Dye wastewater poses a significant threat to aquatic organisms due to its high toxicity.Reducing or eliminating the dye waste from the water is necessary for a healthy and sustainable aquaculture.This study investigat...Dye wastewater poses a significant threat to aquatic organisms due to its high toxicity.Reducing or eliminating the dye waste from the water is necessary for a healthy and sustainable aquaculture.This study investigated the adsorption properties of Congo red dye on Mytilus edulis shell powders prepared by calcination at 500℃,700℃,and 900℃.The modified shell powder products were analyzed by SEM(scanning eletron microscopy)and FTIR(fourier transform infrared spectroscopy)for the morphology and structural characterization.The effects of different calcination temperatures,reaction times,reaction temperatures,and initial concentration of Congo red on the adsorption properties were investigated.The adsorption kinetics and isothermal adsorption models were also established.The results revealed that the shell powder calcinated at 900℃showed the best adsorption capacity on Congo red from aqueous solution.The adsorption reaction reached equilibrium after 150 min and followed by the pseudo-second-order kinetic model.At 25℃,96.2%of the Congo red in the solution could be removed,and the adsorption capacity could reach at least 1015 mg g^(–1).The adsorption isotherm is fit with the Freundlich model,indicating a multiphase adsorption process.These results are helpful for cleaning and treating printing and dyeing effluents as well as high-value utilization of shell waste resources.展开更多
Porous materials are excellent adsorbents for the removal of organic dyes from sewage and play a significant role in environmental restoration.Herein,two ferrocene(Fc)-based covalent organic frameworks(Fc-COFs),namely...Porous materials are excellent adsorbents for the removal of organic dyes from sewage and play a significant role in environmental restoration.Herein,two ferrocene(Fc)-based covalent organic frameworks(Fc-COFs),namely FcTF-COF and FcBD-COF,are successfully synthesized for the first time through a solvothermal method,and the obtained Fc-COFs powders are used to adsorb Congo red(CR)from water.The results show that both FcTF-COF and FcBD-COF have superb adsorption performance towards CR with ultrahigh adsorption capability of 1672.2 mg g−1 and 1983.7 mg g−1 at pH=4.0,respectively,outperforming the majority of the reported solid porous adsorbents.The maximum adsorption of both Fc-COFs agrees with the Sips adsorption isothermal model,indicating that their adsorption was dominated by heterogeneous adsorption.The Coulombic interactions,hydrogen bonding,π-πinteractions and ion-dipolar interactions should all contribute to their ultrahigh CR adsorption capability and high-pH resistance performance regardless of the pH in the range of 4-9.In addition,after five cycles,both COFs still remain their exceptional high CR adsorption capabilities.This study offers a prospective organic porous adsorbent with promising applications for organic dye removal in sewage processing.展开更多
A BiOI/BiOBr S-scheme heterojunction photocatalyst was synthesized using a solvothermal method,and its ability to degrade Congo red was thoroughly investigated.The photocatalytic performance of the BiOI/BiOBr heteroju...A BiOI/BiOBr S-scheme heterojunction photocatalyst was synthesized using a solvothermal method,and its ability to degrade Congo red was thoroughly investigated.The photocatalytic performance of the BiOI/BiOBr heterojunction was compared with that of pure BiOBr and BiOI.The structural,morphological,optical,and electrical properties of the samples were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),UV-vis diffuse reflectance spectroscopy(UV-vis DRS),and zeta potential analysis.The degradation rate of Congo red was determined by spectrophotometry,revealing that the BiOI/BiOBr S-scheme heterojunction exhibited excellent photocatalytic performance,achieving a degradation rate of 96.8%for a 50 mg/L Congo red solution within 75 minutes.This rate was significantly higher than those achieved by pure BiOBr(77.2%)and BiOI(83.1%).Theoretical calculations indicate that the S-scheme heterojunction effectively facilitates the separation of photogenerated charge carriers while preserving the strong redox ability of the composite.These characteristics are identified as the key factors underlying the superior photocatalytic degradation efficiency of the BiOI/BiOBr S-scheme heterostructure.展开更多
Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their micro...Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuⅡ-MOF 1 and CuⅠ-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal(SCSC) transformation method, respectively,and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs.Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(Ⅵ) elimination at a short time of 15–25 min. Additionally, the congo red(CR) decolorization can be effectively enhanced in the presence of Cr(Ⅵ), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(Ⅵ) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles(95% for Cr(Ⅵ) after 14 runs, and 90% for CR after 10runs). Moreover, the Cr(Ⅵ)/CR degradation mechanism for Cu-MOF-alginate composite was investigated.展开更多
