酸雨对Cu在长三角地区4种典型土壤中的解吸影响

主要研究在不同环境条件下,长江三角洲地区不同母质发育土壤中铜解吸规律.试验采用具有代表性的长江三角洲地区4种母质发育而成的土壤,加入外源铜培育污染土样,以不同pH酸雨为解吸液对污染土样进行解吸.结果表明：随着酸雨的加入,已污染土壤中Cu的解吸量增加;在酸雨pH相同时,酸雨对Cu的解吸量与污染土样中Cu含量呈正变关系;在已污染土壤中Cu含量相同时,Cu的解吸量随着酸雨pH的下降而增加.比较不同母质发育而成的土壤,在pH=3.0、4.0、5.6时,已污染土壤中Cu的解吸量由强到弱的顺序为：沟沟堆积母质、湖相沉积物母质、河相沉积物母质,海相沉积物母质.在pH=2.0时,河相沉积物母质、海相沉积物母质Cu的解吸量增加迅速.     

黑土对百菌清的吸附及解吸行为

[方法]采用平衡吸附法,对黑土吸附百菌清及解吸行为进行研究,了解百菌清在土壤环境中的存在状况及迁移规律。[结果]土壤对百菌清的吸附和解吸经历了快速、减速和平衡3个阶段,土壤对百菌清吸附解吸平衡基本在12 h内完成。黑土对百菌清的吸附符合Henry等温式,在试验质量浓度范围内黑土对百菌清的最大吸附量为1 386.75 mg/kg,最大解吸率为7.93%;pH值对黑土吸附百菌清的影响呈现出正相关性,随pH值增加百菌清吸附量增大,而对百菌清解吸的影响呈现负相关性,随pH值增加百菌清的解吸量减小。[结论]研究表明:土壤pH值对百菌清在土壤中的环境行为具有一定的影响;土壤对百菌清的吸附量与解吸率的相差较大。     

土壤有机质、pH值和表面活性剂对杀菌剂戊菌唑在土壤中吸附与解吸行为的影响

[目的]系统研究土壤有机质、土壤溶液pH值和表面活性剂对土壤中戊菌唑吸附与解吸的影响。[方法]通过标准批量平衡法试验,并采用Freundlich方程对吸附与解吸等温线进行拟合。[结果]有机质含量与戊菌唑在土壤上的吸附量呈正相关;土壤溶液pH值接近戊菌唑的p Ka(1.5)时,吸附量最大;Triton X-114浓度大于CMC时,显著抑制戊菌唑在土壤中的吸附,Triton X-114浓度小于CMC时,无显著影响。[结论]土壤有机质、土壤溶液pH值和表面活性剂对戊菌唑在土壤中吸附与解吸均有显著影响,且土壤有机质是主导因素。     

松果对废水中Cu~(2+)、Pb~(2+)、Zn~(2+)的吸附特性研究

以松果作为吸附剂进行了去除废水中Cu2+、Pb2+、Zn2+的吸附及解吸试验,研究了溶液pH值、吸附剂投加量、反应时间、溶液初始浓度对吸附效果的影响,以及不同pH值对达到吸附平衡的松果的解吸影响。结果表明:当pH值为5.0～5.5,Cu2+、Pb2+、Zn2+初始质量浓度约为25 mg/L时,吸附剂的最佳投加量分别为3、1.5、3 g/L,去除率分别为55.32%、86%、39.96%。3种重金属离子的吸附动力学方程符合Lagergren准二级动力学方程,R2均大于0.998。等温吸附研究表明:Freundlich方程能较好地描述Cu2+的等温吸附过程,Langmuir方程则能更好地描述Pb2+和Zn2+的吸附过程,用Langmuir方程拟合等温吸附数据得出松果对Cu2+、Pb2+、Zn2+的最大吸附量分别为9.10、31.65和9.60 mg/g。强酸是一种理想的Cu2+和Zn2+解吸剂。     

胞外聚合物对水中Cu~(2+)的吸附研究

以胞外聚合物作为生物吸附剂,对水中微量Cu2+的生物吸附特性进行研究,分析了原始pH值、胞外聚合物投加量、吸附时间对Cu2+吸附去除率的影响。研究结果表明:当初始Cu2+的质量浓度为10mg/L时,吸附最佳原始pH值范围为2～5,胞外聚合物的投加量为16mg/g,吸附时间为40min。Cu2+的吸附过程可分为3个阶段:①8min的快速吸附阶段;②8～40min达表观一级动力学吸附阶段;③吸附-解吸平衡阶段。Cu2+吸附等温线与Freundilich方程拟合良好。     

