With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
It is acknowledged that injecting CO_(2) into oil reservoirs and saline aquifers for storage is a practical and affordable method for CO_(2) sequestration.Most CO_(2) produced from industrial exhaust contains impurity...It is acknowledged that injecting CO_(2) into oil reservoirs and saline aquifers for storage is a practical and affordable method for CO_(2) sequestration.Most CO_(2) produced from industrial exhaust contains impurity gases such as H_(2)S that might impact CO_(2) sequestration due to competitive adsorption.This study makes a commendable effort to explore the adsorption behavior of CO_(2)/H_(2)S mixtures in calcite slit nanopores.Grand Canonical Monte Carlo(GCMC)simulation is employed to reveal the adsorption of CO_(2),H_(2)S as well as their binary mixtures in calcite nanopores.Results show that the increase in pressure and temperature can promote and inhibit the adsorption capacity of CO_(2) and H_(2)S in calcite nanopores,respectively.CO_(2)exhibits stronger adsorption on calcite surface than H_(2)S.Electrostatic energy plays the dominating role in the adsorption behavior.Electrostatic energy accounts for 97.11%of the CO_(2)-calcite interaction energy and 56.33%of the H_(2)S-calcite interaction energy at 10 MPa and 323.15 K.The presence of H_(2)S inhibits the CO_(2) adsorption in calcite nanopores due to competitive adsorption,and a higher mole fraction of H_(2)S leads to less CO_(2) adsorption.The quantity of CO_(2) adsorbed is lessened by approximately 33%when the mole fraction of H_(2)S reaches 0.25.CO_(2) molecules preferentially occupy the regions near the po re wall and H_(2)S molecules tend to reside at the center of nanopore even when the molar ratio of CO_(2) is low,indicating that CO_(2) has an adsorption priority on the calcite surface over H_(2)S.In addition,moisture can weaken the adsorption of both CO_(2) and H_(2)S,while CO_(2) is more affected.More interestingly,we find that pure CO_(2) is more suitable to be sequestrated in the shallower formations,i.e.,500-1500 m,whereas CO_(2)with H_(2)S impurity should be settled in the deeper reservoirs.展开更多
In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-p...In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.展开更多
In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction m...In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.展开更多
Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(Ⅱ)-imprinted polymer for selective separation and enrichment of trace Pb(Ⅱ) from aqueous solution. The prepared materia...Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(Ⅱ)-imprinted polymer for selective separation and enrichment of trace Pb(Ⅱ) from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray diffractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb(Ⅱ) from aqueous solutions on Pb(Ⅱ)-imprinted polymer. The equilibrium was achieved in approximately 4,0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb(Ⅱ) on Pb(Ⅱ)-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb(Ⅱ) from the Pb(Ⅱ)-imprinted polymer were also studied in batch experiments. The prepared Pb(Ⅱ)-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb(Ⅱ) from water samples. The adsorption and desorption mechanisms were proposed.展开更多
The combined pollution of heavy metal Pb^2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on thre...The combined pollution of heavy metal Pb^2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb^2+ was examined using high-performance liquid chromatograph (HPLC). Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) 〉 0.98, irrespective of the presence of spiked Pb^2+. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb^2+ concentration in soil which indicated that the spiked of Pb^2+ in paddy soils would promote the sorption of BSM. AGo of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter (DOM) enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb^2+ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.展开更多