Pure TiO_(2)and copper-modified titania(Cu/TiO_(2))nanoparticles were synthesized through sol gel combined with the pyrolysis method for the removal of Congo red(CR)in wastewater treatment.Surface morphology and struc...Pure TiO_(2)and copper-modified titania(Cu/TiO_(2))nanoparticles were synthesized through sol gel combined with the pyrolysis method for the removal of Congo red(CR)in wastewater treatment.Surface morphology and structural evaluation utilized XRD,TEM,Raman,FTIR and BET techniques.Cu/TiO_(2)showed rich defects and a higher specific surface area than that of TiO_(2).The 1Cu/TiO_(2)(molar ratio Cu/TiO_(2)of 1/100)showed the best performance to adsorption of CR solution at different reaction conditions(contact duration,CR concentration,adsorbent dose,temperature,and initial pH).Adsorption kinetics and equilibrium isotherms were well-described with a pseudo-second-order kinetics and Freundlich model,respectively.The negative ΔG indicates stable adsorption of CR on the Cu/TiO_(2)surface.The adsorption efficiency only decreases by 6%after 5 cycles of adsorption regeneration.The successful synthesis of Cu/TiO_(2)offers a new possibility to address the problems related to CR dye from aqueous solutions.展开更多
Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high prepar...Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.展开更多
The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by us...The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by using XRD, FT-IR, SEM/EDX, TGA and BET. XRD and SEM studies proved that MWCNTs phases did not enter into the interlayers of LDHs, they dispersed over the LDHs surface homogeneously. BET results showed that MWCNTs/LDHs possessed hierarchically porous nanostructure with large surface area （124.974 m^2/g） and great pore volume （0.604 cm^3/g）. Batch experiments were conducted to study the adsorption efficiency of Congo red （CR）. It was worthy to note that MWCNTs/LDHs exhibited excellent adsorption performance with the maximum CR adsorption capacity of 595.8 mg/g in weak acidic environment. The adsorption kinetics and isotherm parameters can be well described by the pseudo-second-order and the Langmuir isotherm models, respectively. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic.展开更多
This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide.Central composite design was applied to conduct the experiments at differen...This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide.Central composite design was applied to conduct the experiments at different levels by altering three operating parameters.Activation temperature(766-934℃),CO2 flow rate(0.8-2.8 L·min^-1)and activation time(5-55 min)were the variables examined in this study.The effect of parameters on the specific surface area,total pore volume and burn-out rate of activated carbon was studied,and the influential parameters of methylene blue adsorption value were identified employing analysis of variance.The optimum conditions for maximum methylene blue adsorption value were:activation temperature=900℃,activation time=29.05 min and CO2 flow rate=1.8 L·min(-1).The activated carbon produced under optimum conditions was characterized by BET,FTIR and SEM.The adsorption behavior on congo red was studied.The effect of parameters on the adsorbent dosage,temperature,PH and initial congo red concentration was investigated.The adsorption properties of the activated carbon were investigated by kinetics.The equilibrium removal rate and maximum adsorption capacity reaches up to 94.72%,234 mg·g^-1,respectively when initial congo red concentration is 200 mg·L^-1 under adsorbent dosage(0.8 g·L^-1),temperature(30℃),PH7.展开更多
A dielectric barrier discharge （DBD） reactor with a rod-plate electrode configuration was used for the oxidative decomposition of Congo red dye in an aqueous solution. Plasma was generated in the gas space above the...A dielectric barrier discharge （DBD） reactor with a rod-plate electrode configuration was used for the oxidative decomposition of Congo red dye in an aqueous solution. Plasma was generated in the gas space above the water interface under atmospheric pressure. Discharge characteristics were analyzed by voltage-current waveforms. Effects of applied voltage, initial conductivity, and initial concentration were also analyzed. Congo red discoloration increased with increased applied voltage and decreased conductivity. The initial conductivity significantly influenced the Congo red discoloration. Under the same conditions, the highest discoloration rate was obtained at 25 mg/L. The presence of ferrous ions in the solutions had a substantial positive effect on Fenton dye degradation and flocculation. At an applied voltage of 20 kV, about 100% of dye was degraded after 4 min of Fe^2＋/DBD treatment. Results showed that adding a certain dosage of hydrogen peroxide to the wastewater could enhance the discoloration rate. Possible pathways of Congo red discoloration by DBD plasma were proposed based on GC/MS, FTIR, and UV-vis spectroscopy analyses.展开更多
Radio frequency （RF） underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was ...Radio frequency （RF） underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as .OH, .O, .H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conduc- tivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy （FT-IR） and Liquid Chromatography-Mass Spectrometry （LC- MS） data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.展开更多
A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or temp...A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.展开更多
