Adsorption and removal of cadmium （ Ⅱ ） from aqueous solutions by bio-formulation

A novel sorbent, bio-formulation（BF）, was prepared and employed for the adsorption of cadmium（Cd） ion from aqueous system. The process of adsorption follows the pseudo second-order kinetic equation and the adsorption behavior is fitted with a Freundlich isotherm. The removal rate of Cd is slightly dependent on the initial pH value over a wide range of 4-11. The addition of Zn^2＋ and Cu^2＋ ions hardly affects the Cd adsorption, whereas the coexisting Pb^2＋ ion greatly interferes with the adsorption. The adsorption mechanism is supposed as a cation-exchange process between Cd^2＋ and calcium and Mg^2＋ present on the surface of BF, and somewhat as adsorption in a hydrolyzed form. The adsorbed Cd ions are desorbed effectively by a 0.1 mol/L HCl solution.     

Pannonibacter phragmitetus T1菌对pb2+的吸附特性

以pannonibacter phragmitetusT1菌作为生物吸附剂,研究细菌代谢活性、培养时间、溶液pH值、菌体用量、温度、吸附时间、初始金属浓度等因素对其吸附重金属pb2+的影响,并进一步研究吸附机理.结果表明,培养12h的灭活T1菌体在pb2+浓度为150 mg/L、pH值为6、T1菌添加量为0.5 g/L、温度为30℃的条件下,对Pb2+的最大吸附量为68.35 mg/g;灭活T1菌对重金属Pb2+的吸附过程较快,90 min即达到吸附平衡,pb2+的吸附符合Pseudo-second order模型和Langmuir等温吸附模型.结合红外光谱分析,灭活pannonibacter phragmitetus T1 菌对Pb2+是表面吸附,羟基和酰胺基是与Pb2+络合反应的主要基团.     

Biosorption behaviors of Cu~(2 ),Zn~(2 ),Cd~(2 ) and mixture by waste activated sludge

1Introduction Waste activated sludge is the by-product of sewage treated by activated sludge process.According to incomplete statistic,in China sewage discharge amount is4.474×107m3/d[1],and there are more than100sewage treatment plants with different sc…     

Efficiency,mechanism and microbial community of Cd(II) removal by mixed bacteria enriched from heavy metals mine soil

Mixed bacteria were enriched from heavy metals mine soil for cadmium (Cd(II))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(II) concentration, and biomass dosage were 6.0, 30 °C, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(II) removal efficiency (91.97%) than autoclaved biomass (79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(II) adsorption process, while XRD results showed that crystalline Cd(OH)₂ and CdO were obtained. After Cd(II)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas (39.94%), unclassified_f__Enterobacteriaceae (34.96%), Ochrobactrum (14.07%), Alcaligenes (4.84%), Bordetella (2.07%), Serratia (1.04%), and Bacillus (1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(II)-containing wastewater treatment.     

壳聚糖固定化枯草芽孢杆菌水溶液中铜离子的吸附(英文)

研究了壳聚糖固定化枯草芽孢杆菌吸附铜离子的性能,分析了pH、吸附剂投加量、温度、铜离子初始浓度和时间对铜离子吸附的影响。结果表明,pH对铜离子的吸附有较大的影响。此外,固定化枯草芽孢杆菌吸附剂比空白吸附剂具有更强的吸附性能。整个吸附过程符合朗缪尔吸附模型(R2=0.994),最大吸附量为100.70mg/L。动力学模型拟合结果表明,实验符合准二级动力学模型,线性相关指数大于0.999。吸附剂能在0.1mol/LNaOH溶液中被成功解吸。     

一株抗镉真菌的分类学鉴定和镉吸附

研究一株高抗镉真菌M1的分类学鉴定和镉吸附影响因素。通过分子生物学方法获得ITS 和β-微管蛋白的基因序列,并进行测序和分析;采用摇瓶振荡培养方法研究影响镉生物吸附能力的因素;采用傅里叶红外光谱对菌丝的镉吸附机理进行初步分析。基因序列相似性比较和系统发育树构建均表明该真菌与淡紫拟青霉的关系最近,表明真菌M1在分类学上属于淡紫拟青霉菌。活的和失活菌丝体分别在起始pH值为6~7和5~7的范围内表现出较好的吸附能力,镉溶液浓度为100 mg/L 时吸附效率最好。锌和锰对菌体的镉吸附有些许影响,而铜和铅对它的镉吸附影响明显。红外光谱分析表明：菌体吸附镉主要与羰基、羟基和氨基等基团有关。实验结果表明：真菌M1在重金属的生物修复中具有较好的应用前景。     

Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.     

