高炉渣对废水中Cu~(2+)吸附性能的研究

用高炉渣吸附废水中的Cu⁽²⁺⁾,探讨了反应时间、吸附剂投加量、吸附温度和废水pH等因素对废水中Cu(2+),探讨了反应时间、吸附剂投加量、吸附温度和废水pH等因素对废水中Cu⁽²⁺⁾去除率的影响,并从动力学和等温吸附模型探讨了吸附作用机理。结果表明,当吸附温度为室温(25℃)、吸附剂投加量为1.2 g、反应时间为60 min、废水初始pH为7时,Cu(2+)去除率的影响,并从动力学和等温吸附模型探讨了吸附作用机理。结果表明,当吸附温度为室温(25℃)、吸附剂投加量为1.2 g、反应时间为60 min、废水初始pH为7时,Cu⁽²⁺⁾去除率达95.18%;高炉渣吸附剂对废水中Cu(2+)去除率达95.18%;高炉渣吸附剂对废水中Cu⁽²⁺⁾的吸附过程符合吸附伪二级动力学方程和Langmuir吸附等温模型,这表明此吸附过程主要是单分子层吸附,并且吸附是容易发生的。     

改性海泡石吸附低浓度Ni(Ⅱ)-CA的研究

利用3-氨丙基三乙氧基硅烷对海泡石进行改性,用于吸附柠檬酸络合镍(Ni(Ⅱ)-CA)废水,考察了初始pH、吸附剂用量、吸附时间及初始浓度对柠檬酸镍吸附性能的影响,并结合吸附动力学和等温吸附模型对其分析。结果表明,Ni(Ⅱ)-CA浓度为5 mg/L,加入12 g/L吸附剂,pH为6时,室温下反应40 min左右达到平衡,改性海泡石对柠檬酸镍的去除率与吸附量分别为96. 24%和0. 401 mg/g。经过改性后的海泡石吸附能力有较大提高,最大吸附量从0. 619 mg/g提升至1. 116 mg/g,提高了80%。准二级动力学模型和Langmuir等温吸附模型能较好地描述海泡石和改性海泡石对柠檬酸镍的吸附过程。     

改性海泡石吸附低浓度Ni(Ⅱ)-CA的研究

利用3-氨丙基三乙氧基硅烷对海泡石进行改性,用于吸附柠檬酸络合镍(Ni(Ⅱ)-CA)废水,考察了初始pH、吸附剂用量、吸附时间及初始浓度对柠檬酸镍吸附性能的影响,并结合吸附动力学和等温吸附模型对其分析。结果表明,Ni(Ⅱ)-CA浓度为5 mg/L,加入12 g/L吸附剂,pH为6时,室温下反应40 min左右达到平衡,改性海泡石对柠檬酸镍的去除率与吸附量分别为96. 24%和0. 401 mg/g。经过改性后的海泡石吸附能力有较大提高,最大吸附量从0. 619 mg/g提升至1. 116 mg/g,提高了80%。准二级动力学模型和Langmuir等温吸附模型能较好地描述海泡石和改性海泡石对柠檬酸镍的吸附过程。     

硫酸改性松树叶对废水中Cr(Ⅵ)的吸附性能研究

以松树叶为原料,经硫酸改性制得吸附剂,通过吸附实验考察了pH、吸附时间、初始质量浓度及吸附剂用量对Cr(Ⅵ)的影响。结果表明,在50mL质量浓度为10.0mg/L的Cr(Ⅵ)溶液中,吸附剂用量0.4g,pH=3,吸附t为120min时,效果最佳,Cr(Ⅵ)的吸附量可达1.22mg/g,去除率达到97.6%。对实验数据进行吸附动力学模型进行拟合,结果表明,吸附过程更符合准二级动力学模型,以化学吸附为主。     

高吸水性树脂Super-Ⅰ对Pb~(2+)的吸附性能

考察了聚(丙烯酸—co—丙烯酰胺)/凹凸棒黏土高吸水性树脂吸附剂(标记为Super-Ⅰ)对重金属Pb2+的吸附行为及溶液pH(3.0~7.0)、吸附时间(0~720 m in)、Pb2+溶液初始浓度(0.002 5~0.03 mol/L)和吸附剂加入量(0.08~0.30 g)等因素对吸附性能的影响。在pH=6.0、吸附时间60 m in、Pb2+溶液初始浓度0.02 mol/L和吸附剂用量0.1 g条件下,该吸附剂对Pb2+的吸附量达到296.0 mg/g。高吸水性树脂吸附剂对Pb2+的吸附行为符合准二级动力学模型和Langmu ir等温线模型。与常用多孔吸附剂相比,该三维网络吸附剂对Pb2+的吸附量高出1~2个数量级。     