We report on the synthesis of Sn-doped hematite nanoparticles(Sn-α-Fe_(2)O_(3) NPs)by the hydrothermal method.The prepared Sn-α-Fe_(2)O_(3) NPs had a highly pure and well crystalline rhombohedral phase with an avera...We report on the synthesis of Sn-doped hematite nanoparticles(Sn-α-Fe_(2)O_(3) NPs)by the hydrothermal method.The prepared Sn-α-Fe_(2)O_(3) NPs had a highly pure and well crystalline rhombohedral phase with an average particle size of 41.4 nm.The optical properties of as-synthesizedα-Fe_(2)O_(3) NPs show a higher bandgap energy(2.40-2.57 eV)than that of pure bulkα-Fe_(2)O_(3)(2.1 eV).By doping Sn intoα-Fe_(2)O_(3) NPs,the Sn-doped hematite was observed a redshift toward a long wavelength with in-creasing Sn concentration from 0%to 4.0%.The photocatalytic activity of Sn-dopedα-Fe_(2)O_(3) NPs was evaluated by Congo red(CR)dye degradation.The degradation efficiency of CR dye using Sn-α-Fe_(2)O_(3) NPs catalyst is higher than that of pureα-Fe_(2)O_(3) NPs.The highest degradation efficiency of CR dye was 97.8%using 2.5%Sn-dopedα-Fe_(2)O_(3) NPs catalyst under visible-light irradi-ation.These results suggest that the synthesized Sn-dopedα-Fe_(2)O_(3) nanoparticles might be a suitable approach to develop a photocatalytic degradation of toxic inorganic dye in wastewater.展开更多
A-site substituted La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites were prepared by sol-gel method and characterized using thermogravimetry/differential thermal analysis（TGA/DTA）, X-ray diffraction（XRD）, ultr...A-site substituted La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites were prepared by sol-gel method and characterized using thermogravimetry/differential thermal analysis（TGA/DTA）, X-ray diffraction（XRD）, ultraviolet-visible（UV-Vis） spectroscopy and transmission electron microscopy（TEM）. XRD analysis showed that the La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites derived after calcination at 800 oC were in single phase with orthorhombic structure. The particle size of all nano perovskites was found to be ~20 nm. The synthesized nano perovskites were tested for the photocatalytic decomposition of an azo dye, Congo red. The sequential behavior of La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nanoperovskites for photocatalytic decomposition of congo red in aqueous solution by visible light at room temperature was studied at various time intervals and the efficiency of degradation of the nanoperovskites was compared. Among all the A-site substituted La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites, Ba substituted compound showed the highest dye degradation.展开更多
A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under differ...A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared （FT-IR） spectrophotometer, X-ray diffraction （XRD） method, transmission electron microscope （TEM）, scanning electron microscope （SEM）, and thermal gravimetric （TG） analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red （CR） dye were investigated by controlling the amount ofhexadecyl trimethyl ammonium bromide （CTAB）, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 rag/g, with the amount of CTAB being 1.0 cation exchange capacity （CEC） of MMT, the weight ratio of CMC to OMMT being l：l, the reaction time being 6 h, and the reaction temperature being 60~C. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.展开更多
Cubic phase of Mg O nanoparticles were prepared by microwave-assisted combustion synthesis and investigated for the removal of toxic dyes like Congo Red(CR)and Trypan blue(TB).The crystallite size of the Mg O nanopart...Cubic phase of Mg O nanoparticles were prepared by microwave-assisted combustion synthesis and investigated for the removal of toxic dyes like Congo Red(CR)and Trypan blue(TB).The crystallite size of the Mg O nanoparticle was calculated to be 18 nm from XRD pattern.The sample was further characterized by FTIR,TGA and FESEM techniques.The dyes were subjected to prototypical batch adsorption process,including investigation of different parameters like Mg O dosage,dye concentration,solution pH,agitation speed and temperature.It was found that,0.2 g of Mg O NPs showed maximum removal efficiency for both the dyes(more than 98%),having 25 ppm of dye concentration at an acidic p H(3–4).The maximum loading capacity of Mg O NPs was obtained to be 136 mg/g and 132 mg/g for CR and TB,respectively.Different thermodynamic parameters like△G^(0),△H^(0)and△S^(0)were measured.The negative△H^(0)and the positive△S^(0)values for both the dyes correspond to an exothermic process and an increase in randomness of the adsorbent and dye.The isotherm analysis exhibited that the Freundlich model fits better to the experimental equilibrium data,suggesting heterogeneous surface of the nanoparticles.Whereas,the kinetic data revealed a pseudo 2 nd order rate for adsorption process.展开更多
The data obtained through this work revealed that the vermicompost is a natural adsorbent able to removal two textile dyes from an aqueous medium. The values of maximum adsorption capacity for congo red (23.25 mg/g) a...The data obtained through this work revealed that the vermicompost is a natural adsorbent able to removal two textile dyes from an aqueous medium. The values of maximum adsorption capacity for congo red (23.25 mg/g) and indigo blue (40.39 mg/g) obtained from the Mathematical Langmuir Model reveal it. The conditions of adsorbent mass, stirring time between adsorbent and dyes were optimized. Additionally, the values of Gibbs free energy demonstrate the predominance of physical interaction between both dyes and vermicompost. Through Langmuir constant values, it was possible to identify similar affinities between both dyes and vermicompost. The value of dimensionless constant indicates favorable adsorptions process. Finally, through physicochemical analysis from scanning electron microscopy and Fourier Transform Infra-Red Spectroscopy, the characteristics of vermicompost were verified revealing essential aspects to efficient adsorbent.展开更多