The study results of the effects of temperature and ionic strength on the adsorption kineties of Pb ̄2+ and Cu ̄2+ bylatosol, red soil and kaolinte coated with Mn oxide showed that Pb ̄2+ and Cu ̄2+ adsorption by all ...The study results of the effects of temperature and ionic strength on the adsorption kineties of Pb ̄2+ and Cu ̄2+ bylatosol, red soil and kaolinte coated with Mn oxide showed that Pb ̄2+ and Cu ̄2+ adsorption by all samples, as awhole, increased with missing temperature. Temperature also increased both values of X_m (the amount of ionadsorbed at equilibrium) and k (kinetica constant) of Pb ̄2+ and Cu ̄2+. The activation energies of Pb ̄2+ adsorption werekaolin-Mn >red soil>goethite and those of Cu ̄2+ were latosol> red soil > kaolin-Mn >goethite. For a given singlesample the activation energy of Cu ̄2+ was greater than that of Pb ̄2+. Raising ionic strength decreased the adsorptionof Pb ̄2+ and Cu ̄2+ by latosol, red soil and kaolinite coated with Mn oxide but increased Pb ̄2+ and Cu ̄2+ adsorption bygoethite. The contrary results could be explained by the different changes in ion forms of Pb ̄2+ or Cu ̄2+ and in surfacecbarge characteristics of latosol, red soil, kaolin-Mn and goethite. Increasing supporting electrolyte concentration in-creased X_m and k in goethite systems but decreased X_m and k in kaolin-Mn systems. All the time-dependent data fit-ted the surface second-order equation very well.展开更多
The adsorption difference of Pb^2_+ and Zn^2+ in sandstone andbreccia of Pb-Zn Mine of Yunnan Province was studied by using moderninstrument analysis method and fractal geometry theory. The resultsshow that the adsorp...The adsorption difference of Pb^2_+ and Zn^2+ in sandstone andbreccia of Pb-Zn Mine of Yunnan Province was studied by using moderninstrument analysis method and fractal geometry theory. The resultsshow that the adsorption capacity (Q) of Pb^2+ in this two rocks isbigger than that of Zn^2_+, and Q in various initial concentrationsolutions obeys Freundlich experiential formula. The value of 1/n onthe adsorption PB^2+ and Zn^2+ and Zn^2+ in sandstone hardly has anydifference, But the value of k differs observably.展开更多
In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The sc...In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities (qe) of Pb^2+ and Cd^2+ was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2+ and Cd^2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.展开更多
Pb2+ adsorption onto a soil by irrigation of sewage in the Pearl River Delta of South China was examined as a function of the reaction time, solution pH, initial lead concentration, organic matter (humic acid) and ...Pb2+ adsorption onto a soil by irrigation of sewage in the Pearl River Delta of South China was examined as a function of the reaction time, solution pH, initial lead concentration, organic matter (humic acid) and competitive ions (Cu2+). The adsorption of Pb2+ onto the soil was investigated on batch equilibrium adsorption experiments. Results show that the Pb2+ adsorption on the soil is relatively rapid in the first 30 min and reaches equilibrium at 2 h, and the kinetics of the adsorption process on the soil is well characterized by the pseudo-second order reaction rate. Langmuir, Freundlich and Temkin isothermal models are fit for the adsorption of Pb2+ onto the soil, and the maximum amount of Pb2+ adsorption (Qm) is 7.47 mg/g. The amount of Pb2+ adsorption increases with increasing the pH at the range of 1.2-4.5 and reaches a plateau at the range of 4.5-12. The presence of humic acid in soil decreases the adsorption of Pb2+ onto the soil at solution pH of 8 since the negatively charged humic acid with Pb2+ is difficult to be adsorbed on the negatively charged soil surface. The adsorption of Pb2+ onto the soil also decreases in the presence of Cu2+ due to file competition adsorption between Pb2+ and Cu2+.展开更多
The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% ...The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% of adsorption on all the samples occurred during the first 5 minutes.All adsorption time-dependent data could fit the surface second-order equation very well.The values of Xm were goethite>kaolinite,and latosol>red soil at the same initial reaction concentration.The values of k were kaolinite>>goethite,and latosol>red soil at the same reaction pH and initial concentration.The higher the suspension pH,the faster the adsorption occurred.The meaning of Xm got by the two ion-selective electrode technique(one kind of batch technique) was different from that by the miscible displacement technique in that the former was only the equilibrium adsorption amount at a definite concentration and pH,but the latter was almost equal to the adsorption capacity at a definite pH with much less influence of concentration.One Pb^2+ was supposed to occupy two adsorption sites as the adsorption mechanism is concerned.展开更多
Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of ...Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of heavy metal cations in leachate was determined with atomic absorption spectrophotometer. Their equilibrium isotherms were measured, and the experimental isotherm data were analyzed by using Freundlich and Langmuir models. The results show that the adsorption capacities of the heavy metal cations are closely related to the compositions of clay-solidified grouting curtain, and the maximum adsorption appears at the ratio of cement to clay of 2∶4 in the experimental conditions. At their maximum adsorption and pH 5.0, the adsorption capacities of Pb 2+ and Cd 2+ are 16.19mg/g and 1.21mg/g. The competitive adsorption coefficients indicate that the adsorption of clay-solidified grouting curtain for Pb2+ is stronger than that for Cd 2+ . The adsorption process conforms to Freundlich’s model with related coefficient higher than 0.996.展开更多
A new technique for studying the adsorption kinetics of heavy metals,Pb^2+ and Cu^2+,on variable charge surfaces was established with two selective electrodes and microcomputer control system.Feasibility of the techni...A new technique for studying the adsorption kinetics of heavy metals,Pb^2+ and Cu^2+,on variable charge surfaces was established with two selective electrodes and microcomputer control system.Feasibility of the technique,including interference of other ions (mainly Fe^3+ and Al^3+),response time of electrodes,and the pH range of testing,was studied.Comparision with the most widely used miscible displacement technique,which was considered insufficient in studying 30-minute rapid reactions,at present time showed that the new technique was more advantageous in testing in situ,easy to operate,and economic.展开更多
The adsorption properties of a novel macroporous weak acid resin (D152) for Pb^2+ were investigated with chemical methods. The optimal adsorption condition of D152 resin for Pb^2+ is at pH 6.00 in HAc-NaAc medium....The adsorption properties of a novel macroporous weak acid resin (D152) for Pb^2+ were investigated with chemical methods. The optimal adsorption condition of D152 resin for Pb^2+ is at pH 6.00 in HAc-NaAc medium. The statically saturated adsorption capacity is 527 mg/g at 298 K. Pb^2+ adsorbed on D152 resin can be eluted with 0.05 mol/L HCI quantitatively. The adsorption rate constants determined under various temperatures are k288 n=2.22×10-5 s^-1, k298 K=2.51 × 10^-5 s^-1, and k308 K= 2.95 × 10^-5 s^-1, respectively. The apparent activation energy, Ea is 10.5 kJ/mol, and the adsorption parameters of thermodynamics are ΔH^Θ=13.3 kJ/mol, ΔS^Θ=119 J/(mol·K), and ΔG^Θ298 K =-22.2 kJ/mol, respectively. The adsorption behavior of D152 resin for Pb^2+ follows Langmuir model.展开更多
A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(...A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)).The characteristics of CPM showed a porous structure,well dispersed MnFe_(2) O_(4),and several of hydroxyl and amino groups(-OH,-NH_(2)).Batch experiments demonstrated that the best adsorption property of As(Ⅲ),Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ) was achieved within 8 h with maximum adsorption capacities of 9.90,9.73,43.94,and 11.98 mg/g,respectively.Competitive and synergistic effects(particularly precipitation) were included in the co-adsorption mechanism of As(Ⅲ) and heavy metals.Thereinto,As(Ⅲ) was partly oxidized by MnFe_(2) O_(4) to As(V),and both were coordinated on MnFe_(2) O_(4) nanoparticles.Pb(Ⅱ) could also bind to MnFe_(2) O_(4) by ion exchange and electrostatic attraction.Furthermore,Cd(Ⅱ) and Cu(Ⅱ) tended to be coordinated on chitosan.Therefore,CPM can serve as a remediation material for water and soil co-contaminated with As(Ⅲ) and heavy metals.展开更多