蒙脱土/聚丙烯硫脲复合材料对铬(VI)吸附行为

制备了蒙脱土/聚丙烯硫脲复合材料,考察了该材料对Cr(VI)的吸附能力,研究了震荡时间、吸附剂用量、溶液的pH值、温度对吸附剂吸附量的影响.实验结果表明:在313 K的温度下,吸附剂用量为20 mg,震荡时间为3 h, pH=1时,最大吸附量可达53.13 mg/g.该等温吸附过程可以用Langmuir方程进行较好拟合,动力学研究表明Cr(VI)在蒙脱土/聚丙烯硫脲上的吸附机理符合二级动力学.     

高炉渣对碱性品蓝吸附性能的研究

本试验研究了高炉渣对碱性品蓝的吸附性能,借助电镜扫描(SEM)技术对吸附剂进行了表征,探讨了碱性品蓝的初始浓度、吸附时间、吸附剂投加量、吸附温度、离子强度和废水pH等因素对碱性品蓝去除率的影响,并从动力学和等温吸附模型探讨了吸附作用机理.实验结果表明:当吸附温度为室温(25℃)、吸附剂加入量为0.4g、吸附时间为120 min、废水pH为8、初始碱性品蓝浓度为100 mg/L、离子强度为0 mol/L时,碱性品蓝去除率达78.31％;高炉渣对碱性品蓝的吸附符合伪二级动力学方程和Freundlich等温吸附模型,并且吸附是容易发生的.     

大孔吸附树脂XAD-4对聚乙二醇的吸附性能

以大孔吸附树脂XAD-4为吸附剂,采用静态平衡吸附法吸附模拟聚乙二醇(PEG)废水,考察了初始pH值、吸附时间、吸附剂投加量和温度等因素对PEG去除效果的影响. 结果表明,pH值对吸附过程的影响可忽略不计. 当XAD-4树脂投加量为0.3 g/L时,PEG去除率可达89%,平衡吸附量Qe=59.95 mg/g. PEG在XAD-4树脂表面上均一分布,Langmuir, Dubinin-Radushkevich和Sips模型可较好地模拟其等温吸附过程. 不同温度下均为自发的放热吸附过程. 动态吸附数据符合拟二级动力学方程.     

改性香蕉皮对Cr(Ⅵ)的吸附研究

以香蕉皮(BP)为原料,脱色后通过3-氯-2-羟丙基三甲基氯化铵改性制备新型香蕉皮生物吸附剂MBP。采用扫描电镜对吸附剂进行表征。经改性后,同等条件下MBP比BP的吸附量提高。考察溶液pH、吸附剂用量、金属离子浓度和吸附时间对其从水溶液中吸附Cr(Ⅵ)的吸附性能的影响。结果表明,最佳的溶液pH值为2.0,最佳吸附剂用量4-5 g/L。MBP对Cr(Ⅵ)的吸附量随溶液中金属离子浓度的增加而增加,吸附等温线符合Langmuir单分子层吸附模型,MBP在40℃对Cr(Ⅵ)的最大吸附量为58.82 mg/g;MBP对Cr(Ⅵ)的吸附,在150 min时基本上达到吸附平衡,吸附动力学符合准二级动力学方程。     

