. The rhodamine B adsorption mechanism on the composites was investigated by the adsorption kinetics and isotherms. The isotherms are fitting better by Langmuir model, and the adsorption kinetic rates depend much on the chemical components of RGO. Compared to active carbon, the composite shows 3.7 times higher adsorption capacity and thirty times faster adsorption rates. Furthermore,with Fe3O4 nanoparticles as the in situ catalysts, the adsorption performance of composites can be restored by carrying out a Fenton-like reaction, which could be a promising regeneration way for the adsorbents in the organic pollutant removal of wastewater.展开更多
Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specifi...Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specific surface area,h-BN-related nanostructures exhibit appealing adsorption propertiewhich can be widely applied for separation and purification towards energy and environment treatmenIn this review,recent progress in designing h-BN micro,nano-structure,controlled synthesis,performancoptimizing as well as energy and environment-related adsorption applications are summarized.Strategieto tailor the h-BN can be classified as morphology control,element doping,defect control and surfacmodification,focusing on how to optimize the adsorption performance.In order to insight the intrinsimechanism of tuning strategies for property optimization,the significant adsorption applications of h-Btowards hydrogen storage,CO2 capture,pollutants removal from water and adsorption desulfurization arpresented.展开更多
The carbonaceous adsorbent was prepared from mixtures of dewatered sludge and sawdust with enhanced ZnCl2 chemical activation.Characteristics of the adsorbent were studied using scanning electron microscope(SEM) ,Four...The carbonaceous adsorbent was prepared from mixtures of dewatered sludge and sawdust with enhanced ZnCl2 chemical activation.Characteristics of the adsorbent were studied using scanning electron microscope(SEM) ,Fourier transform infrared spectroscopy(FT-IR) ,and adsorption of nitrogen.The surface analysis showed that the carbonaceous adsorbent had good specific surface and porosity(394 m 2 ·g-1of BET surface,0.12 and 0.10 ml·g-1of microporous and mesoporous volume,respectively) .The oxygen functional groups such as OH,C O and C O were found on the surface by FTIR and XPS(X-ray photoelectron spectroscopy) .The adsorption of elemental mercury(Hg0) on the carbonaceous adsorbent was studied in a fixed bed reactor.The dynamic adsorption capacity of carbonaceous adsorbent increased with influent mercury concentration,from 23.6μg·g-1at 12.58μg·m-3to 87.9μg·g-1at 72.50μg·m-3,and decreased as the adsorption temperature increased,from 246 μg·g-1 at 25°C to 61.3μg·g-1 at 140°C,when dry nitrogen was used as the carrier gas.The carbonaceous adsorbent presented higher dynamic adsorption capacity than activated carbon,which was 81.2μg·g-1and 53.8μg·g-1respectively.The adsorption data were fitted to the Langmuir adsorption model.The physical and chemical adsorption were identified on the adsorbent.展开更多
An aminated hypercrosslinked macroporous polymeric adsorbent was synthesized and characterized. Adsorption isotherms for 1 amino 2 naphthol 4 sulfonic acid(1, 2, 4 acid) and 2 naphthol obtained from various bin...An aminated hypercrosslinked macroporous polymeric adsorbent was synthesized and characterized. Adsorption isotherms for 1 amino 2 naphthol 4 sulfonic acid(1, 2, 4 acid) and 2 naphthol obtained from various binary adsorption environments can be well fitted by Freundlich equation, which indicated a favorable adsorption process in the studied range. Adsorption for 1, 2, 4 acid was an endothermic process in comparison with that for 2 naphthol of an exothermic process. 2 naphthol molecules put a little influence on the adsorption capacity for 1, 2, 4 acid. However, the adsorption to 1, 2, 4 acid depressed that to 2 naphthol in a large extent for the stronger electrostatic interaction between 1, 2, 4 acid and adsorbent. The predominant mechanism can be contributed to the competition for adsorption sites. And the simultaneous environment was confirmed to be helpful to the selective adsorption towards 1,2,4 acid based on the larger selectivity index.展开更多
A series of copper-based activated carbon (AC) adsorbents were prepared in order to investigate the effect of Zn, Ce addition on Cu-based AC adsorbent for phosphine (PH3) adsorption removal from yellow phosphorous tai...A series of copper-based activated carbon (AC) adsorbents were prepared in order to investigate the effect of Zn, Ce addition on Cu-based AC adsorbent for phosphine (PH3) adsorption removal from yellow phosphorous tail gas. N2 adsorption isotherm and X-ray diffrac-tion (XRD) results suggested that the addition of Zn could increase the adsorbent ultramicropores, decrease the adsorbent supermicropores and the adsorbent average pore diameter. Therefore it enhanced the PH3 adsorption capacity. Appropriate amoun...展开更多