This work contributes to the improvement of the azo group which has outstanding electron donating capability and serves as excellent ligands in the field of coordination chemistry. The authors of this research deal wi...This work contributes to the improvement of the azo group which has outstanding electron donating capability and serves as excellent ligands in the field of coordination chemistry. The authors of this research deal with the microwave irradiation synthesis of some new Schiff bases derived from the biologically effective and photoactive Congo red [Ia-g]. The design and preparation of the structurally reversed analogous compounds to the above compounds [IIIa-d] were accomplished using the conventional chemical methods by keeping the benzidine moiety of Congo red as the nucleus of the synthesized compounds, doubling the number of the azo groups and inverting the way of their conjugation order with the azomethine groups. The structures of the newly prepared compounds were established on the basis of their FTIR and H1 NMR spectral data.展开更多
In the present study, it has been aimed to determine the non target effects of Congo red on soil enzyme activities namely amylase, protease, catalase, glucose oxidase and laccases, following the standard procedures. F...In the present study, it has been aimed to determine the non target effects of Congo red on soil enzyme activities namely amylase, protease, catalase, glucose oxidase and laccases, following the standard procedures. Further, it is also aimed to decolourize the dye effluents by using immobilized fimgal cultures namely Aspergillus spp. isolated from textile effluents and estimate the percentage of decolourization by dye decolourization assay method. The selected fungi were found efficient and dominant type in dye decolourization with the production of laccase and other enzymes. Except laccase, all the enzymes showed maximum activity at 14 days followed by declining trend at 21 days. Maximum enzyme activity was noticed with Aspergillus niger. 95% of decolourization was found within 4-24 h in sodium alginate immobilized fungal cultures compared to controls. The above results clearly indicate the efficiency of these fungi in selective bioremediation of dye contaminated sites.展开更多
Lignocellulose/montmorillonite （LNC/MMT） nanocomposites were prepared and characterized by FTIR and XRD. The adsorption of congo red （CR） on LNC/MMT nanocomposite was studied in detail. The effects of contact temp...Lignocellulose/montmorillonite （LNC/MMT） nanocomposites were prepared and characterized by FTIR and XRD. The adsorption of congo red （CR） on LNC/MMT nanocomposite was studied in detail. The effects of contact temperature, pH value of the dye solutions, contact time and concentration of dye solutions on the adsorption capacities of lignocellulose （LNC）, montmorillonite （MMT） and the nanocomposite were investigated. The adsorption kinetics and isotherms and adsorption thermodynamics of the nanocomposite for CR were also studied. The results show that the adsorption capacity of LNC/MMT nanocomosite is higher than that of LNC and MMT. All the adsorption processes fit very well with the pseudo-second-order and the Langmuir equation. From thermodynamic studies, it is seen that the adsorption is spontaneous and endothermic.展开更多
Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration ...Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration of 100 mg/L and initial pH = 5, and the adsorption time was 40 min, the CR removal efficiency was 98.41%. The adsorption trend of CR conformed to the second-order kinetics, and the adsorption isotherm follows the Freundlich isotherm model. Compared with RAS, MAS has a larger pore volume and specific surface area. The mechanism of action of MAS on CR was the interaction between membrane diffusion and internal diffusion, and the adsorption rate during the membrane diffusion was the fastest.展开更多
基金funded by the National Key Research and Development Program of China(No.2023YFD2401105)the Fujian Science and Technology Planning ProjectSTS Program(No.2021T3013)。
文摘Dye wastewater poses a significant threat to aquatic organisms due to its high toxicity.Reducing or eliminating the dye waste from the water is necessary for a healthy and sustainable aquaculture.This study investigated the adsorption properties of Congo red dye on Mytilus edulis shell powders prepared by calcination at 500℃,700℃,and 900℃.The modified shell powder products were analyzed by SEM(scanning eletron microscopy)and FTIR(fourier transform infrared spectroscopy)for the morphology and structural characterization.The effects of different calcination temperatures,reaction times,reaction temperatures,and initial concentration of Congo red on the adsorption properties were investigated.The adsorption kinetics and isothermal adsorption models were also established.The results revealed that the shell powder calcinated at 900℃showed the best adsorption capacity on Congo red from aqueous solution.The adsorption reaction reached equilibrium after 150 min and followed by the pseudo-second-order kinetic model.At 25℃,96.2%of the Congo red in the solution could be removed,and the adsorption capacity could reach at least 1015 mg g^(–1).The adsorption isotherm is fit with the Freundlich model,indicating a multiphase adsorption process.These results are helpful for cleaning and treating printing and dyeing effluents as well as high-value utilization of shell waste resources.