颗粒化坡缕石表征及对Pb~(2+)的吸附特性

坡缕石黏土进行简单提纯后,和海藻酸钠、纯水充分混合(物料比为坡缕石∶海藻酸钠∶水=100 g∶9 g∶77 m L),并在潮湿密闭环境下浸润24 h,制成粒径5 mm颗粒。(105±2)℃干燥后,焙烧2 h,制备颗粒状坡缕石吸附剂,采用XRD、BET进行表征,通过静态吸附实验探讨了pH值、Pb⁽²⁺⁾初始浓度、反应时间和反应温度对吸附的影响,确立了颗粒化吸附剂对Pb(2+)初始浓度、反应时间和反应温度对吸附的影响,确立了颗粒化吸附剂对Pb⁽²⁺⁾的吸附动力学和吸附等温线。结果表明,在颗粒化后,坡缕石黏土主要XRD衍射峰得以保留;600℃下烧结,使比表面积降低,而孔容积增大。随着pH值增大,坡缕石颗粒吸附剂对Pb(2+)的吸附动力学和吸附等温线。结果表明,在颗粒化后,坡缕石黏土主要XRD衍射峰得以保留;600℃下烧结,使比表面积降低,而孔容积增大。随着pH值增大,坡缕石颗粒吸附剂对Pb⁽²⁺⁾的吸附量增加;随着初始浓度的增加,颗粒吸附剂对Pb(2+)的吸附量增加;随着初始浓度的增加,颗粒吸附剂对Pb⁽²⁺⁾的吸附去除率逐渐降低,平衡吸附量则逐渐上升。当pH值为5.0,Pb(2+)的吸附去除率逐渐降低,平衡吸附量则逐渐上升。当pH值为5.0,Pb⁽²⁺⁾初始浓度2 500 mg/L时,平衡吸附量达59.85 mg/g。吸附动力学符合颗粒内扩散模型。颗粒化坡缕石吸附剂对Pb(2+)初始浓度2 500 mg/L时,平衡吸附量达59.85 mg/g。吸附动力学符合颗粒内扩散模型。颗粒化坡缕石吸附剂对Pb⁽²⁺⁾的吸附符合Langmuir吸附等温式,属于吸热反应。     

Equilibrium,Kinetics, and Thermodynamics of Bovine Serum Albumin Adsorption on Single-Walled Carbon Nanotubes

We investigated the equilibrium, kinetics, and thermodynamics of bovine serum albumin (BSA) adsorption on single-walled carbon nanotubes (SWNTs) from aqueous solutions with different pH and temperatures. We analyzed the experimental adsorption equilibrium and kinetic data to evaluate the adsorption characteristics of SWNTs for BSA. The results show that the effects of pH and temperature were important. Moreover, the adsorption isotherm data of BSA on SWNTs are consistent with the Langmuir and Freundlich models, while the kinetics can be expressed by the pseudo-first-order and the intraparticle diffusion rate models. The maximum protein adsorption capacity of SWNTs, which have a surface area of 191.2 m²/g, was found to be 609.8 mg g^?1 at pH 4 and 40°C, and this was the highest value obtained among our previous studies examined with various metal oxides. In addition, the zeta potential measurements were examined to understand the effects of charge density of the surface and the protein on the adsorption process. Thermodynamic analysis results indicate that the nature of adsorption changes with pH. SWNTs were found to be effective for BSA adsorption.     

污泥转移SBR工艺中EPS对生物除磷的作用

采用新型强化生物除磷工艺--污泥转移SBR处理合成废水,探讨胞外聚合物（EPS）在工艺强化除磷过程中的作用。当污泥转移量为0、15%及30%时,污泥中的EPS含量分别为（108.14±9.68）mg·（g MLSS）^-1、（128.17±1.45）mg·（g MLSS）^-1和（123.35±22.98）mg·（g MLSS）^-1;工艺的除磷率分别为82.14%±0.85%、96.35%±1.25%及98.99%±0.98%,反应末端EPS中TP含量占污泥中TP的比重分别为27.9%±2.55%、57.23%±2.33%和63.88%±2.87%。此外,污泥中EPS在该工艺的好氧吸磷过程中吸磷量分别为（2.04±0.32）mg·（g MLSS）^-1、（5.90±0.38）mg·（g MLSS）^-1和（6.00±0.52）mg·（g MLSS）^-1,在污泥吸磷量中的贡献率均达到90%以上。研究结果表明：污泥转移SBR工艺中随着污泥转移量的增大有利于提高EPS中的磷含量,从而提升了工艺的除磷性能,EPS在该工艺的吸磷过程中起主要作用。但污泥转移对污泥中EPS含量影响不显著。     

剩余污泥吸附痕量典型药物影响因素

传统的污水处理工艺不能完全去除药物和个人护理用品（PPCPs）,可能通过吸附作用存在于剩余污泥中。当污泥经土地或农业利用,其中含有的PPCPs可能释放出来,污染水环境,因此,揭示PPCPs经污泥吸附去除的影响因素,对于预测或评估污泥中PPCPs含量尤其重要。以北京某污水处理厂剩余污泥为对象,利用高效液相色谱-质谱联用仪,研究了痕量浓度下3种典型药物在污泥中的赋存特性。随pH增大,环丙沙星与磺胺甲唑的吸附容量减小,而扑热息痛的吸附容量增加;主要是因为pH不仅改变药物在水中的存在形态,而且影响微生物细胞体的表面电位。胞外聚合物（EPS）对污泥吸附3种典型药物均有促进作用,且不依赖于pH;主要是因为EPS中含有的金属离子与有机物成分决定污泥吸附药物性能。     