Activated carbon has been proven to be an effective adsorbent for the recovery of a wide variety of metal ions from aqueous solutions. In this research, the activated hard shell of Iranian apricot stones was used for ...Activated carbon has been proven to be an effective adsorbent for the recovery of a wide variety of metal ions from aqueous solutions. In this research, the activated hard shell of Iranian apricot stones was used for gold recovery from electro-plating wastewater. The effect of parameters such as dose and particle size of adsorbent,pH, agitation speed of mixing on the gold recovery was investigated. The results showed that under the optimum operating conditions more than 98% of gold ions were adsorbed onto activated carbon after just 3 h. In addition, the adsorbed gold could be eluted from this adsorbent by improved striping method. The process involves contact of gold-laden adsorbent with a strong base at ambient temperatures followed by elution with an aqueous solution containing an organic solvent. It was found that activated hard shell of apricot stones has the potential to replace im ported commercial activated carbons in gold adsorption processes.展开更多
The adsorption behavior of benzoic acid onto a water-compatible hypercrosslinked polymeric adsorbent NJ-8 wascompared with that onto macroporous Amberlite XAN-4. This paper focuses on the static equilibrium adsorption...The adsorption behavior of benzoic acid onto a water-compatible hypercrosslinked polymeric adsorbent NJ-8 wascompared with that onto macroporous Amberlite XAN-4. This paper focuses on the static equilibrium adsorption behaviors,the adsorption thermodynamics and the column dynamic adsorption profiles. Five isotherm models are used to fit the results.This shows that the Freundlich equation can give a perfect fit. The specific surface area of NJ-8 is about as high as that ofAmberlite XAD-4, but the adsorbing capacity for benzoic acid on NJ-8 is about 14.9%-64.8% higher than that on AmberliteXAD-4, which is attributed to its microporous mechanism and partial polarity. The negative values of the adsorptionenthalpy are indicative of an exothermic process. Both enthalpy and free energy changes of adsorption manifest a physicalsorption process. The negative values of the adsorption entropy indicate that adsorption is well consistent with the restrictedmobilities and the configurations of the adsorbed molecules on the surface of the studied adsorbents with superficialheterogeneity. Both adsorbents were used in mini-column experiments to demonstrate the higher breakthrough adsorbing capacity of the hypercrosslinked polymeric adsorbent NJ-8 to benzoic acid, as compared with that of Amberlite XAD-4.展开更多
Sewage sludge was used to develop an effective carbon adsorbent. This adsorbent was employed for the removal of azo dye such as Direct Dark Brown M and Acid Mordant Brown RH. The adsorption of dyes on this adsorbent w...Sewage sludge was used to develop an effective carbon adsorbent. This adsorbent was employed for the removal of azo dye such as Direct Dark Brown M and Acid Mordant Brown RH. The adsorption of dyes on this adsorbent was studied as a function of contact time, concentration, pH and temperature by batch method. The equilibrium adsorption capacity of a carbonaceous adsorbent prepared from city wastewater treatment plant was 502, and 329.7 mg/g of Direct Dark Brown M and Acid Mordant Brown RH, respectively. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with the Langmuir model. The rates of adsorption were found to conform to the Lagergren second-order kinetics with good correlation. The equilibrium adsorption capacity of the carbonaceous adsorbents was determined with the Langmuir equation as well as the Lagergren second-order rate equation. The most ideal pH for adsorption of two dyes onto adsorbents was found to be 3 and below. The results indicate that the carbonaceous adsorbents could be employed as a low cost adsorbent in the removal of dyes from wastewater.展开更多
基金supported by Shanxi Provincial Key Research and Development Project(202102090301026)Graduate Education Innovation Project of Taiyuan University of Science and Technology(SY2023024)。
文摘Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent materials were successfully synthesized by loading TEPA onto the pore MgO/ZrO_(2)carriers in the paper.The pore structure and surface characteristic of the samples were analyzed by using XRD,BET,FT-IR and SEM.The adsorbent materials exhibited microcrystalline state,and the crystallinity of all samples gradually decreased as the increase of TEPA content.The pore structure analysis indicated that the modification of MgO-ZrO_(2)adsorbents with TEPA led to the decrease of the specific surface areas,but the narrow micro-mesopore size distributions ranging from 1.8-12 nm in the adsorbents still were maintained.FT-IR spectrum results further verified the successful loading of TEPA.The adsorption capacity of the adsorbents for CO_(2)were tested by using an adsorption apparatus equipped with gas chromatography.The results indicated that when the TEPA loading reached 50%,the sample exhibited the maximum adsorption value for CO_(2),reaching 4.07 mmol/g under the operation condition of 75℃and atmospheric pressure.This result could be assigned to not only the base active sites but also the coexistence of both micropore and mesopore in the adsorbent.After three cycles tests for CO_(2)capture,the adsorption value of the sample for CO_(2)can also reached 95%of its original adsorption capacity,which verified the excellent cyclic operation stability.
