In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utili...In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utilization of ethoxylated castor oil increases tensile strength of PU up to 2.75 times(from3.2 to 8.8MPa),compared to PU based on neat castor oil.The PU composites filed with birch flour,diatomite and their mixture were prepared using home-made dissolver with cutter-shaped attachment at the speed of 1500 min−1.The tensile strength of PU composites filled with birch flour increases up to two time at loading 5–30 wt.%.Application of combined birch flour/diatomite additives has similar effect.The tensile strength of PU composites based on one to one mixture of ethoxylated and neat castor oil and filled with birch flour or combined birch flour/diatomite additives increases sharply up to 16–17 fold(up to 18.1 MPa).The birch flour and diatomite wellsoaked polymer matrix.The main factor determining mechanical performance is the morphology of PU samples and composites.Formation of ordered lamella-like structure of amorphous phase of PU matrix leads to an increase in mechanical performance and glass transition temperatures.Formation of disordered unstructured soft phase of starting PU leads to a decline of these functional properties.展开更多
A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrai...A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrained specimen test（TSRST） of the asphalt mixtures. The results show that the low temperature performance of diatomite asphalt is better than that of neat asphalt. The glass transition temperature can reflect the low temperature performance of the diatomite asphalt better and has a good relationship with breaking temperatures. Besides, the TSRST, the bending test, the compressing test and the contraction coefficient test are used to study the low temperature performance of the diatomite asphalt mixture. The results prove that the low temperature performance of the diatomite asphalt mixture is better than that of the neat asphalt mixture. The critical bending strain energy density and the compressing strain energy density of the diatomite asphalt mixture are greater than those of the neat asphalt mixture. After adding diatomite to the asphalt mixture, the contraction coefficient is reduced. Based on the above results, the anti-cracking mechanism of the diatomite asphalt mixture is analyzed from the angle of contraction performance and breaking energy.展开更多
Persulfate(PS)-based oxidation technologies are attracting increasing attentions in water treatment due to their high efficiency and stability.In this study,a novel diatomite supported MnCeOx composite(MnCeOx/diatomit...Persulfate(PS)-based oxidation technologies are attracting increasing attentions in water treatment due to their high efficiency and stability.In this study,a novel diatomite supported MnCeOx composite(MnCeOx/diatomite) was prepared and characterized for activation of PS to degrade organic pollutants.Results indicated that diatomite not only dispersed MnCeOx and increased the specific surface area of catalyst,but also improved the low-valence metal site(Mn^2+and Ce^3+) and reactive oxygen species site(-OH) of MnCeOx,thus enhancing the activities of MnCeOx.MnCeOx/diatomite/PS showed high efficiency for multiple dyes and pharmaceutical pollutants.Constant rate(k) of MnCeOx/diatomite(kMnCeOx/diatomite) was three times higher than the sum of constant rate of MnCeOx(kMnCeOx)and constant rate of diatomite(kdiatomite).In addition,MnCeOx/diatomite showed wide pH application(5-9).Cl^- and NO3^2- had no effect while SO4^2- and humid acid had slightly negative effects on MnCeOx/diatomite/PS system.Moreover,MnCeOx/diatomite showed good reusability and stability.Mechanism analyses indicated that electron transfer of Mn and Ce attributed to the activation of PS and oxygen to produce free radicals.SO4·^-,·OH and O2·^-on the surface of catalyst were the main active free radicals to attack pollutants.展开更多
A new potassium nitrate （KNO3）]diatomite shape-stabilized composite phase change material （SS- CPCM） was prepared by the mixing and sintering method. KNO3 served as the phase change material （PCM） for thermal en...A new potassium nitrate （KNO3）]diatomite shape-stabilized composite phase change material （SS- CPCM） was prepared by the mixing and sintering method. KNO3 served as the phase change material （PCM） for thermal energy storage, while diatomite acted as the carrier matrix to provide the structural strength and prevent the leakage of PCM. It was found that KNO3 could be retained 65 wt% into pores and on surfaces of diatomite without the leakage of melted KNO3 from the SS-CPCM. The calculated filling rate of molten KNO3 that could enter into the disc-like shape pore of diatomite verified the scanning elec- tronic microscopy images of SS-CPCM. X-ray diffraction and Fourier transform infrared spectroscopy results showed that no reaction occurred between KNO3 and diatomite, performing good compatibility. Accord- ing to the differential scanning calorimetry results, after 50 thermal cycles, the phase change temperatures for melting and freezing of SS-CPCM with 65 wt% KNO3 were changed from 330.23 ℃ and 332.90 ℃ to 330.11 ℃ and 332.84 ℃ and corresponding latent heats varied from 60.52 J/g and 47.30 J/g to 54.64 J/g and 41.25 J/g, respectively. The KNO3/diatomite SS-CPCM may be considered as a potential storage media in solar power plants for thermal energy storage.展开更多