A new di-function adsorbent (JN-3) was prepared by sulfhydryl modified. Comparing with Amberlite XAD-4 and NDA-150, the equilibrium adsorption for phenol on the JN-3 from aqueous solutions was tested, perfect adsorpti...A new di-function adsorbent (JN-3) was prepared by sulfhydryl modified. Comparing with Amberlite XAD-4 and NDA-150, the equilibrium adsorption for phenol on the JN-3 from aqueous solutions was tested, perfect adsorption capacity was shown. Pb2+ can be also removed by JN-3 because of the chelate interaction between sulfhydryl groups and metal ions. This adsorbent could be used in removal of combine pollutants such as phenolic compounds and heavy metal ions from waste streams.展开更多
The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings.The adsorption percentage of Pb2+ and Cd2+ ions as a funct...The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings.The adsorption percentage of Pb2+ and Cd2+ ions as a function of adsorbent dosage,solution pH value and shaking time were determined by batch experiments.The maximum adsorption percentage of 99.93% for Pb2+ ions and 99.75% for Cd2+ ions were obtained by using bauxite flotation tailings as adsorbent.The methods,such as zeta potentials,specific surface area measurements and the analysis of adsorption kinetics,were introduced to analyze the adsorption mechanisms of the Pb2+ ions on bauxite flotation tailings.The isoelectric point of bauxite flotation tailings shifts from 3.6 to 5.6 in the presence of Pb2+ ions.The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m2/g after the adsorption of Pb2+ ions.These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings.Adsorption data of Pb2+ ions on the surface of bauxite flotation tailings can be well described by Langmuir model,and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb2+ and Cd2+ ions on bauxite flotation tailings.展开更多
A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating r...A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating resin for Pb2+ were studied by batch adsorption, and the adsorption process was analyzed from thermodynamics and kinetics aspects. The adsorption mechanism of Pb2+ on the modified D401 chelating resin was discussed by FT-IR spectrometry. Experimental results show that in the Pb2+ concentration range of 200-400 mg/L, the adsorption capacities of the modified D401 chelating resin for Pb2+ increase by 77%-129%, and Langmuir isothermal adsorption model is more suitable for the equilibrium adsorption data. Adsorption is an endothermic process that runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best pH value under adsorption condition is 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the adsorption capacity remains stable after five consecutive adsorption-desorption cycles. The maximal static saturated adsorption capacity of the resin is 206 mg/g at 333 K in the Pb2+ concentration range of 200-400 mg/L. The modified D401 chelating resin is an efficient adsorbent for the removal of Pb2+ from its single-metal ion solution.展开更多
Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell (PAC) was used for...Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell (PAC) was used for the removal of Pb^2+ from aqueous solution. The impacts of the Pb25 adsorption capacities of the acid-modified carbons oxidized with HNO3 were also investigated. The surface functional groups of PAC were confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Boehm titration. The textural properties (surface area, total pore volume) were evaluated from the nitrogen adsorption isotherm at 77 K. The experimental results presented indicated that the adsorption data fitted better with the Langmuir adsorption model. A comparative study with a commercial granular activated carbon (GAC) showed that PAC was 10.3 times more efficient compared to GAC based on Langmuir maximum adsorption capacity. Further analysis results by the Langmuir equation showed that HNO3 [20% (by mass)] modified PAC has larger adsorption capacity of Pb^2+ from aqueous solution (as much as 35.5 mg·g^-1). The adsorption capacity enhancement ascribed to pore widening, increased cation-exchange capacity by oxygen groups, and the promoted hydrophilicity of the carbon surface.展开更多
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