文摘Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.
基金supported by National Natural Science Foundation of China(Grant Nos.52476223,22038011)the Programme of Introducing Talents of Discipline to Universities(Grant No.B23025)+1 种基金K.C.Wong Education Foundation,Fundamental Research Funds for the Central Universities(Grant No.xzy012023074)the Innovation Capability Support Program of Shaanxi(Grant Nos.2023KJKXX-004,2022KXJ-126).
文摘Conventional powder/pellet-based systems used for mitigating the environmental challenges posed by CO_(2)emissions present inefficiencies in mass/heat transfer,pressure drop,and clogging.Monolithic adsorption materials have emerged as a promising alternative to such systems.Additive manufacturing(AM)enables precise structural optimization and active component control in monolithic adsorbents,enhancing the adsorption kinetics while minimizing mechanical wear.This review examines the progress in AM-driven CO_(2)adsorbent development,covering the following aspects:(1)fabrication techniques for monolithic adsorbents and key metrics for evaluating their mechanical and adsorption properties,(2)applications of AM methods(extrusion,coating,gel spinning,and 3D printing)under fixed-source and direct-air capture scenarios,and(3)integrated systems combining CO_(2)adsorption and conversion.However,balancing adsorption performance with mechanical strength is a critical challenge.The trade-off can be addressed through advanced AM strategies such as hybrid material architectures and computational design.Future advancements will hinge on hybrid AM techniques to decouple structural and functional demands,AI/ML-driven multi-objective optimization for pore structure refinement and stress distribution,and lifecycle sustainability analytics to reduce energy use and material waste.By synergizing these approaches,next-generation monolithic adsorbents can achieve high capacity,mechanical robustness,and cost-effectiveness,positioning AM as a scalable and sustainable platform for carbon capture technologies.
基金supported by the Fundamental Research Funds for the National Natural Science Foundation of China 52225003,22208021,22109004the National Key R&D Program of China 2022YFB4101702.
文摘Although supported solid amine adsorbents have attracted great attention for CO_(2) capture,critical chemical deactivation problems including oxidative degradation and urea formation have severely restricted their practical applications for flue gas CO_(2) capture.In this work,we reveal that the nature of surface hydroxyl groups(metal hydroxyl Al–OH and nonmetal hydroxyl Si–OH)plays a key role in the deactivation mechanisms.The polyethyleneimine(PEI)supported on Al–OH-containing substrates suffers from severe oxidative degradation during the CO_(2) capture step due to the breakage of amine-support hydrogen bonding networks,but exhibits an excellent anti-urea formation feature by preventing dehydration of carbamate products under a pure CO_(2) regeneration atmosphere.In contrast,PEI supported on Si–OHcontaining substrates exhibits excellent anti-oxidative stability under simulated flue gas conditions by forming a robust hydrogen bonding protective network with Si–OH,but suffers from obvious urea formation during the pure CO_(2) regeneration step.We also reveal that the urea formation problem for PEI-SBA-15 can be avoided by the incorporation of an OH-containing PEG additive.Based on the intrinsic understanding of degradation mechanisms,we successfully synthesized an adsorbent 40PEI-20PEG-SBA-15 that demonstrates outstanding stability and retention of a high CO_(2) capacity of 2.45 mmol g^(−1) over 1000 adsorption–desorption cycles,together with negligible capacity loss during aging in simulated flue gas(10%CO_(2)+5%O_(2)+3%H_(2)O)for one month at 60–70℃.We believe this work makes great contribution to the advancement in the field of ultra-stable solid amine-based CO_(2) capture materials.