Nano TiOembedded in diatomite(NTED)synthesis materials were prepared by a sol-gel method in absolute ethyl alcohol suspension. NTED synthesis materials have a higher specific surface area and larger pore volume using ...Nano TiOembedded in diatomite(NTED)synthesis materials were prepared by a sol-gel method in absolute ethyl alcohol suspension. NTED synthesis materials have a higher specific surface area and larger pore volume using micromeritics ASAP 2020. The result of characterization was measured by X-ray diffraction(XRD),Fourier transform infrared(FT-IR) spectroscopy, scanning electron microscope(SEM), and energy dispersive spectroscopy(EDS). The cyanide wastewater was employed to evaluate the adsorption capacity and photocatalytic activity of prepared NTED synthesis materials. The better photocatalytic activity and adsorption capacity of NTED synthesis materials are attributed to their high surface area and higher UV absorption intensity for the cyanide wastewater.展开更多
Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differ...Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differential thermal analysis, and the phase and microstructure were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicated that the carriers were encapsulated by nano-TiO2 with a thickness of 300-450 nm. The main crystalline phase of TiO2 calcined at 650~C was anatase, and the average grain size was 8.3 nm. The FT-IR absorption bands at 955.38 cm1 suggested that new chemical bonds among Ti, O, and Si had formed in the composites. The photocatalytic （PC） activity of the composites was investigated un- der UV irradiation. Furthermore, the photodegradation kinetics of formaldehyde was investigated using the composites as the cores of an air cleaner. A kinetics study showed that the reaction rate constants of the gas-phase PC reaction of formaldehyde were k = 0.576 mg＇m3·min^-1 and K = 0.048 m3/mg.展开更多
Through the study of the corrosion behavior of Q235 steel in actual Yingtan soil and two simulated acidic soils with different water contents, the calculation of corrosion mass losses, and the analysis of the corrosio...Through the study of the corrosion behavior of Q235 steel in actual Yingtan soil and two simulated acidic soils with different water contents, the calculation of corrosion mass losses, and the analysis of the corrosion mor- phologies and products by means of scanning electron microscope （SEM） and X-ray diffraction （XRD）, the results demonstrated that the diatomite soil could simulate the corrosion in actual soil veritably. In both actual soil and simu- lated soil with 16.4% water content, the corrosion rates of Q235 steel were approximately 0.1 mm/a, the corrosion morphologies were mainly extension and connection of corrosion spots on sample surface, and the corrosion products were composed of a-FeOOH, γ-FeOOH, Fe3 O4 and Fe2O3. When other media conditions remained unchanged, the corrosion area of Q235 steel was larger in simulated soil with 34.5 % water content, and the corrosion rate reached 0.48 mm/a after 360 h of corrosion, which was nearly 5 times as the value in actual soil. Compared with the corro- sion products in actual soil, the proportion of γ-FeOOH in simulated soil with 34.5 % water content was higher, and the wα-FeOOH/wγ-FeOOH ratio was 1. 4, which was only 1/3 of the value in actual soil.展开更多
We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modifi...We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.展开更多
The feasibility of utilizing molybdenum tailing and diatomite as siliceous materials to prepare calcium silicate board was explored.The influences of molybdenum tailing/diatomite proportion on hydration characteristic...The feasibility of utilizing molybdenum tailing and diatomite as siliceous materials to prepare calcium silicate board was explored.The influences of molybdenum tailing/diatomite proportion on hydration characteristics,thermal conductivity,water absorption,flexural strength and moisture adsorption-desorption property of calcium silicate board were investigated in detail.The experimental results reveal that molybdenum tailing is environmentally friendly to prepare building materials.The main hydration products in calcium silicate board under autoclaved condition are C-S-H with low crystallinity and tobermorite.Molybdenum tailing is favorable to the formation of tobermorite.The flexural strength and bulk density of the calcium silicate board gradually increase when the content of molybdenum tailing increases.Netlike C-S-H is formed with the increase of diatomite content during autoclaved curing process,resulting in the enhancement of moisture adsorptiondesorption performance and the reduction of thermal conductivity.The optimal content of molybdenum tailing is 20%,furthermore,the flexual strength and thermal conductivity of calcium silicate board at this content meet the Chinese standard JC/T564.1-2008.展开更多
Diatomite was used as raw material to prepare sodium silicate with a modulus of 3.1 by alkali dissolution method and the resulted sodium silicate solution was employed as a precursor. Methyl methaerylate monomers were...Diatomite was used as raw material to prepare sodium silicate with a modulus of 3.1 by alkali dissolution method and the resulted sodium silicate solution was employed as a precursor. Methyl methaerylate monomers were introduced in wet gels through solution-immersion, and upon heating at 70 ℃, the mesoporous surfaces throughout the skeletal framework were coated with the polymer layer. PMMA modified silica aerogels were successfully synthesized via ambient pressure drying. The properties were investigated by FT- IR, NMR, TGA, nitrogen adsorption-desorption, FESEM and nano-indentation, etc. Results indicate that with the increasing of PMMA incorporated into silica aerogels, the bulk density and the BET surface area increase, the porosity decreases. Through the observation of FESEM, it is found that the interconnecting pores and the big pores add, the pore size distribution expands from 5-17 to 28-150 urn. By comparison, the PMMA modified silica aerogels achieve a 52-fold increase in hardness and a 10-fold increase in modulus.展开更多