基金financial support from the National Natural Science Foundation of China (Grant No.52004320)the Science Foundation of China University of Petroleum,Beijing (No.2462021QNXZ012,No.2462022BJRC001,and No.2462021YJRC012)the funding from the State Key Laboratory of Petroleum Resources and Engineering (No.PRP/indep-1-2103)。
文摘It is acknowledged that injecting CO_(2) into oil reservoirs and saline aquifers for storage is a practical and affordable method for CO_(2) sequestration.Most CO_(2) produced from industrial exhaust contains impurity gases such as H_(2)S that might impact CO_(2) sequestration due to competitive adsorption.This study makes a commendable effort to explore the adsorption behavior of CO_(2)/H_(2)S mixtures in calcite slit nanopores.Grand Canonical Monte Carlo(GCMC)simulation is employed to reveal the adsorption of CO_(2),H_(2)S as well as their binary mixtures in calcite nanopores.Results show that the increase in pressure and temperature can promote and inhibit the adsorption capacity of CO_(2) and H_(2)S in calcite nanopores,respectively.CO_(2)exhibits stronger adsorption on calcite surface than H_(2)S.Electrostatic energy plays the dominating role in the adsorption behavior.Electrostatic energy accounts for 97.11%of the CO_(2)-calcite interaction energy and 56.33%of the H_(2)S-calcite interaction energy at 10 MPa and 323.15 K.The presence of H_(2)S inhibits the CO_(2) adsorption in calcite nanopores due to competitive adsorption,and a higher mole fraction of H_(2)S leads to less CO_(2) adsorption.The quantity of CO_(2) adsorbed is lessened by approximately 33%when the mole fraction of H_(2)S reaches 0.25.CO_(2) molecules preferentially occupy the regions near the po re wall and H_(2)S molecules tend to reside at the center of nanopore even when the molar ratio of CO_(2) is low,indicating that CO_(2) has an adsorption priority on the calcite surface over H_(2)S.In addition,moisture can weaken the adsorption of both CO_(2) and H_(2)S,while CO_(2) is more affected.More interestingly,we find that pure CO_(2) is more suitable to be sequestrated in the shallower formations,i.e.,500-1500 m,whereas CO_(2)with H_(2)S impurity should be settled in the deeper reservoirs.
基金Supported by the National Natural Science Foundation of China(U19B6003)Sinopec Technology Research Project(P20077kxjgz)。
文摘In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.
基金supported by the Qingdao Postdoctoral Program Funding(QDBSH20220202045)Shandong provincial Natural Science Foundation(ZR2021ME049,ZR2022ME176)+1 种基金National Natural Science Foundation of China(22078176)Taishan Industrial Experts Program(TSCX202306135).
文摘In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.
基金supported by the National Natural Science Foundation of China (No. 20877036)
文摘Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(Ⅱ)-imprinted polymer for selective separation and enrichment of trace Pb(Ⅱ) from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray diffractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb(Ⅱ) from aqueous solutions on Pb(Ⅱ)-imprinted polymer. The equilibrium was achieved in approximately 4,0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb(Ⅱ) on Pb(Ⅱ)-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb(Ⅱ) from the Pb(Ⅱ)-imprinted polymer were also studied in batch experiments. The prepared Pb(Ⅱ)-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb(Ⅱ) from water samples. The adsorption and desorption mechanisms were proposed.
基金supported by the National Nature Science Foundation for Distinguished Young Scholars of China(No. 40425007)the National Natural Science Founda-tion of China (No. 40371062, 40771100)the Natural Science Foundation of Zhejiang Province (No. Y5080180)
文摘The combined pollution of heavy metal Pb^2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb^2+ was examined using high-performance liquid chromatograph (HPLC). Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) 〉 0.98, irrespective of the presence of spiked Pb^2+. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb^2+ concentration in soil which indicated that the spiked of Pb^2+ in paddy soils would promote the sorption of BSM. AGo of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter (DOM) enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb^2+ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.