基金supported by the National Key Research and Development Program of China(2022YFA1504402)National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC)+2 种基金the National Natural Science Foundation of China(22472016 and U23B20169)Key R&D Program of Ningbo(No.2023Z144)the Fundamental Research Funds for the Central Universities(DUT22LAB601).
文摘Desulfurization technology is rather difficult and urgently needed for carbon dioxide(CO_(2))utilization in industry.A new Cu(I)-based adsorbent was synthesized and examined for the capacity of removing carbonyl sulfide(COS)from a CO_(2)stream in an effort to solve the competitive adsorption between CO_(2)and COS and to seek opportunity to advance adsorption capacity.A wide range of character-ization techniques were used to investigate the physicochemical properties of the synthesized Cu(I)adsorbent featuringπ-complexation and their correlations with the adsorption performance.Meanwhile,the first principal calculation software CP2K was used to develop an understanding of the adsorption mechanism,which can offer useful guidance for the adsorbent regeneration.The synthesized Cu(I)adsorbent,prepared by using copper citrate and citric acid on the ZSM-5(SiO_(2)/Al_(2)O_(3)=25)carrier,outperformed other adsorbents with varying formulations and carriers in adsorption capacities.Through optimization of the preparation and adsorption conditions for various adsorbents,the breakthrough adsorption capacity(Qb)for COS was further enhanced from 2.19 mg/g to 15.36 mg/g.The formed stableπ-complex bonds between COS and Cu(I),as confirmed by density func-tional theory calculations,were verified by the significant improvement in the adsorption capacity after regeneration at 600°C.The above advantages render the novel synthesized Cu(I)adsorbent a promising candidate featuring cost-effectiveness,high efficacy and good regenerability for desulfurization from a CO_(2)stream.
基金supported by the National Natural Science Foundation of China(Nos.52100062,and 52230001)China Postdoctoral Science Foundation(No.2023M732785).
文摘This study introduced a microwave-assisted pyrolysis method for the rapid and efficientpreparation of boron-doped porous biochar. The resulting biochar exhibited a large specificsurface area (933.39 m^(2)/g), a rich porous structure (1.044 cm3/g), and abundant active sites.Consequently, the prepared boron-doped porous biochar exhibited higher efficiency in adsorbingtetracycline with a maximum adsorption capacity of 413.223 mg/g, which significantlyexceeded that of unmodified biochar andmost commercial and reported adsorbents.The correlation analysis between the adsorption capacity and adsorbent characteristics revealedthat the formation of the –BCO_(2) group enhanced π–π electron donor–acceptor interactionsbetween boron-doped porous biochar and tetracycline. This mechanism mainlycontributed to the enhanced adsorption of tetracycline by boron-doped porous biochar. Additionally,the as-prepared boron-doped porous biochar exhibited broad applications in removingantibiotics (tetracycline), phenolics (bisphenol A), and dyes (methylene blue andrhodamine B). Moreover, the boron-doped porous biochar exhibited satisfactory stability,and its adsorption capacity can be nearly completely regenerated through simple heat treatment.This study provides new insights into the effectiveness of boron-doped carbonaceousmaterials in removing antibiotic contaminants.
基金supported by the Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(No.BK20220001)the Big Data Computing Center of Southeast University.