The purpose of this work is to study the possibility of anionic dyes Reactive Red M-8B（RR） and Direct Green B（DG） adsorbed on chitosan-modified diatomite. The characteristics of adsorbent, adsorption isotherms and...The purpose of this work is to study the possibility of anionic dyes Reactive Red M-8B（RR） and Direct Green B（DG） adsorbed on chitosan-modified diatomite. The characteristics of adsorbent, adsorption isotherms and the influence of adsorption time, temperature and pH were researched in this work. The results show that the mo- dified diatomite had a much better adsorption capability than the natural diatomite. The adsorption capacities of chitosan-modified diatomite for RR and DG were 94.46 and 137.0 mg/g, respectively. Both adsorption time and adsorption temperature provided a positive effect on the dye adsorption. Within the experimental pH range, the adsorbance was enhanced at lower pH but reduced sharply at high pH. On the basis of the experimental results and discussion, electrostatic attraction is considered as the main mechanism of this chemisorption.展开更多
Diatomite is a kind of natural low-cost mineral material. It has a number of unique physical properties and has been widely used as an adsorbent in wastewater treatment. This study was conducted to investigate the aer...Diatomite is a kind of natural low-cost mineral material. It has a number of unique physical properties and has been widely used as an adsorbent in wastewater treatment. This study was conducted to investigate the aerobic biodegradation of coal gasification wastewater with and without diatomite addition. Experimental results indicated that diatomite added in the activated sludge system could promote the biomass and also enhance the performance of the sludge settling. The average mixed-liquor volatile suspended solids （MLVSS） is increased from 4055 mg.L^-1 to 4518 mg.L^-1 and the average settling volume （SV） are changed only from 45.9% to 47.1%. Diatomite additive could enhance the efficiency of chemical oxygen demand （COD） and total phenols removal from the wastewater. The COD removal increased from 73.3% to near 80% and the total phenols removal increased from 81.4% to 85.8%. The mechanisms of the increase of biomass and pollutants removal may correlates to the improvement of bioavailability and sludge settlement characteristics by diatomite added. Micrograph of the sludge in the diatomite-activated sludge system indicated that the diatomite added could be the carrier of the microbe and also affect the biomass and pollutant removal.展开更多
Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load pheno...Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load phenolic resin, carbonization and activation isolated air. The influences of impregnation, curing, carbonization, activation etc. on the material property were discussed. The iodine value, SEM, elemental analyzer, BET and spectrum analysis chart were used to characterize the microstructures and performance of material at different conditions. The results showed that the excellent comprehensive property of activated carbon functional ceramic was gained when it adsorbed phenolic resin in 4 h under vacuum condition at curing temperature of 150 ℃ for 0.5 h and carbonization temperature of 600 ℃ for 1.0 h, and then put into 25wt% KOH for 4.0 h at activation temperature of 700 ℃ for 1.5 h. The iodine value is 176.9 mg/g, the specific surface area can reach 86.3 m2/g and the yield of carbonization is 50.48%.展开更多
Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of o...Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of only 372 mAh·g?1,which cannot meet the everincreasing demand of LIBs for high energy density.Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites.Synthesis of nanoscale Si in a facile,cost-effective way,however,still poses a great challenge.In this work,nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source.It was found that the nanoscale Si prepared under optimized conditions(800°C,10 h)can deliver a high initial specific capacity(3053 mAh·g?1 on discharge,2519 mAh·g?1 on charge)with a high first coulombic efficiency(82.5%).When using sand-milled diatomite as a precursor,the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency(85.6%).The Si–C(Si:graphite=1:7 in weight)composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 mAh·g?1 at 100 mA·g?1),good rate capability(587 mAh·g?1 at 500 mA·g?1),and a long cycle life(480 mAh·g?1 after 200 cycles at 500 mA·g?1).This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.展开更多
The lithium–sulfur batteries show the great potential to be the most promising candidate for high energy applications. However, the shuttling of soluble polysulfides deteriorates the battery performance tremendously....The lithium–sulfur batteries show the great potential to be the most promising candidate for high energy applications. However, the shuttling of soluble polysulfides deteriorates the battery performance tremendously. To suppress the diffusion of soluble polysulfides, diatomite that has abundant natural three-dimensional ordered pores is incorporated into the cathode to trap polysulfides. The composite cathode material(S-DM-AB for short), including sulfur(S), diatomite(DM), and acetylene black(AB) is prepared by an impregnation method. For comparison, another composite cathode material(S-AB for short) including sulfur and acetylene black is also prepared by the same method. The battery with S-DMAB composite cathode material delivers a discharge capacity of 531.4 m Ah/g after 300 cycles at 2 C with a capacity retention of 51.6% at room temperature. By contrast, the battery with S-AB composite cathode material delivered a capacity of only 196.9 m Ah/g with a much lower capacity retention of 18.6% under the same condition. The addition of diatomite in the cathode is proved to be a cheap and effective way to improve the life time of the lithium sulfur batteries.展开更多
Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be re...Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of n ZVI.In general,the nano three-dimensional network formed by n ZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA,and further formed more active sites,which made NDA have better performance in activating PMS to degrade BPA than pure n ZVI.The pseudo-first-order reaction rate constant of 50-NDA(50%-n ZVI/diatomite)is almost 3 times higher than that of pure n ZVI.Besides,the electron paramagnetic resonance(EPR)and radical quenching experiments showed that the activation process was dominated by the sulfate radical(SO_(4)^(-))and hydroxyl radical(·OH)produced by Fe;oxidation.The generated electrons promote the self-decomposition of PMS to produce singlet oxygen(^(1)O_(2)),and then the valence state of iron changes to produce free radicals.In addition,the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer(LC-MS).This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.展开更多
Flower-, wire-, and sheet-like MnO2-deposited diatomites have been prepared using a hydrothermal method with Mn（Ac）2, KMnO4 and/or MnSO4 as Mn source and diatomite as support. Physical properties of the materials we...Flower-, wire-, and sheet-like MnO2-deposited diatomites have been prepared using a hydrothermal method with Mn（Ac）2, KMnO4 and/or MnSO4 as Mn source and diatomite as support. Physical properties of the materials were characterized by means of numerous analytical techniques, and their behaviors in the adsorption of chromium（VI） were evaluated. It is shown that the IvinO2-deposited diatomite samples with different morphologies possessed high surface areas and abundant surface hydroxyl groups （especially the wire-like MnO2/diatomite sample）. The wire-like MnO2/diatomite sample showed the best performance in the removal of Cr（VI）, giving the maximum Cr（VI） adsorption capacity of 101 mg/g.展开更多
Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-ef...Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-efficient removal of indoor formaldehyde(HCHO).First,the optimal preparation conditions of the two composites were determined,and then their microstructures and morphologies were characterized and analyzed.Batch HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption properties.Experimental results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process,and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g^(-1),respectively.The thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and exothermic.The abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO.展开更多
Highly efficient and sustainable conversion technologies to generate uniform sodalite(Na8(AlSiO4)6(OH)2)zeolite micro spheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystalliza...Highly efficient and sustainable conversion technologies to generate uniform sodalite(Na8(AlSiO4)6(OH)2)zeolite micro spheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystallization route were developed in the present study.The synthesis process can be considered as an in-situ zeolitization of diatomite precursor without involving any me so scale template and any post-synthetic modification.The mass ratios of diatomite and AlCl3·6 H2 O have remarkable effect on the morphology,crystal structure and porosity of sodalite zeolite product.The preferred sodalite microspheres with uniform mesoporous of size 3.5-5.5 nm and large surface area of 162.5 m2/g exhibit well removal performance for heavy metal ions(Pb(II),Cd(II),Zn(II),and Cu(II)),with the highest adsorption abilities for Pb(II)ions of 365 mg/g.In addition,the effect of contact time,initial ion concentration,competitive adsorption and solution pH were evaluated.The removal performance results from synergistic effects of dominating cation-exchange and additional surface chemisorption.The study may broadly help unveil chemical control reactions of the zeolitization processes of diatomite,and thus facilitates the development of promising zeolite materials for the use in natural and engineered aquatic environments by recvcling waste diatomite resources.展开更多
文摘In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utilization of ethoxylated castor oil increases tensile strength of PU up to 2.75 times(from3.2 to 8.8MPa),compared to PU based on neat castor oil.The PU composites filed with birch flour,diatomite and their mixture were prepared using home-made dissolver with cutter-shaped attachment at the speed of 1500 min−1.The tensile strength of PU composites filled with birch flour increases up to two time at loading 5–30 wt.%.Application of combined birch flour/diatomite additives has similar effect.The tensile strength of PU composites based on one to one mixture of ethoxylated and neat castor oil and filled with birch flour or combined birch flour/diatomite additives increases sharply up to 16–17 fold(up to 18.1 MPa).The birch flour and diatomite wellsoaked polymer matrix.The main factor determining mechanical performance is the morphology of PU samples and composites.Formation of ordered lamella-like structure of amorphous phase of PU matrix leads to an increase in mechanical performance and glass transition temperatures.Formation of disordered unstructured soft phase of starting PU leads to a decline of these functional properties.