文摘The study results of the effects of temperature and ionic strength on the adsorption kineties of Pb ̄2+ and Cu ̄2+ bylatosol, red soil and kaolinte coated with Mn oxide showed that Pb ̄2+ and Cu ̄2+ adsorption by all samples, as awhole, increased with missing temperature. Temperature also increased both values of X_m (the amount of ionadsorbed at equilibrium) and k (kinetica constant) of Pb ̄2+ and Cu ̄2+. The activation energies of Pb ̄2+ adsorption werekaolin-Mn >red soil>goethite and those of Cu ̄2+ were latosol> red soil > kaolin-Mn >goethite. For a given singlesample the activation energy of Cu ̄2+ was greater than that of Pb ̄2+. Raising ionic strength decreased the adsorptionof Pb ̄2+ and Cu ̄2+ by latosol, red soil and kaolinite coated with Mn oxide but increased Pb ̄2+ and Cu ̄2+ adsorption bygoethite. The contrary results could be explained by the different changes in ion forms of Pb ̄2+ or Cu ̄2+ and in surfacecbarge characteristics of latosol, red soil, kaolin-Mn and goethite. Increasing supporting electrolyte concentration in-creased X_m and k in goethite systems but decreased X_m and k in kaolin-Mn systems. All the time-dependent data fit-ted the surface second-order equation very well.
基金the Foundation on Predictive Research of Clamber Plan, China: 95-yu-39.3-2,2.
文摘The adsorption difference of Pb^2_+ and Zn^2+ in sandstone andbreccia of Pb-Zn Mine of Yunnan Province was studied by using moderninstrument analysis method and fractal geometry theory. The resultsshow that the adsorption capacity (Q) of Pb^2+ in this two rocks isbigger than that of Zn^2_+, and Q in various initial concentrationsolutions obeys Freundlich experiential formula. The value of 1/n onthe adsorption PB^2+ and Zn^2+ and Zn^2+ in sandstone hardly has anydifference, But the value of k differs observably.
基金Project(12JJ8016)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(CX2012B317)supported by Hunan Provincial Innovation Foundation For Postgraduate,ChinaProject(2006180)supported by the Hunan Key Discipline Construction Found of Environmental Science,China
文摘In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities (qe) of Pb^2+ and Cd^2+ was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2+ and Cd^2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.
基金Project(SK201109) supported by the Basic Scientific Study Funding from Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological SciencesProject(2010CB428806-2) supported by the National Basic Research Program of China
文摘Pb2+ adsorption onto a soil by irrigation of sewage in the Pearl River Delta of South China was examined as a function of the reaction time, solution pH, initial lead concentration, organic matter (humic acid) and competitive ions (Cu2+). The adsorption of Pb2+ onto the soil was investigated on batch equilibrium adsorption experiments. Results show that the Pb2+ adsorption on the soil is relatively rapid in the first 30 min and reaches equilibrium at 2 h, and the kinetics of the adsorption process on the soil is well characterized by the pseudo-second order reaction rate. Langmuir, Freundlich and Temkin isothermal models are fit for the adsorption of Pb2+ onto the soil, and the maximum amount of Pb2+ adsorption (Qm) is 7.47 mg/g. The amount of Pb2+ adsorption increases with increasing the pH at the range of 1.2-4.5 and reaches a plateau at the range of 4.5-12. The presence of humic acid in soil decreases the adsorption of Pb2+ onto the soil at solution pH of 8 since the negatively charged humic acid with Pb2+ is difficult to be adsorbed on the negatively charged soil surface. The adsorption of Pb2+ onto the soil also decreases in the presence of Cu2+ due to file competition adsorption between Pb2+ and Cu2+.
基金Project supported by the National Natural Science Foundation of China.
文摘The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% of adsorption on all the samples occurred during the first 5 minutes.All adsorption time-dependent data could fit the surface second-order equation very well.The values of Xm were goethite>kaolinite,and latosol>red soil at the same initial reaction concentration.The values of k were kaolinite>>goethite,and latosol>red soil at the same reaction pH and initial concentration.The higher the suspension pH,the faster the adsorption occurred.The meaning of Xm got by the two ion-selective electrode technique(one kind of batch technique) was different from that by the miscible displacement technique in that the former was only the equilibrium adsorption amount at a definite concentration and pH,but the latter was almost equal to the adsorption capacity at a definite pH with much less influence of concentration.One Pb^2+ was supposed to occupy two adsorption sites as the adsorption mechanism is concerned.