文摘Sodium-based adsorbents(Na_(2)CO_(3)/γ-Al_(2)O_(3))exhibit significant potential for commercial utilization in CO_(2)capture.Nevertheless,the requirement for high desorption temperatures poses challenges in terms of the high-quality heat needed for desorption.This study integrated ZrO_(2)doping into a sodium-based adsorbent to enhance its CO_(2)capture performance and lower its desorption temperature.The research investigated the CO_(2)adsorption capacity,reaction rate,and desorption characteristics of the ZrO_(2)-doped Na_(2)CO_(3)/γ-Al_(2)O_(3)adsorbents in detail.Additionally,the catalytic mechanism of ZrO_(2)was elucidated through Density Functional Theory calculations.The results showed that ZrO_(2)doping increased the adsorption rate and capacity of the adsorbent and reduced the desorption energy consumption.Desorption reaction activation energy reduced to 44.8 kJ/mol.The adsorbent doped with 3wt.%ZrO_(2)demonstrated the highest adsorption capacity and rate under optimal conditions,with a reaction temperature of 45℃,an adsorption capacity of 1.66 mmol/g,and a carbon conversion rate of 80.2%.ZrO_(2)acted as a catalyst,enhancing CO_(2)and H_(2)O adsorption,and facilitated CO_(2)desorption in the sodium-based adsorbent by forming[ZrO(OH)]^(+)and OH^(−)through H_(2)O adsorption activation.The lower energy barrier(0.17 eV)for the dissociative adsorption pathway of H_(2)O molecules on the ZrO_(2)surface further supported the role of ZrO_(2)in enhancing the overall adsorption performance of the adsorbent in the carbon capture process.Ultimately,the ZrO_(2)-doped Na_(2)CO_(3)/γ-Al_(2)O_(3)adsorbent was identified as having low desorption energy consumption,high adsorption capacity,and rate,offering potential cost reductions in CO_(2)capture and representing a promising adsorbent for this application.
基金Project(2008BAB35B04) supported by the National Key Technologies R&D Program of ChinaProject(2010QZZD003) supported by Central South University Advanced Research Program,China
文摘H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ extracted.The effects of lithium titanium ratio,calcining temperature and time were investigated on the synthesis of Li2TiO3.Li2TiO3,H2TiO3 and the adsorbed Li＋ adsorbent were characterized by XRD and SEM.The lithium adsorption properties were investigated by the adsorption kinetics and adsorption isotherm.The results indicate that H2TiO3 has an excellent adsorptive capacity for Li＋.Two simplified kinetic models including the pseudo-first-order and pseudo-second-order equations were selected to follow the adsorption processes.The rate constants of adsorption for these kinetic models were calculated.The results show that the adsorption process can be described by the pseudo-second-order equation,and the process is proved to be a chemical adsorption.The adsorption process that H2TiO3 adsorbs Li＋ in LiCl solution well fits the Langmuir equation with monolayer adsorption.
文摘Characteristics of 13x molecular sieve, silica gel and DH 5 and DH 7 prepared by authors, were investigated for the solid desiccant cooling system. The adsorption isotherms of DH 5 and DH 7 were experimentally determined. The performance parameters of adsorption capacity, air humidity, regeneration temperature and cooling volume were tested and discussed in detail. The results show that the properties of new adsorbents DH 5 and DH 7 on desiccant cooling are much better than those of common desiccants. The maximum adsorption volumes of water on DH 5 and DH 7 are 0.72?kg/kg and 0.73 ?kg/kg, respectively. The desiccant cooling volumes of DH 7and DH 5 are 2.2 and 1.3 times larger than those of silica gel and 13x(molecular sieve), respectively, after regeneration at 100?℃. The cooling volume per mass unit of DH 5 is 1.9 times larger that of 13x.
文摘A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.
文摘According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters including the total yield, adsorption of methylene blue, adsorption of iodine, BET surface area, micro-pore volume are 35%—49%, 16.5—38 mg/g, 285—362 mg/g, 185—359 m2/g, and 0.112—0.224 m3/g, respectively. According to the experimental data, the multi-linear regression method was adopted to fit the relations between the characteristic parameters and influential factors. At final, through optimization method, the optimal adsorbent is obtained when using 62 min as hold time and 1105K as pyrolysis temperature. Under the conditions, the adsorbent was produced and compared the characteristic parameters with model forecast value, the coherence is satisfied.
基金financial support from the NSFC project(21501052 and 91622119)the China Postdoctoral Science Foundation(2015M570304)+2 种基金Special Funding for Postdoctoral of Heilongjiang Province(LBH-TZ06019)the Science Foundation for Excellent Youth of Harbin City of China(2016RQQXJ099)UNPYSCT-2016173
文摘It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH ? 2–12, which can imply its universal utilization. The prepared BiFeO_3/Carbon nanocomposites have also displayed excellent capacities(over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO_3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO_3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.