基金supported by the National Nat-ural Science Foundation of China(22465012)the Key Research and Development Project of Hainan Province,China(ZDYF2024GXJS005)the Major Science and Technology Plan of Hainan Province,China(ZDKJ202016).
文摘Porous materials are excellent adsorbents for the removal of organic dyes from sewage and play a significant role in environmental restoration.Herein,two ferrocene(Fc)-based covalent organic frameworks(Fc-COFs),namely FcTF-COF and FcBD-COF,are successfully synthesized for the first time through a solvothermal method,and the obtained Fc-COFs powders are used to adsorb Congo red(CR)from water.The results show that both FcTF-COF and FcBD-COF have superb adsorption performance towards CR with ultrahigh adsorption capability of 1672.2 mg g−1 and 1983.7 mg g−1 at pH=4.0,respectively,outperforming the majority of the reported solid porous adsorbents.The maximum adsorption of both Fc-COFs agrees with the Sips adsorption isothermal model,indicating that their adsorption was dominated by heterogeneous adsorption.The Coulombic interactions,hydrogen bonding,π-πinteractions and ion-dipolar interactions should all contribute to their ultrahigh CR adsorption capability and high-pH resistance performance regardless of the pH in the range of 4-9.In addition,after five cycles,both COFs still remain their exceptional high CR adsorption capabilities.This study offers a prospective organic porous adsorbent with promising applications for organic dye removal in sewage processing.
基金Funded by the National Natural Science Foundation of China(No.22262012)the Foundation of Hubei Key Laboratory of Biologic Resources Protection and Utilization(No.PT012214)+1 种基金Science and Technology Research Project of Education Department of Hubei Province(No.D20221903)Enshi Science and Technology Plan Project(No.D20230090)。
文摘A BiOI/BiOBr S-scheme heterojunction photocatalyst was synthesized using a solvothermal method,and its ability to degrade Congo red was thoroughly investigated.The photocatalytic performance of the BiOI/BiOBr heterojunction was compared with that of pure BiOBr and BiOI.The structural,morphological,optical,and electrical properties of the samples were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),UV-vis diffuse reflectance spectroscopy(UV-vis DRS),and zeta potential analysis.The degradation rate of Congo red was determined by spectrophotometry,revealing that the BiOI/BiOBr S-scheme heterojunction exhibited excellent photocatalytic performance,achieving a degradation rate of 96.8%for a 50 mg/L Congo red solution within 75 minutes.This rate was significantly higher than those achieved by pure BiOBr(77.2%)and BiOI(83.1%).Theoretical calculations indicate that the S-scheme heterojunction effectively facilitates the separation of photogenerated charge carriers while preserving the strong redox ability of the composite.These characteristics are identified as the key factors underlying the superior photocatalytic degradation efficiency of the BiOI/BiOBr S-scheme heterostructure.
基金supported by the National Natural Science Foundation of China(Nos.22077099,22171223 and 22307102)the Innovation Capability Support Program of Shaanxi(Nos.2023-CX-TD-75 and 2022KJXX-32)+5 种基金the Technology Innovation Leading Program of Shaanxi(Nos.2023KXJ-209 and 2024QCYKXJ-142)the Natural Science Basic Research Program of Shaanxi(Nos.2023-JC-YB-141 and 2022JQ-151)the Key Research and Development Program of Shaanxi(No.2024GH-ZDXM-22)Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.SWYY202206)the Shaanxi Fundamental Science Research Project for Chemistry&Biology(Nos.22JHZ010 and 22JHQ080)the Yan’an City Science and Technology Project(No.2022SLZDCY-002).