Adsorption behavior of L-tryptophan on ion exchange resin

A batch method was applied to investigate the adsorption behavior and mechanisms of L-tryptophan (L-trp) on ion exchange resins. HZ-001 and JK006 were proved to be ideal adsorbents due to their large loading capacityand favorable selective adsorption for L-trp. Langmuir, Freundlich, and Dubinin-Radushkevich equations were appliedto simulate the experimental data to describe the adsorption process of L-trp onto HZ-001 and JK006. The maximumloading capacity (at pH 5.0, 30 °C), determined by the Langmuir and Dubinin-Radushkevich models, was close to eachother (833 mg/g vs. 874 mg/g) for HZ-001, while discrepant (833 mg/g vs. 935 mg/g) for JK006. Three diffusion-controlled kinetic models were utilized to analyze the results in order to identify the adsorption mechanism. The adsorptionkinetics of L-trp onto cation exchange resins was investigated under different experimental conditions, including initialsolution pH, temperature, initial L-trp concentration, and adsorbent dosage. Moreover, the diffusion process of L-trponto HZ-001 and JK006 was evaluated at different initial adsorbate concentrations. The thermodynamic parameters, obtained from the kinetic data, demonstrated that L-trp could be adsorbed spontaneously onto both resins.     

Adsorption of chromium(VI) from aqueous solutions onto amine-functionalized natural and acid-activated sepiolites

Chromium(VI) adsorption onto amine-functionalized sepiolites from aqueous solution at 298 K was investigated. Natural and acid-activated sepiolites were functionalized by covalent grafting [3-(2-aminoethylamino)propyl]trimethoxy-silane to the silanol groups onto the sepiolite surface. Functionalization was proved by differential thermal analysis and the point of zero charge, pH_pzc, determinations. The adsorption isotherms suggested that the adsorption capacity of the functionalized acid-activated sepiolite was higher than that of the functionalized natural sepiolite, for all investigated initial solution pH values. Adsorption efficiency of the functionalized sepiolites was improved by decreasing solution pH value. Due to the high value of pH_pzc and large buffer capacity of adsorbents, a very low initial solution pH value was required to achieve high protonation of the surface amine groups and provide electrostatic attraction of Cr(VI) anionic species. The maximum chromium(VI) removal was achieved at an initial pH of 2.0; ca. 60 mg/g of functionalized acid-activated sepiolite and ca. 37 mg/g of functionalized natural sepiolite. Equilibrium data for both functionalized sepiolites at an initial solution pH value of 2.0 fitted well to the Freundlich model. The adsorption process followed pseudo-second-order kinetics. The values of the thermodynamic parameters indicate a spontaneous adsorption process of a prevalently physical nature.     

Adsorption of bark derived polyphenols onto functionalized nanocellulose: Equilibrium modeling and kinetics

This article describes the kinetics and capacity of adsorbing condensed conifer tannins onto cationic cellulose nanocrystals (CCNCs). Batch adsorption experiments were carried as a function of pH, contact time, and initial tannin concentration with constant cationic cellulose nanocrystal concentration (0.01%). The adsorption process was highly pH dependent as adsorption capacities ranged from 13.2 mg/g to 112.7 mg/g at pH of 3–10. The amount of tannin adsorbed per unit mass of the cationic cellulose nanocrystals increased with increasing of tannin concentration until equilibrium was attained. The experimental data followed the Langmuir adsorption model, and the maximum experimental and theoretical adsorption capacities for the cationic nanocrystals reached 1,008 mg/g and 1,111 mg/g, respectively. The kinetics of adsorption was described best by the pseudo-second-order kinetics indicating a chemisorption process. The inherent adsorption has interesting applications for CCNC-complexes with natural polyphenolics in green chemical applications for adhesives, adsorbents, preservatives, and packaging materials.     

Modification of Sodium Alginate for the Removal of Cd(II) from Aqueous Solutions

Sodium alginate was protonated using HCl in ethanol: H₂O mixture (30:70). The modified sodium alginate (MSA) was characterized by determination of carboxyl content and solubility percent. The modified sample acquires of 450 meq-COOH/100 g sample and exhibits the complete insolubility in water. The MSA was utilized as adsorbent material to remove Cd(II) ions from aqueous solutions. Factors affecting adsorption process, such as agitation time and adsorbent concentration and pH of the adsorbate, were examined. The adsorption data show that the maximum adsorption capacity, Q_max, of Cd(II) onto MSA is 769.23 mg/g. The adsorption data also showed that the adsorption of Cd(II) onto MSA obeys Langmuir and Freundlich isotherms.     