基金financially supported by National Natural Science Foundation of China (No. 21377084)Shanghai Municipal Natural Science Foundation (No. 13ZR1421000)
文摘Adsorption is one of the most effective technologies in the treatment of colored matter containing wastewater. Graphene related composites display potential to be an effective adsorbent. However, the adsorption mechanism and their regeneration approach are still demanding more efforts. An effective magnetically separable absorbent, Fe3O4 and reduced graphene oxide(RGO) composite has been prepared by an in situ coprecipitation and reduction method. According to the characterizations of TEM, XRD, XPS, Raman spectra and BET analyses, Fe3O4 nanoparticles in sizes of 10-20 nm are well dispersed over the RGO nanosheets, resulting in a highest specific area of 296.2 m2/g. The rhodamine B adsorption mechanism on the composites was investigated by the adsorption kinetics and isotherms. The isotherms are fitting better by Langmuir model, and the adsorption kinetic rates depend much on the chemical components of RGO. Compared to active carbon, the composite shows 3.7 times higher adsorption capacity and thirty times faster adsorption rates. Furthermore,with Fe3O4 nanoparticles as the in situ catalysts, the adsorption performance of composites can be restored by carrying out a Fenton-like reaction, which could be a promising regeneration way for the adsorbents in the organic pollutant removal of wastewater.
基金financially supported by the National Natural Science Foundation of China (Nos. 21606113, 21676128, and 21722604)the International Postdoctoral Exchange Fellowship by China Postdoctoral Science Foundation (No. 20170055)
文摘Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specific surface area,h-BN-related nanostructures exhibit appealing adsorption propertiewhich can be widely applied for separation and purification towards energy and environment treatmenIn this review,recent progress in designing h-BN micro,nano-structure,controlled synthesis,performancoptimizing as well as energy and environment-related adsorption applications are summarized.Strategieto tailor the h-BN can be classified as morphology control,element doping,defect control and surfacmodification,focusing on how to optimize the adsorption performance.In order to insight the intrinsimechanism of tuning strategies for property optimization,the significant adsorption applications of h-Btowards hydrogen storage,CO2 capture,pollutants removal from water and adsorption desulfurization arpresented.
基金Supported by the Science and Technology Planning Project of Guangdong(2006A36701004)the Basic Research Program of the Ministry of Environmental Protection(zx_200910_02)
文摘The carbonaceous adsorbent was prepared from mixtures of dewatered sludge and sawdust with enhanced ZnCl2 chemical activation.Characteristics of the adsorbent were studied using scanning electron microscope(SEM) ,Fourier transform infrared spectroscopy(FT-IR) ,and adsorption of nitrogen.The surface analysis showed that the carbonaceous adsorbent had good specific surface and porosity(394 m 2 ·g-1of BET surface,0.12 and 0.10 ml·g-1of microporous and mesoporous volume,respectively) .The oxygen functional groups such as OH,C O and C O were found on the surface by FTIR and XPS(X-ray photoelectron spectroscopy) .The adsorption of elemental mercury(Hg0) on the carbonaceous adsorbent was studied in a fixed bed reactor.The dynamic adsorption capacity of carbonaceous adsorbent increased with influent mercury concentration,from 23.6μg·g-1at 12.58μg·m-3to 87.9μg·g-1at 72.50μg·m-3,and decreased as the adsorption temperature increased,from 246 μg·g-1 at 25°C to 61.3μg·g-1 at 140°C,when dry nitrogen was used as the carrier gas.The carbonaceous adsorbent presented higher dynamic adsorption capacity than activated carbon,which was 81.2μg·g-1and 53.8μg·g-1respectively.The adsorption data were fitted to the Langmuir adsorption model.The physical and chemical adsorption were identified on the adsorbent.
文摘An aminated hypercrosslinked macroporous polymeric adsorbent was synthesized and characterized. Adsorption isotherms for 1 amino 2 naphthol 4 sulfonic acid(1, 2, 4 acid) and 2 naphthol obtained from various binary adsorption environments can be well fitted by Freundlich equation, which indicated a favorable adsorption process in the studied range. Adsorption for 1, 2, 4 acid was an endothermic process in comparison with that for 2 naphthol of an exothermic process. 2 naphthol molecules put a little influence on the adsorption capacity for 1, 2, 4 acid. However, the adsorption to 1, 2, 4 acid depressed that to 2 naphthol in a large extent for the stronger electrostatic interaction between 1, 2, 4 acid and adsorbent. The predominant mechanism can be contributed to the competition for adsorption sites. And the simultaneous environment was confirmed to be helpful to the selective adsorption towards 1,2,4 acid based on the larger selectivity index.