基金Project (200065) supported by University Key Teacher Foundation of the Ministry of Education of China
文摘Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of heavy metal cations in leachate was determined with atomic absorption spectrophotometer. Their equilibrium isotherms were measured, and the experimental isotherm data were analyzed by using Freundlich and Langmuir models. The results show that the adsorption capacities of the heavy metal cations are closely related to the compositions of clay-solidified grouting curtain, and the maximum adsorption appears at the ratio of cement to clay of 2∶4 in the experimental conditions. At their maximum adsorption and pH 5.0, the adsorption capacities of Pb 2+ and Cd 2+ are 16.19mg/g and 1.21mg/g. The competitive adsorption coefficients indicate that the adsorption of clay-solidified grouting curtain for Pb2+ is stronger than that for Cd 2+ . The adsorption process conforms to Freundlich’s model with related coefficient higher than 0.996.
基金Project supported by the National Naturai Science Foundation of China
文摘A new technique for studying the adsorption kinetics of heavy metals,Pb^2+ and Cu^2+,on variable charge surfaces was established with two selective electrodes and microcomputer control system.Feasibility of the technique,including interference of other ions (mainly Fe^3+ and Al^3+),response time of electrodes,and the pH range of testing,was studied.Comparision with the most widely used miscible displacement technique,which was considered insufficient in studying 30-minute rapid reactions,at present time showed that the new technique was more advantageous in testing in situ,easy to operate,and economic.
基金Project(2008F70059) supported by the Scientific and Technological Research Planning of Zhejiang Province, China
文摘The adsorption properties of a novel macroporous weak acid resin (D152) for Pb^2+ were investigated with chemical methods. The optimal adsorption condition of D152 resin for Pb^2+ is at pH 6.00 in HAc-NaAc medium. The statically saturated adsorption capacity is 527 mg/g at 298 K. Pb^2+ adsorbed on D152 resin can be eluted with 0.05 mol/L HCI quantitatively. The adsorption rate constants determined under various temperatures are k288 n=2.22×10-5 s^-1, k298 K=2.51 × 10^-5 s^-1, and k308 K= 2.95 × 10^-5 s^-1, respectively. The apparent activation energy, Ea is 10.5 kJ/mol, and the adsorption parameters of thermodynamics are ΔH^Θ=13.3 kJ/mol, ΔS^Θ=119 J/(mol·K), and ΔG^Θ298 K =-22.2 kJ/mol, respectively. The adsorption behavior of D152 resin for Pb^2+ follows Langmuir model.
基金funded by the National Key Research and Development Project (No. 2020YFC1807700)the National Key Research and Development Project (No. 2019YFC1805900)+4 种基金the Youth Fund Project of GRINM (No. 12008)the Youth Fund Project of GRINM (No. 12119)the Open Foundation of State Key Laboratory of Mineral Processing (No. BGRIMM-KJSKL-2020-07)the Open Foundation of State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization (No. 2021P4FZG13A)the National Natural Science Foundation of China (No. 51704028)。
文摘A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)).The characteristics of CPM showed a porous structure,well dispersed MnFe_(2) O_(4),and several of hydroxyl and amino groups(-OH,-NH_(2)).Batch experiments demonstrated that the best adsorption property of As(Ⅲ),Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ) was achieved within 8 h with maximum adsorption capacities of 9.90,9.73,43.94,and 11.98 mg/g,respectively.Competitive and synergistic effects(particularly precipitation) were included in the co-adsorption mechanism of As(Ⅲ) and heavy metals.Thereinto,As(Ⅲ) was partly oxidized by MnFe_(2) O_(4) to As(V),and both were coordinated on MnFe_(2) O_(4) nanoparticles.Pb(Ⅱ) could also bind to MnFe_(2) O_(4) by ion exchange and electrostatic attraction.Furthermore,Cd(Ⅱ) and Cu(Ⅱ) tended to be coordinated on chitosan.Therefore,CPM can serve as a remediation material for water and soil co-contaminated with As(Ⅲ) and heavy metals.