基金The National Natural Science Foundation of China(No.50778057)
文摘A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrained specimen test（TSRST） of the asphalt mixtures. The results show that the low temperature performance of diatomite asphalt is better than that of neat asphalt. The glass transition temperature can reflect the low temperature performance of the diatomite asphalt better and has a good relationship with breaking temperatures. Besides, the TSRST, the bending test, the compressing test and the contraction coefficient test are used to study the low temperature performance of the diatomite asphalt mixture. The results prove that the low temperature performance of the diatomite asphalt mixture is better than that of the neat asphalt mixture. The critical bending strain energy density and the compressing strain energy density of the diatomite asphalt mixture are greater than those of the neat asphalt mixture. After adding diatomite to the asphalt mixture, the contraction coefficient is reduced. Based on the above results, the anti-cracking mechanism of the diatomite asphalt mixture is analyzed from the angle of contraction performance and breaking energy.
基金supported by the National Water Pollution Control and Treatment Science and Technology Major Project (No.2018ZX07110003).
文摘Persulfate(PS)-based oxidation technologies are attracting increasing attentions in water treatment due to their high efficiency and stability.In this study,a novel diatomite supported MnCeOx composite(MnCeOx/diatomite) was prepared and characterized for activation of PS to degrade organic pollutants.Results indicated that diatomite not only dispersed MnCeOx and increased the specific surface area of catalyst,but also improved the low-valence metal site(Mn^2+and Ce^3+) and reactive oxygen species site(-OH) of MnCeOx,thus enhancing the activities of MnCeOx.MnCeOx/diatomite/PS showed high efficiency for multiple dyes and pharmaceutical pollutants.Constant rate(k) of MnCeOx/diatomite(kMnCeOx/diatomite) was three times higher than the sum of constant rate of MnCeOx(kMnCeOx)and constant rate of diatomite(kdiatomite).In addition,MnCeOx/diatomite showed wide pH application(5-9).Cl^- and NO3^2- had no effect while SO4^2- and humid acid had slightly negative effects on MnCeOx/diatomite/PS system.Moreover,MnCeOx/diatomite showed good reusability and stability.Mechanism analyses indicated that electron transfer of Mn and Ce attributed to the activation of PS and oxygen to produce free radicals.SO4·^-,·OH and O2·^-on the surface of catalyst were the main active free radicals to attack pollutants.
基金supported by the Program for New Century Excellent Talents in University (Grant No. NCET-08-828)the Program for the China Geological Survey (No. 1212011120323)the Fundamental Research Funds for the Central Universities (No. 2011YXL003)
文摘A new potassium nitrate （KNO3）]diatomite shape-stabilized composite phase change material （SS- CPCM） was prepared by the mixing and sintering method. KNO3 served as the phase change material （PCM） for thermal energy storage, while diatomite acted as the carrier matrix to provide the structural strength and prevent the leakage of PCM. It was found that KNO3 could be retained 65 wt% into pores and on surfaces of diatomite without the leakage of melted KNO3 from the SS-CPCM. The calculated filling rate of molten KNO3 that could enter into the disc-like shape pore of diatomite verified the scanning elec- tronic microscopy images of SS-CPCM. X-ray diffraction and Fourier transform infrared spectroscopy results showed that no reaction occurred between KNO3 and diatomite, performing good compatibility. Accord- ing to the differential scanning calorimetry results, after 50 thermal cycles, the phase change temperatures for melting and freezing of SS-CPCM with 65 wt% KNO3 were changed from 330.23 ℃ and 332.90 ℃ to 330.11 ℃ and 332.84 ℃ and corresponding latent heats varied from 60.52 J/g and 47.30 J/g to 54.64 J/g and 41.25 J/g, respectively. The KNO3/diatomite SS-CPCM may be considered as a potential storage media in solar power plants for thermal energy storage.
基金financially supported by the National Natural Science Foundation of China (No.51304129)the Natural Science Foundation of Shandong Province (No. ZR2013EEM005)the High Education Science Technology Program of Shandong Province (No. J12LA04)
文摘Nano TiOembedded in diatomite(NTED)synthesis materials were prepared by a sol-gel method in absolute ethyl alcohol suspension. NTED synthesis materials have a higher specific surface area and larger pore volume using micromeritics ASAP 2020. The result of characterization was measured by X-ray diffraction(XRD),Fourier transform infrared(FT-IR) spectroscopy, scanning electron microscope(SEM), and energy dispersive spectroscopy(EDS). The cyanide wastewater was employed to evaluate the adsorption capacity and photocatalytic activity of prepared NTED synthesis materials. The better photocatalytic activity and adsorption capacity of NTED synthesis materials are attributed to their high surface area and higher UV absorption intensity for the cyanide wastewater.