文摘Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuⅡ-MOF 1 and CuⅠ-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal(SCSC) transformation method, respectively,and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs.Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(Ⅵ) elimination at a short time of 15–25 min. Additionally, the congo red(CR) decolorization can be effectively enhanced in the presence of Cr(Ⅵ), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(Ⅵ) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles(95% for Cr(Ⅵ) after 14 runs, and 90% for CR after 10runs). Moreover, the Cr(Ⅵ)/CR degradation mechanism for Cu-MOF-alginate composite was investigated.
基金supported by the Inner Mongolia Natural Science Foundation(2024QN02011)basic scientific research business expense project of colleges and universities directly under Inner Mongolia(2023QNJS131 and 2024QNJS127)Science and Technology Plan Program of Inner Mongolia Autonomous Region(2023YFDZ0031).
文摘Pure TiO_(2)and copper-modified titania(Cu/TiO_(2))nanoparticles were synthesized through sol gel combined with the pyrolysis method for the removal of Congo red(CR)in wastewater treatment.Surface morphology and structural evaluation utilized XRD,TEM,Raman,FTIR and BET techniques.Cu/TiO_(2)showed rich defects and a higher specific surface area than that of TiO_(2).The 1Cu/TiO_(2)(molar ratio Cu/TiO_(2)of 1/100)showed the best performance to adsorption of CR solution at different reaction conditions(contact duration,CR concentration,adsorbent dose,temperature,and initial pH).Adsorption kinetics and equilibrium isotherms were well-described with a pseudo-second-order kinetics and Freundlich model,respectively.The negative ΔG indicates stable adsorption of CR on the Cu/TiO_(2)surface.The adsorption efficiency only decreases by 6%after 5 cycles of adsorption regeneration.The successful synthesis of Cu/TiO_(2)offers a new possibility to address the problems related to CR dye from aqueous solutions.
基金supported by the National Natural Science Foundation of China(51671052,51750110513,52250610222)the Fundamental Research Funds for the Central Universities(N182502042)the Liao Ning Revitilization Talents Program(XLYC1902105)。
文摘Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.
基金Project(21476269)supported by the National Natural Science Foundation of ChinaProject(14JJ2014)supported by Natural Science Foundation of Hunan Province,China
文摘The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by using XRD, FT-IR, SEM/EDX, TGA and BET. XRD and SEM studies proved that MWCNTs phases did not enter into the interlayers of LDHs, they dispersed over the LDHs surface homogeneously. BET results showed that MWCNTs/LDHs possessed hierarchically porous nanostructure with large surface area （124.974 m^2/g） and great pore volume （0.604 cm^3/g）. Batch experiments were conducted to study the adsorption efficiency of Congo red （CR）. It was worthy to note that MWCNTs/LDHs exhibited excellent adsorption performance with the maximum CR adsorption capacity of 595.8 mg/g in weak acidic environment. The adsorption kinetics and isotherm parameters can be well described by the pseudo-second-order and the Langmuir isotherm models, respectively. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China(LY16B060014)the Program for the Joint Research Fund for Overseas Chinese,Hong Kong and Macao Scholars of National Natural Science Foundation of China(Grant No.21628601)the Innovation and Development of Marine Economy Demonstration。
文摘This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide.Central composite design was applied to conduct the experiments at different levels by altering three operating parameters.Activation temperature(766-934℃),CO2 flow rate(0.8-2.8 L·min^-1)and activation time(5-55 min)were the variables examined in this study.The effect of parameters on the specific surface area,total pore volume and burn-out rate of activated carbon was studied,and the influential parameters of methylene blue adsorption value were identified employing analysis of variance.The optimum conditions for maximum methylene blue adsorption value were:activation temperature=900℃,activation time=29.05 min and CO2 flow rate=1.8 L·min(-1).The activated carbon produced under optimum conditions was characterized by BET,FTIR and SEM.The adsorption behavior on congo red was studied.The effect of parameters on the adsorbent dosage,temperature,PH and initial congo red concentration was investigated.The adsorption properties of the activated carbon were investigated by kinetics.The equilibrium removal rate and maximum adsorption capacity reaches up to 94.72%,234 mg·g^-1,respectively when initial congo red concentration is 200 mg·L^-1 under adsorbent dosage(0.8 g·L^-1),temperature(30℃),PH7.