普罗维登斯菌和希瓦氏菌对Pt(IV)的吸附特性

研究了普罗维登斯菌和希瓦氏菌两种微生物对Pt(IV)的吸附特性。pH和离子强度条件优化实验结果表明,pH=2.0时吸附效果较好,吸附量分别为58.62和72.20 mg/g;随着离子强度的增加,普罗维登斯菌对Pt(IV)的吸附量增加而希瓦氏菌却降低;Pt(IV)和Pd(II)共存时,两种微生物吸附剂均优先吸附Pd(II)。动力学和等温吸附实验结果表明,普罗维登斯菌吸附Pt(IV)的过程更符合拟二级动力学模型和Langmuir等温模型,说明化学吸附是该过程的限速步骤,且为单分子层吸附,其理论最大吸附量为136.10 mg/g。因此,以上研究结果表明,普罗维登斯菌和希瓦氏菌可以吸附回收溶液中的Pt(IV)离子。     

Biosorption of cadmium(Ⅱ) from aqueous solutions by industrial fungus Rhizopus cohnii

An important filamentous industrial fungus, Rhizopus cohnii (R. cohnii), was used as an efficient biosorbent for removing cadmium from wastewater. The sorption conditions, such as pH, the dose of biomass and the initial concentration of cadmium were examined. Two kinds of adsorption models were applied to simulate the biosorption data. The uptake of cadmium was higher in weak acid condition than in strong acid condition. Nearly no sorption of cadmium occurred when the pH value was lower than 2.0. Biosorption isothermal data could be well simulated by both Langmuir and Freundlich models. Langmuir simulation of the biosorption showed that the maximum uptake of cadmium was 40.5 mg/g (0.36 mmol/g) in the optimal conditions, which was higher than many other adsorbents, including biosorbents and activated carbon. In addition, the reusability results showed that after five times of sorption and desorption process, the sorption capacity of R. cohnii could still maintain nearly 80%, confirming its practical application in cadmium treatment. Fourier transform infrared spectrum revealed that carboxyl, amino and hydroxyl groups on biosorbent R. cohnii surface were responsible for the biosorption of cadmium.     

Comparative study on biosorption of Pb（ Ⅱ ） and Cr（Ⅵ） by Synechococcus sp.

The comparative study on adsorptions of Pb（ Ⅱ ） and Cr（Ⅵ） ions by free cells and immobilized cells of Synechococcus sp. was performed, in which different aspects including Zeta potential of the cells, the influence of pH, temperature and initial concentration of metal ions, as well as adsorption kinetics and mechanism were referred. The lyophilized free cells have a surface isoelectric point at pH 3, and the correlative experiment indicates that there is an electrostatic adsorption feature of Cr（Ⅵ） and Pb（ Ⅱ ） The immobilization of the free cells by Ca-alginate does not significantly modify the adsorption features of the biosorbent. The absorption processes of Cr（Ⅵ） and Pb（Ⅱ） on both free and immobilized cells are apparently affected by pH and the initial concentration of metal ions in the bulk solution, but are much weakly affected by temperature in the test range of 10-50 ℃. The slow course of biosorption follows the first order kinetic model, the adsorption of Pb（Ⅱ） obeys both Langmuir and Freundlich isotherm models, while the adsorption of Cr（Ⅵ） obeys only Freundlich model. FT-IR results indicate that carboxylic, alcoholic, amide and amino groups are responsible for the binding of the metal ions, and reduction of Cr（Ⅵ） to Cr（Ⅲ） takes place after Cr（Ⅵ） adsorbs electrostatically onto the surface of the biosorbents.     

Kinetic and thermodynamic studies on biosorption of Cu（ Ⅱ ） by chemically modified orange peel

Cu(II) biosorption by orange peel that was chemically modified with sodium hydroxide and calcium chloride was investigated. The effects of temperature, contact time, initial concentration of metal ions and pH on the biosorption of Cu(II) ions were assessed. Thermodynamic parameters including change of free energy), (ΔG^θ), enthalpy (ΔH^θ) and entropy (ΔS^θ) during the biosorption were determined. The results show that the biosorption process of Cu(II) ions by chemically treated orange peel is feasible, spontaneous and exothermic under studied conditions. Equilibrium is well described by Langmuir equation with the maximum biosorption capacity(qm) for Cu(II) as 72.73 mg/g and kinetics is found to fit pseudo-second order type biosorption kinetics. As the temperature increases from 16 °C to 60 °C, copper biosorption decreases. The loaded biosorbent is regenerated using HCl solution for repeatedly use for five times with little loss of biosorption capacity.     