基金financially supported by the National Natural Science Foundation of China (No. 50708037)the National Science Fund for Excellent Young Scholars of China (No. 51522402)+1 种基金the Science and Technology Research Projects in Zhengzhou (No. 141PPTGG388)the National Innovation and Entrepreneurship Training Program of the Undergraduate (No. 201610078034)
文摘Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differential thermal analysis, and the phase and microstructure were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicated that the carriers were encapsulated by nano-TiO2 with a thickness of 300-450 nm. The main crystalline phase of TiO2 calcined at 650~C was anatase, and the average grain size was 8.3 nm. The FT-IR absorption bands at 955.38 cm1 suggested that new chemical bonds among Ti, O, and Si had formed in the composites. The photocatalytic （PC） activity of the composites was investigated un- der UV irradiation. Furthermore, the photodegradation kinetics of formaldehyde was investigated using the composites as the cores of an air cleaner. A kinetics study showed that the reaction rate constants of the gas-phase PC reaction of formaldehyde were k = 0.576 mg＇m3·min^-1 and K = 0.048 m3/mg.
文摘Through the study of the corrosion behavior of Q235 steel in actual Yingtan soil and two simulated acidic soils with different water contents, the calculation of corrosion mass losses, and the analysis of the corrosion mor- phologies and products by means of scanning electron microscope （SEM） and X-ray diffraction （XRD）, the results demonstrated that the diatomite soil could simulate the corrosion in actual soil veritably. In both actual soil and simu- lated soil with 16.4% water content, the corrosion rates of Q235 steel were approximately 0.1 mm/a, the corrosion morphologies were mainly extension and connection of corrosion spots on sample surface, and the corrosion products were composed of a-FeOOH, γ-FeOOH, Fe3 O4 and Fe2O3. When other media conditions remained unchanged, the corrosion area of Q235 steel was larger in simulated soil with 34.5 % water content, and the corrosion rate reached 0.48 mm/a after 360 h of corrosion, which was nearly 5 times as the value in actual soil. Compared with the corro- sion products in actual soil, the proportion of γ-FeOOH in simulated soil with 34.5 % water content was higher, and the wα-FeOOH/wγ-FeOOH ratio was 1. 4, which was only 1/3 of the value in actual soil.
基金supported by Program for New Century Excellent Talents in University(NCET-10-0311)the National Natural Science Foundation of China(31000271)the Fundamental Research Funds for the Central Universities(DL11BB29)
文摘We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.
基金Funded by the National Key R&D Program of China(No.2017YFC0703206).
文摘The feasibility of utilizing molybdenum tailing and diatomite as siliceous materials to prepare calcium silicate board was explored.The influences of molybdenum tailing/diatomite proportion on hydration characteristics,thermal conductivity,water absorption,flexural strength and moisture adsorption-desorption property of calcium silicate board were investigated in detail.The experimental results reveal that molybdenum tailing is environmentally friendly to prepare building materials.The main hydration products in calcium silicate board under autoclaved condition are C-S-H with low crystallinity and tobermorite.Molybdenum tailing is favorable to the formation of tobermorite.The flexural strength and bulk density of the calcium silicate board gradually increase when the content of molybdenum tailing increases.Netlike C-S-H is formed with the increase of diatomite content during autoclaved curing process,resulting in the enhancement of moisture adsorptiondesorption performance and the reduction of thermal conductivity.The optimal content of molybdenum tailing is 20%,furthermore,the flexual strength and thermal conductivity of calcium silicate board at this content meet the Chinese standard JC/T564.1-2008.
基金Supported by the the National Natural Science Foundation of China(No.51278086)Petro China Innovation Fundation(No.2013D-5006-0606)+3 种基金the Program for New Century Excellent Talents in University by Ministry of Education of the People’s Republic of China(No.NCET-12-0084)Liaoning BaiQianWan Talents of Science and Technology Program(No.2012921073)Henan Open and Cooperation Project of Scienceand Technology(No.142106000023)Dalian Plan Projects of Science and Technology(No.2013A16GX113)
文摘Diatomite was used as raw material to prepare sodium silicate with a modulus of 3.1 by alkali dissolution method and the resulted sodium silicate solution was employed as a precursor. Methyl methaerylate monomers were introduced in wet gels through solution-immersion, and upon heating at 70 ℃, the mesoporous surfaces throughout the skeletal framework were coated with the polymer layer. PMMA modified silica aerogels were successfully synthesized via ambient pressure drying. The properties were investigated by FT- IR, NMR, TGA, nitrogen adsorption-desorption, FESEM and nano-indentation, etc. Results indicate that with the increasing of PMMA incorporated into silica aerogels, the bulk density and the BET surface area increase, the porosity decreases. Through the observation of FESEM, it is found that the interconnecting pores and the big pores add, the pore size distribution expands from 5-17 to 28-150 urn. By comparison, the PMMA modified silica aerogels achieve a 52-fold increase in hardness and a 10-fold increase in modulus.