基金The National Natural Science Foundation of China (No.50778088).
文摘A new di-function adsorbent (JN-3) was prepared by sulfhydryl modified. Comparing with Amberlite XAD-4 and NDA-150, the equilibrium adsorption for phenol on the JN-3 from aqueous solutions was tested, perfect adsorption capacity was shown. Pb2+ can be also removed by JN-3 because of the chelate interaction between sulfhydryl groups and metal ions. This adsorbent could be used in removal of combine pollutants such as phenolic compounds and heavy metal ions from waste streams.
基金Project(2005CB623701) supported by the Major State Basic Research Development Program of China
文摘The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings.The adsorption percentage of Pb2+ and Cd2+ ions as a function of adsorbent dosage,solution pH value and shaking time were determined by batch experiments.The maximum adsorption percentage of 99.93% for Pb2+ ions and 99.75% for Cd2+ ions were obtained by using bauxite flotation tailings as adsorbent.The methods,such as zeta potentials,specific surface area measurements and the analysis of adsorption kinetics,were introduced to analyze the adsorption mechanisms of the Pb2+ ions on bauxite flotation tailings.The isoelectric point of bauxite flotation tailings shifts from 3.6 to 5.6 in the presence of Pb2+ ions.The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m2/g after the adsorption of Pb2+ ions.These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings.Adsorption data of Pb2+ ions on the surface of bauxite flotation tailings can be well described by Langmuir model,and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb2+ and Cd2+ ions on bauxite flotation tailings.
基金Project(708049) supported by the Important Item Cultivation Foundation of Scientific Innovation Project of Colleges and Universities of China
文摘A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating resin for Pb2+ were studied by batch adsorption, and the adsorption process was analyzed from thermodynamics and kinetics aspects. The adsorption mechanism of Pb2+ on the modified D401 chelating resin was discussed by FT-IR spectrometry. Experimental results show that in the Pb2+ concentration range of 200-400 mg/L, the adsorption capacities of the modified D401 chelating resin for Pb2+ increase by 77%-129%, and Langmuir isothermal adsorption model is more suitable for the equilibrium adsorption data. Adsorption is an endothermic process that runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best pH value under adsorption condition is 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the adsorption capacity remains stable after five consecutive adsorption-desorption cycles. The maximal static saturated adsorption capacity of the resin is 206 mg/g at 333 K in the Pb2+ concentration range of 200-400 mg/L. The modified D401 chelating resin is an efficient adsorbent for the removal of Pb2+ from its single-metal ion solution.
文摘Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell (PAC) was used for the removal of Pb^2+ from aqueous solution. The impacts of the Pb25 adsorption capacities of the acid-modified carbons oxidized with HNO3 were also investigated. The surface functional groups of PAC were confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Boehm titration. The textural properties (surface area, total pore volume) were evaluated from the nitrogen adsorption isotherm at 77 K. The experimental results presented indicated that the adsorption data fitted better with the Langmuir adsorption model. A comparative study with a commercial granular activated carbon (GAC) showed that PAC was 10.3 times more efficient compared to GAC based on Langmuir maximum adsorption capacity. Further analysis results by the Langmuir equation showed that HNO3 [20% (by mass)] modified PAC has larger adsorption capacity of Pb^2+ from aqueous solution (as much as 35.5 mg·g^-1). The adsorption capacity enhancement ascribed to pore widening, increased cation-exchange capacity by oxygen groups, and the promoted hydrophilicity of the carbon surface.