银离子在斛壳丹宁酸树脂表面的吸附和解吸(英文)

将斛壳丹宁酸与甲醛聚合来形成的凝胶作为吸附剂能有效地移去水溶液中的银离子。研究了不同银离子初始浓度、溶液温度、pH值条件下斛壳丹宁酸树脂的附和解吸行为。研究了有关经验动力学模型的适应性。伪二级动力学模型表明银离子的吸附是很快的。用FTIR和SEM对吸附和解吸银离子后的斛壳彤宁酸和斛壳丹宁酸树脂进行表征。银离子在斛壳宁酸树脂上的吸附随着银离子初始浓度的增加而增加,随着溶液温度的升高而减少。在低pH值的H2SO4、HNO3和HCl溶液中进行解吸实验。斛壳丹宁酸树脂在pH2.0~7.0溶液中对银离子表现出高的吸附容量,在银离子初始浓度100.0mg/L、温度296K和pH5.0的条件下达到最大的吸附量97.08mg/g。在1mol/LHCl+1%硫脲溶液中银离子的脱吸率达99.6%。     

微生物固定化吸附剂吸附Pd(II)的研究

微生物法在吸附处理重金属污染和回收贵金属方面具有广阔的发展前景。利用载体A固定化大肠杆菌开发了一种高效微生物固定化吸附剂,研究其对Pd(II)的吸附特性,构建其对Pd(II)的动态吸附模型,并开展了循环再生实验。结果表明,吸附柱的穿透时间和耗竭时间与大肠杆菌的浓度、微生物固定化吸附剂的填充量成正相关,与溶液流速成负相关;载体A:粘结剂:大肠杆菌的质量比为4:1:3,固定化吸附剂添加量为15 g、溶液流速3 mL/min时,吸附柱对Pd(II)有较好的吸附效率,穿透时间和耗竭时间分别为60 min和360 min;使用2 mol/L的HCl对负载Pd(II)后吸附剂进行解吸处理,解吸率达到99.32%;吸附-解吸循环5次后,固定化吸附剂对Pd(II)的吸附量基本保持不变。     

Ge and Cu recovery from precipitating vitriol supernatant in zinc plant

A novel technology using Fe powder as reducing agent for Ge and Cu recovery from precipitating vitriol supernatant in Zn hydrometallurgical plant was investigated. The results show that reaction time, temperature, agitation speed, initial pH value of solution and the amount of reducing Fe have significant effects on recovering Ge and Cu, and the optimum process operating parameters are established as follows: time 120 min, initial pH value 1.5, the dosage of reducing Fe powder 4 g/L, agitation speed 600 r/min and temperature 80 °C. Under these experimental conditions, the recovery ratios of Ge and Cu from precipitating vitriol supernatant in Zn hydrometallurgical plant can reach 96% and 100%, respectively. The content of Ge in the reduced residue reaches up to 2.06% (mass fraction), indicating that the separation and enrichment of Ge from the Zn sulfate solution is realized. The grade of Ge and Cu can reach up to 4.88% and 56.75%, respectively, when the reduced residue is further processed.     

Time focused measurements of roof runoff quality

Runoff properties and their changes during runoff of a 14 year old zinc roof were investigated. Zinc, lead, cadmium, pH value, rain intensity and electric conductivity have been measured for a period of one year. A runoff rate of 3.73 g/m² a and a volume weighted mean zinc concentration of 4.9 mg/L were determined. First flush behaviour was observed in 93% of runoff events. Low rain intensities are correlating with higher zinc concentrations in runoff, whereas the duration of antecedent dry periods could not directly be linked with initial zinc concentrations.     