基金Supported by the Research Fund of Environmental Protection Bureau in Jilin Province,China(No.2007-13)
文摘The purpose of this work is to study the possibility of anionic dyes Reactive Red M-8B（RR） and Direct Green B（DG） adsorbed on chitosan-modified diatomite. The characteristics of adsorbent, adsorption isotherms and the influence of adsorption time, temperature and pH were researched in this work. The results show that the mo- dified diatomite had a much better adsorption capability than the natural diatomite. The adsorption capacities of chitosan-modified diatomite for RR and DG were 94.46 and 137.0 mg/g, respectively. Both adsorption time and adsorption temperature provided a positive effect on the dye adsorption. Within the experimental pH range, the adsorbance was enhanced at lower pH but reduced sharply at high pH. On the basis of the experimental results and discussion, electrostatic attraction is considered as the main mechanism of this chemisorption.
基金Supported by the Shanghai Committee of Education (07ZZ158)
文摘Diatomite is a kind of natural low-cost mineral material. It has a number of unique physical properties and has been widely used as an adsorbent in wastewater treatment. This study was conducted to investigate the aerobic biodegradation of coal gasification wastewater with and without diatomite addition. Experimental results indicated that diatomite added in the activated sludge system could promote the biomass and also enhance the performance of the sludge settling. The average mixed-liquor volatile suspended solids （MLVSS） is increased from 4055 mg.L^-1 to 4518 mg.L^-1 and the average settling volume （SV） are changed only from 45.9% to 47.1%. Diatomite additive could enhance the efficiency of chemical oxygen demand （COD） and total phenols removal from the wastewater. The COD removal increased from 73.3% to near 80% and the total phenols removal increased from 81.4% to 85.8%. The mechanisms of the increase of biomass and pollutants removal may correlates to the improvement of bioavailability and sludge settlement characteristics by diatomite added. Micrograph of the sludge in the diatomite-activated sludge system indicated that the diatomite added could be the carrier of the microbe and also affect the biomass and pollutant removal.
基金Sponsored by the 2007 Fujian University and College New Century Excellent Talent Support Program (No. XSJRC2007-17)Natural Science Foundation of Fujian Province (No. 2010J01279)
文摘Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load phenolic resin, carbonization and activation isolated air. The influences of impregnation, curing, carbonization, activation etc. on the material property were discussed. The iodine value, SEM, elemental analyzer, BET and spectrum analysis chart were used to characterize the microstructures and performance of material at different conditions. The results showed that the excellent comprehensive property of activated carbon functional ceramic was gained when it adsorbed phenolic resin in 4 h under vacuum condition at curing temperature of 150 ℃ for 0.5 h and carbonization temperature of 600 ℃ for 1.0 h, and then put into 25wt% KOH for 4.0 h at activation temperature of 700 ℃ for 1.5 h. The iodine value is 176.9 mg/g, the specific surface area can reach 86.3 m2/g and the yield of carbonization is 50.48%.
基金the National Natural Science Foundation of China(No.51572238)Zhejiang Provincial Natural Science Foundation(No.LY19E020013)the Joint Research Project of Zhejiang University with Zotye Automobile Corporation Limited on Si-Based Anode Materials(No.P-ZH-2018-003).
文摘Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of only 372 mAh·g?1,which cannot meet the everincreasing demand of LIBs for high energy density.Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites.Synthesis of nanoscale Si in a facile,cost-effective way,however,still poses a great challenge.In this work,nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source.It was found that the nanoscale Si prepared under optimized conditions(800°C,10 h)can deliver a high initial specific capacity(3053 mAh·g?1 on discharge,2519 mAh·g?1 on charge)with a high first coulombic efficiency(82.5%).When using sand-milled diatomite as a precursor,the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency(85.6%).The Si–C(Si:graphite=1:7 in weight)composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 mAh·g?1 at 100 mA·g?1),good rate capability(587 mAh·g?1 at 500 mA·g?1),and a long cycle life(480 mAh·g?1 after 200 cycles at 500 mA·g?1).This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.