基金supported by National Natural Science Foundation of China(No.51377075)the Natural Science Foundation of Jiangsu Province of China(Nos.BK20131412,BK20150951)
文摘A dielectric barrier discharge （DBD） reactor with a rod-plate electrode configuration was used for the oxidative decomposition of Congo red dye in an aqueous solution. Plasma was generated in the gas space above the water interface under atmospheric pressure. Discharge characteristics were analyzed by voltage-current waveforms. Effects of applied voltage, initial conductivity, and initial concentration were also analyzed. Congo red discoloration increased with increased applied voltage and decreased conductivity. The initial conductivity significantly influenced the Congo red discoloration. Under the same conditions, the highest discoloration rate was obtained at 25 mg/L. The presence of ferrous ions in the solutions had a substantial positive effect on Fenton dye degradation and flocculation. At an applied voltage of 20 kV, about 100% of dye was degraded after 4 min of Fe^2＋/DBD treatment. Results showed that adding a certain dosage of hydrogen peroxide to the wastewater could enhance the discoloration rate. Possible pathways of Congo red discoloration by DBD plasma were proposed based on GC/MS, FTIR, and UV-vis spectroscopy analyses.
基金supported by Natural Science Foundation of Jiangsu Education Committee of China (No.09KJA140005)
文摘Radio frequency （RF） underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as .OH, .O, .H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conduc- tivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy （FT-IR） and Liquid Chromatography-Mass Spectrometry （LC- MS） data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.
基金Supported by the National Natural Science Foundation of China(21276141)the State Key Laboratory of Chemical Engineering,China(SKL-Ch E-17A03)
文摘A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.
基金the financial support of Vietnam Academy of Science and Technology under project VAST01.04/18-19.
文摘We report on the synthesis of Sn-doped hematite nanoparticles(Sn-α-Fe_(2)O_(3) NPs)by the hydrothermal method.The prepared Sn-α-Fe_(2)O_(3) NPs had a highly pure and well crystalline rhombohedral phase with an average particle size of 41.4 nm.The optical properties of as-synthesizedα-Fe_(2)O_(3) NPs show a higher bandgap energy(2.40-2.57 eV)than that of pure bulkα-Fe_(2)O_(3)(2.1 eV).By doping Sn intoα-Fe_(2)O_(3) NPs,the Sn-doped hematite was observed a redshift toward a long wavelength with in-creasing Sn concentration from 0%to 4.0%.The photocatalytic activity of Sn-dopedα-Fe_(2)O_(3) NPs was evaluated by Congo red(CR)dye degradation.The degradation efficiency of CR dye using Sn-α-Fe_(2)O_(3) NPs catalyst is higher than that of pureα-Fe_(2)O_(3) NPs.The highest degradation efficiency of CR dye was 97.8%using 2.5%Sn-dopedα-Fe_(2)O_(3) NPs catalyst under visible-light irradi-ation.These results suggest that the synthesized Sn-dopedα-Fe_(2)O_(3) nanoparticles might be a suitable approach to develop a photocatalytic degradation of toxic inorganic dye in wastewater.
文摘A-site substituted La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites were prepared by sol-gel method and characterized using thermogravimetry/differential thermal analysis（TGA/DTA）, X-ray diffraction（XRD）, ultraviolet-visible（UV-Vis） spectroscopy and transmission electron microscopy（TEM）. XRD analysis showed that the La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites derived after calcination at 800 oC were in single phase with orthorhombic structure. The particle size of all nano perovskites was found to be ~20 nm. The synthesized nano perovskites were tested for the photocatalytic decomposition of an azo dye, Congo red. The sequential behavior of La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nanoperovskites for photocatalytic decomposition of congo red in aqueous solution by visible light at room temperature was studied at various time intervals and the efficiency of degradation of the nanoperovskites was compared. Among all the A-site substituted La0.8A0.2TiO3.5–δ（A=Ba, Sr, Ca） nano perovskites, Ba substituted compound showed the highest dye degradation.
基金supported by the Special Fund for National Forestry Industry Scientific Research in the Public Interest of China (Grant No. 201104004)the Natural Science Foundation of China (Grant No. 20867004)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region
文摘A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared （FT-IR） spectrophotometer, X-ray diffraction （XRD） method, transmission electron microscope （TEM）, scanning electron microscope （SEM）, and thermal gravimetric （TG） analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red （CR） dye were investigated by controlling the amount ofhexadecyl trimethyl ammonium bromide （CTAB）, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 rag/g, with the amount of CTAB being 1.0 cation exchange capacity （CEC） of MMT, the weight ratio of CMC to OMMT being l：l, the reaction time being 6 h, and the reaction temperature being 60~C. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.