Adsorption of Lignosulfonate Compound from Aqueous Solution onto Chitosan-Silica Beads

The main objective of this study is to investigate the possibility of crosslinked chitosan-tetraethoxy orthosilane (TEOS) (chitosan-silica) beads to be used as an adsorbent material to adsorb the lignosulfonate compound in solution. Different parameters affecting the adsorption capacity such as contact time, adsorbent dosage, initial concentration, pH, ionic strength, and temperature have been investigated. Adsorption isotherms of lignosulfonates onto chitosan-silica beads were also studied. Batch adsorption experiments were carried out and the optimum lignosulfonate adsorption onto chitosan-silica beads occurred at contact time of 30 minutes, the adsorbent dosage of 40 g/L, initial concentration of 50 mg/L, pH 5, and a temperature of 45°C. Adsorption isotherms studied through the use of graphical methods revealed that the adsorption of lignosulfonates onto chitosan-silica beads follows the Langmuir model, with the maximum adsorption capacity being 238.3 mg/g at pH 7. Adsorption is dependent on the ionic strength. The adsorption of lignosulfonate on chitosan-silica beads was best described with the pseudo-second-order kinetic model with a rate constant of 0.32 g · mg^?1 · min^?1, while intra-particle-diffusion was the main rate-determining step in the lignosulfonate adsorption process. The chitosan-silica beads investigated in this study were thus exhibited as a high potential adsorbent for the removal of lignosulfonate from solution.     

Adsorption characterization of lead(II) and cadmium(II) on crosslinked carboxymethyl starch

The adsorption of Pb(II) and Cd(II) ions with crosslinked carboxymethyl starch (CCS) was investigated as function of the solution pH, contact time, initial metal‐ion concentration, and temperature. Isotherm studies revealed that the adsorption of metal ions onto CCS better followed the Langmuir isotherm and the Dubinin–Radushkevich isotherm with adsorption maximum capacities of about 80.0 and 47.0 mg/g for Pb(II) and Cd(II) ions, respectively. The mean free energies of adsorption were found to be between 8 and 16 kJ/mol for Pb(II) and Cd(II) ions; this suggested that the adsorption of Pb(II) and Cd(II) ions onto CCS occurred with an ion‐exchange process. For two‐target heavy‐metal ion adsorption, a pseudo‐second‐order model and intraparticle diffusion seem significant in the rate‐controlling step, but the pseudo‐second‐order chemical reaction kinetics provide the best correlation for the experimental data. The enthalpy change for the process was found to be exothermic, and the ΔS^θ values were calculated to be negative for the adsorption of Pb(II) and Cd(II) ions onto CCS. Negative free enthalpy change values indicated that the adsorption process was feasible. The studies of the kinetics, isotherm, and thermodynamics indicated that the adsorption of CCS was more effective for Pb(II) ions than for Cd(II) ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Comparison of Basic Dye Crystal Violet Removal from Aqueous Solution by Low-Cost Biosorbents

Abstract

The removal of basic dye crystal violet by low-cost biosorbents was investigated in this study using a batch experimental system. The adsorption of crystal violet onto various adsorbents was solution pH-dependent and the maximum removal occurred at basic pH 10.0. The kinetic experimental data were analyzed using pseudo-first-order and pseudo-second-order equations to examine the adsorption mechanism and the intraparticle diffusion model to identify the potential rate controlling step. These results suggested that the adsorption of crystal violet onto various adsorbents was best represented by the pseudo-second-order equation. The suitability of the Langmuir and Freundich adsorption isotherms to the equilibrium data was also investigated at various temperatures for all four sorbents and the adsorption isotherms exhibited Freundlich behavior. The Freundlich constant K_f was 1.55 for alligator weed, 2.33 for Laminaria japonica, 9.59 for rice bran and 5.38 (mg/g)/(mg/L)^1/n for wheat bran, respectively at adsorbent concentration 5 g/L, pH 10.0 and 20°C. The thermodynamic parameters (ΔH, ΔG, and ΔS) were calculated and the results showed that the adsorption process for various adsorbents was spontaneous, endothermic, with an increased randomness, respectively. The particle size and the reaction temperature exhibited an insignificant impact on the adsorption equilibrium of crystal violet. The adsorbents investigated could serve as low-cost adsorbents for removing the crystal violet from aqueous solution.