基金support from the National Natural Science Foundation of China(nos.21403202,21233006 and 21473164)the Key Program of the Natural Science Foundation of Hubei Province(no.2015CFA129)+1 种基金the Undergraduate Innovation Training Program of CUG(no.201610491138)the Excellent Youth of CUG Scholars
文摘The lithium–sulfur batteries show the great potential to be the most promising candidate for high energy applications. However, the shuttling of soluble polysulfides deteriorates the battery performance tremendously. To suppress the diffusion of soluble polysulfides, diatomite that has abundant natural three-dimensional ordered pores is incorporated into the cathode to trap polysulfides. The composite cathode material(S-DM-AB for short), including sulfur(S), diatomite(DM), and acetylene black(AB) is prepared by an impregnation method. For comparison, another composite cathode material(S-AB for short) including sulfur and acetylene black is also prepared by the same method. The battery with S-DMAB composite cathode material delivers a discharge capacity of 531.4 m Ah/g after 300 cycles at 2 C with a capacity retention of 51.6% at room temperature. By contrast, the battery with S-AB composite cathode material delivered a capacity of only 196.9 m Ah/g with a much lower capacity retention of 18.6% under the same condition. The addition of diatomite in the cathode is proved to be a cheap and effective way to improve the life time of the lithium sulfur batteries.
基金financially supported by the Beijing Natural Science Foundation(No.2202044)the National Postdoctoral Program for Innovative Talents(No.BX20190370)+1 种基金the China Postdoctoral Science Foundation(No.2020M680757)the Fundamental Research Funds for the Central Universities(No.2020YJSHH03)。
文摘Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of n ZVI.In general,the nano three-dimensional network formed by n ZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA,and further formed more active sites,which made NDA have better performance in activating PMS to degrade BPA than pure n ZVI.The pseudo-first-order reaction rate constant of 50-NDA(50%-n ZVI/diatomite)is almost 3 times higher than that of pure n ZVI.Besides,the electron paramagnetic resonance(EPR)and radical quenching experiments showed that the activation process was dominated by the sulfate radical(SO_(4)^(-))and hydroxyl radical(·OH)produced by Fe;oxidation.The generated electrons promote the self-decomposition of PMS to produce singlet oxygen(^(1)O_(2)),and then the valence state of iron changes to produce free radicals.In addition,the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer(LC-MS).This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.
基金financially supported by the Science and Technology Program of Jilin Province (Nos. 20130305015GX, 2014204037SF)the Beijing Natural Science Foundation (No. 2142008)the National Natural Science Foundation of China (No. 51225402)
文摘Flower-, wire-, and sheet-like MnO2-deposited diatomites have been prepared using a hydrothermal method with Mn（Ac）2, KMnO4 and/or MnSO4 as Mn source and diatomite as support. Physical properties of the materials were characterized by means of numerous analytical techniques, and their behaviors in the adsorption of chromium（VI） were evaluated. It is shown that the IvinO2-deposited diatomite samples with different morphologies possessed high surface areas and abundant surface hydroxyl groups （especially the wire-like MnO2/diatomite sample）. The wire-like MnO2/diatomite sample showed the best performance in the removal of Cr（VI）, giving the maximum Cr（VI） adsorption capacity of 101 mg/g.
基金financially supported by the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.C201903678)the Fundamental Research Funds for the Central Universities(2020YJSHH02)+1 种基金Fok Ying Tung Education Foundation,China(No.171042)the Yue Qi Young Scholar Project of the China University of Mining and Technology(Beijing)(No.2017 QN12)。
文摘Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-efficient removal of indoor formaldehyde(HCHO).First,the optimal preparation conditions of the two composites were determined,and then their microstructures and morphologies were characterized and analyzed.Batch HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption properties.Experimental results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process,and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g^(-1),respectively.The thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and exothermic.The abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO.
基金supported by the National Key R&D Program of China(No.2017YFB0310804)the Scientific and Technological Developing Scheme of Jilin Province(No.20190303119SF)+1 种基金the National Natural Science Foundation of China(No.51974011)the Key R&D Program of Ningxia Hui Autonomous Region(No.2019BFG02032)
文摘Highly efficient and sustainable conversion technologies to generate uniform sodalite(Na8(AlSiO4)6(OH)2)zeolite micro spheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystallization route were developed in the present study.The synthesis process can be considered as an in-situ zeolitization of diatomite precursor without involving any me so scale template and any post-synthetic modification.The mass ratios of diatomite and AlCl3·6 H2 O have remarkable effect on the morphology,crystal structure and porosity of sodalite zeolite product.The preferred sodalite microspheres with uniform mesoporous of size 3.5-5.5 nm and large surface area of 162.5 m2/g exhibit well removal performance for heavy metal ions(Pb(II),Cd(II),Zn(II),and Cu(II)),with the highest adsorption abilities for Pb(II)ions of 365 mg/g.In addition,the effect of contact time,initial ion concentration,competitive adsorption and solution pH were evaluated.The removal performance results from synergistic effects of dominating cation-exchange and additional surface chemisorption.The study may broadly help unveil chemical control reactions of the zeolitization processes of diatomite,and thus facilitates the development of promising zeolite materials for the use in natural and engineered aquatic environments by recvcling waste diatomite resources.