文摘Cubic phase of Mg O nanoparticles were prepared by microwave-assisted combustion synthesis and investigated for the removal of toxic dyes like Congo Red(CR)and Trypan blue(TB).The crystallite size of the Mg O nanoparticle was calculated to be 18 nm from XRD pattern.The sample was further characterized by FTIR,TGA and FESEM techniques.The dyes were subjected to prototypical batch adsorption process,including investigation of different parameters like Mg O dosage,dye concentration,solution pH,agitation speed and temperature.It was found that,0.2 g of Mg O NPs showed maximum removal efficiency for both the dyes(more than 98%),having 25 ppm of dye concentration at an acidic p H(3–4).The maximum loading capacity of Mg O NPs was obtained to be 136 mg/g and 132 mg/g for CR and TB,respectively.Different thermodynamic parameters like△G^(0),△H^(0)and△S^(0)were measured.The negative△H^(0)and the positive△S^(0)values for both the dyes correspond to an exothermic process and an increase in randomness of the adsorbent and dye.The isotherm analysis exhibited that the Freundlich model fits better to the experimental equilibrium data,suggesting heterogeneous surface of the nanoparticles.Whereas,the kinetic data revealed a pseudo 2 nd order rate for adsorption process.
文摘The data obtained through this work revealed that the vermicompost is a natural adsorbent able to removal two textile dyes from an aqueous medium. The values of maximum adsorption capacity for congo red (23.25 mg/g) and indigo blue (40.39 mg/g) obtained from the Mathematical Langmuir Model reveal it. The conditions of adsorbent mass, stirring time between adsorbent and dyes were optimized. Additionally, the values of Gibbs free energy demonstrate the predominance of physical interaction between both dyes and vermicompost. Through Langmuir constant values, it was possible to identify similar affinities between both dyes and vermicompost. The value of dimensionless constant indicates favorable adsorptions process. Finally, through physicochemical analysis from scanning electron microscopy and Fourier Transform Infra-Red Spectroscopy, the characteristics of vermicompost were verified revealing essential aspects to efficient adsorbent.
文摘This work contributes to the improvement of the azo group which has outstanding electron donating capability and serves as excellent ligands in the field of coordination chemistry. The authors of this research deal with the microwave irradiation synthesis of some new Schiff bases derived from the biologically effective and photoactive Congo red [Ia-g]. The design and preparation of the structurally reversed analogous compounds to the above compounds [IIIa-d] were accomplished using the conventional chemical methods by keeping the benzidine moiety of Congo red as the nucleus of the synthesized compounds, doubling the number of the azo groups and inverting the way of their conjugation order with the azomethine groups. The structures of the newly prepared compounds were established on the basis of their FTIR and H1 NMR spectral data.
文摘In the present study, it has been aimed to determine the non target effects of Congo red on soil enzyme activities namely amylase, protease, catalase, glucose oxidase and laccases, following the standard procedures. Further, it is also aimed to decolourize the dye effluents by using immobilized fimgal cultures namely Aspergillus spp. isolated from textile effluents and estimate the percentage of decolourization by dye decolourization assay method. The selected fungi were found efficient and dominant type in dye decolourization with the production of laccase and other enzymes. Except laccase, all the enzymes showed maximum activity at 14 days followed by declining trend at 21 days. Maximum enzyme activity was noticed with Aspergillus niger. 95% of decolourization was found within 4-24 h in sodium alginate immobilized fungal cultures compared to controls. The above results clearly indicate the efficiency of these fungi in selective bioremediation of dye contaminated sites.
基金Special Fund for National Forestry Industry Scientific Research in the Public Interest of China(No.201104004)the National Natural Science Foundation of China(No.20867004)
文摘Lignocellulose/montmorillonite （LNC/MMT） nanocomposites were prepared and characterized by FTIR and XRD. The adsorption of congo red （CR） on LNC/MMT nanocomposite was studied in detail. The effects of contact temperature, pH value of the dye solutions, contact time and concentration of dye solutions on the adsorption capacities of lignocellulose （LNC）, montmorillonite （MMT） and the nanocomposite were investigated. The adsorption kinetics and isotherms and adsorption thermodynamics of the nanocomposite for CR were also studied. The results show that the adsorption capacity of LNC/MMT nanocomosite is higher than that of LNC and MMT. All the adsorption processes fit very well with the pseudo-second-order and the Langmuir equation. From thermodynamic studies, it is seen that the adsorption is spontaneous and endothermic.
文摘Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration of 100 mg/L and initial pH = 5, and the adsorption time was 40 min, the CR removal efficiency was 98.41%. The adsorption trend of CR conformed to the second-order kinetics, and the adsorption isotherm follows the Freundlich isotherm model. Compared with RAS, MAS has a larger pore volume and specific surface area. The mechanism of action of MAS on CR was the interaction between membrane diffusion and internal diffusion, and the adsorption rate during the membrane diffusion was the fastest.