基金Project supported by the Key Program of National High Technology Research and Development Program of China (863 Program) (2008AA062602)the Young and Middle-aged Academic and Technical Back-up Personnel Program of Yunnan Province (2007PY01-10)the Analysis and Measurement Foundation of Kunming University of Science & Technology
文摘A series of copper-based activated carbon (AC) adsorbents were prepared in order to investigate the effect of Zn, Ce addition on Cu-based AC adsorbent for phosphine (PH3) adsorption removal from yellow phosphorous tail gas. N2 adsorption isotherm and X-ray diffrac-tion (XRD) results suggested that the addition of Zn could increase the adsorbent ultramicropores, decrease the adsorbent supermicropores and the adsorbent average pore diameter. Therefore it enhanced the PH3 adsorption capacity. Appropriate amoun...
文摘Activated carbon has been proven to be an effective adsorbent for the recovery of a wide variety of metal ions from aqueous solutions. In this research, the activated hard shell of Iranian apricot stones was used for gold recovery from electro-plating wastewater. The effect of parameters such as dose and particle size of adsorbent,pH, agitation speed of mixing on the gold recovery was investigated. The results showed that under the optimum operating conditions more than 98% of gold ions were adsorbed onto activated carbon after just 3 h. In addition, the adsorbed gold could be eluted from this adsorbent by improved striping method. The process involves contact of gold-laden adsorbent with a strong base at ambient temperatures followed by elution with an aqueous solution containing an organic solvent. It was found that activated hard shell of apricot stones has the potential to replace im ported commercial activated carbons in gold adsorption processes.
基金This work was supported by the National Natural Science Foundation (No. 20274017) and the Science & Technology Council, of Jiangsu Province, China.
文摘The adsorption behavior of benzoic acid onto a water-compatible hypercrosslinked polymeric adsorbent NJ-8 wascompared with that onto macroporous Amberlite XAN-4. This paper focuses on the static equilibrium adsorption behaviors,the adsorption thermodynamics and the column dynamic adsorption profiles. Five isotherm models are used to fit the results.This shows that the Freundlich equation can give a perfect fit. The specific surface area of NJ-8 is about as high as that ofAmberlite XAD-4, but the adsorbing capacity for benzoic acid on NJ-8 is about 14.9%-64.8% higher than that on AmberliteXAD-4, which is attributed to its microporous mechanism and partial polarity. The negative values of the adsorptionenthalpy are indicative of an exothermic process. Both enthalpy and free energy changes of adsorption manifest a physicalsorption process. The negative values of the adsorption entropy indicate that adsorption is well consistent with the restrictedmobilities and the configurations of the adsorbed molecules on the surface of the studied adsorbents with superficialheterogeneity. Both adsorbents were used in mini-column experiments to demonstrate the higher breakthrough adsorbing capacity of the hypercrosslinked polymeric adsorbent NJ-8 to benzoic acid, as compared with that of Amberlite XAD-4.
文摘Sewage sludge was used to develop an effective carbon adsorbent. This adsorbent was employed for the removal of azo dye such as Direct Dark Brown M and Acid Mordant Brown RH. The adsorption of dyes on this adsorbent was studied as a function of contact time, concentration, pH and temperature by batch method. The equilibrium adsorption capacity of a carbonaceous adsorbent prepared from city wastewater treatment plant was 502, and 329.7 mg/g of Direct Dark Brown M and Acid Mordant Brown RH, respectively. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with the Langmuir model. The rates of adsorption were found to conform to the Lagergren second-order kinetics with good correlation. The equilibrium adsorption capacity of the carbonaceous adsorbents was determined with the Langmuir equation as well as the Lagergren second-order rate equation. The most ideal pH for adsorption of two dyes onto adsorbents was found to be 3 and below. The results indicate that the carbonaceous adsorbents could be employed as a low cost adsorbent in the removal of dyes from wastewater.