Tolerance and removal of chromium(Ⅵ) by Bacillus sp. strain YB-1 isolated from electroplating sludge

Four chromium(Ⅵ)-resistant bacteria named YB-1, YB-2, YB-3 and YB-4 were isolated from Cr-electroplating sludge. YB-1 and YB-2 were identified as a member of Bacillus sp. based on morphology and Biolog Microstation System. The strain of YB-1 was selected to test for its resistance and ability to remove Cr(Ⅵ) from aqueous solution. The results indicate that YB-1 exhibits high MIC value which can almost reach 140 mg/L and the growth of YB-1 in liquid medium containing 60 mg/L Cr(Ⅵ) is affected especially in the late exponential phase and stationary phase. Furthermore, the potential of living and freeze-dried YB-1 biomass to remove Cr(Ⅵ) was studied in different pH, biosorbent dose, contact time and initial concentration using the batch method. At the optimal conditions, living and freeze-dried biomass are capable of absorbing 34.5 mg/g and 17.8 mg/g chromium(Ⅵ) at initial concentration of 60 mg/L, respectively. The adsorption data were fitted to Langmuir isotherm model for these two sorbents. Kinetic studies show that the rates of sorption all follow the pseudo-second order kinetics.     

Selective separation of copper and cadmium from zinc solutions by low current density electrolysis

Copper and cadmium ions were selectively separated from zinc sulphate aqueous solution or zinc ammonia/ammonium sulphate aqueous solution by low current density electrolysis.It was shown that the concentration of cadmium ion in zinc sulphate solution decreased from 4.56 g/L to 0.18 g/L in an electrolysis time of 8.5 h,whilst it decreased from 5.16 g/L to lower than 0.005 g/L in zinc ammonia/ammonium sulphate aqueous solution.On the other hand,the deposition rate of copper was so low that it was difficult to...     

Ida~（2-）-H_2O体系浸出低品位氧化锌矿

采用Ida2--H2O体系（亚氨二乙酸盐水溶液）处理高碱性脉石型低品位氧化锌矿,考察浸出时间、液固比、配体总浓度、温度及pH值对矿物中主金属Zn及杂质元素Ca、Mg、Cu、Ni、Fe、Pb、Cd的溶出影响。结果表明：在弱碱性Ida2--H2O体系中,Ca、Mg、Fe不会被大量溶出,有价金属Cu、Ni、Pb、Cd可部分随主金属Zn溶出而进入浸出液;在浸出时间4h、液固比5：1、配体总浓度0.9mol/L、温度70℃、pH8的优化条件下,锌浸出率为76.6%。     

氧化石墨烯-壳聚糖复合物的制备及其吸附性能

采用Hummers法合成的氧化石墨烯(GO)与壳聚糖(CTS)制备复合型吸附剂GO-CTS,通过傅立叶红外光谱仪(FTIR)和扫描电镜(SEM)对结构和形貌进行表征。考察pH、投加量、吸附时间以及铀初始浓度等参数对吸附剂去铀效果的影响。结果表明,对于10mg/L的含铀溶液,GO和GO-CTS的最佳吸附条件分别为:pH=4~7,5;投加量1.0,1.0g/L;吸附时间为1,70min;最大去铀率分别为99.5%,97.5%。GO和GO-CTS的吸附平衡符合Freundlich等温线模型,表明为多分子层吸附,主要以物理吸附为主,最大吸附量分别为78.13和114.94mg/g。     

Tolerance and removal of chromium（Ⅵ） by Bacillus sp. strain YB-1 isolated from electroplating sludge

Four chromium（Ⅵ）-resistant bacteria named YB-1, YB-2, YB-3 and YB-4 were isolated from Cr-electroplating sludge. YB-1 and YB-2 were identified as a member of Bacillus sp. based on morphology and Biolog Microstation System. The strain of YB-1 was selected to test for its resistance and ability to remove Cr（Ⅵ） from aqueous solution. The results indicate that YB-1 exhibits high MIC value which can almost reach 140 mg/L and the growth of YB-1 in liquid medium containing 60 mg/L Cr（Ⅵ） is affected especially in the late exponential phase and stationary phase. Furthermore, the potential of living and freeze-dried YB-1 biomass to remove Cr（Ⅵ） was studied in different pH, biosorbent dose, contact time and initial concentration using the batch method. At the optimal conditions, living and freeze-dried biomass are capable of absorbing 34.5 mg/g and 17.8 mg/g chromium（Ⅵ） at initial concentration of 60 mg/L, respectively. The adsorption data were fitted to Langmuir isotherm model for these two sorbents. Kinetic studies show that the rates of sorption all follow the pseudo-second order kinetics.