文物埋藏土壤中Cu、Fe的吸附解吸特征研究

为分析文物埋藏土壤中Cu、Fe的吸附解吸特征,进行了Cu、Fe的等温吸附/解吸实验。结果表明,供试土样吸附Cu和Fe是一个自发、吸热、熵增的反应,解吸过程存在滞后现象。土样对铁的吸附能力比铜强,但铜的解吸能力比铁强。本研究揭示了文物埋藏土壤中Cu和Fe的迁移规律,对埋藏土壤中文物腐蚀机理研究具有重要的参考意义。     

Cu_2O光催化降解水中环境内分泌干扰物己烯雌酚性能的研究

采用水解法制备Cu2O,以Cu2O为催化剂,对光催化降解环境内分泌干扰物己烯雌酚(DES)的性能和影响因素进行了研究,利用高效液相色谱法(HPLC)测定降解后水中DES的含量.探讨了溶液的初始浓度、催化剂投加量、pH值以及光照时间对降解效率的影响.当DES初始浓度为51μg/mL,催化剂投加量为0.8g/L,pH值=4.0,光照120min的条件下降解效果达95.02%.     

文物埋藏土壤中Cu、Fe的吸附解吸特征研究

为分析文物埋藏土壤中Cu、Fe的吸附解吸特征,进行了Cu、Fe的等温吸附/解吸实验。结果表明,供试土样吸附Cu和Fe是一个自发、吸热、熵增的反应,解吸过程存在滞后现象。土样对铁的吸附能力比铜强,但铜的解吸能力比铁强。本研究揭示了文物埋藏土壤中Cu和Fe的迁移规律,对埋藏土壤中文物腐蚀机理研究具有重要的参考意义。     

纳污水体沿线土壤中重金属含量分析

以HNO3-HF-HClO4消解土壤样品,用原子吸收光谱法对山东某纳污水体沿线的土壤样品中重金属Pb、Cr、Zn、Cu、Cd、Ni的含量进行了分析测定.测定结果表明,纳污水体沿线土壤pH值范围为6.97～10.1,重金属含量在此pH值范围内均低于<土壤环境质量标准>(GB 15618-1995)中三级评价标准,说明该纳污水体对其沿线土壤重金属含量影响较小.     

海藻酸钙包埋枝孢霉对水中Cu~(2+)吸附性能研究

利用海藻酸钙包埋枝孢霉对水中Cu2+吸附性能进行研究。实验结果表明:当海藻酸钙质量分数为3%,CaC l2质量分数为4%,菌体积分数为15%时,包埋制得的固定化小球具有较好的机械性能和较高的吸附量,生物吸附平衡时间3 h。固定化空白小球和活菌的最佳pH值分别为3.5和4.0。在质量浓度为30—500 mg/L时,吸附过程较好地符合Langmu ir吸附模型。在浓度为0.1 mol/L的多种解吸剂中,HNO3解吸效果最好,解吸率达到93.84%。包埋小球重复利用3次,吸附性能没有明显变化。     

MICROWAVE-ASSISTED EXTRACTION OF GLYCYRRHIZIC ACID FROM LICORICE ROOT-EFFECT OF THE PROPERTY OF SOLUTION ON EXTRACTION OF GA

The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concentration of ethanol, ammonia and cation (M+), pH of extraction solution, different kinds of organic solvent etc. The results show that 50%-60%(v/v) ethanol can reach high percentage extraction of GA. If 1% (v/v) ammonia solution was added into 60%(v/v) ethanol, the percentage extraction can be increased from 2.0% to 2.31%. Without ammonia, 50mmol/L [M+] (M+ = K+, NH4+) was added into 60%(v/v) ethanol, percentage extraction of GA can reach about 2.26%. If pH of solution (60% ethanol) was adjust to pH=4.0, it can reach high percentage extraction. If pH of solution (60% ethanol + 50mmol [M+], pH=6.1) was adjust tO PH=4.0, especially M+ is K+ or NH4+, it can reach almost same extraction efficiency as that of 1% ammonia solution + 60% ethanol, and the operation environment can be greatly improved.     

Use of three types of magnetic biochar in the removal of copper(II) ions from wastewaters

Three types of magnetic biochars (MBC1, MBC2, and MBC3) were synthesized from biochar using NaBH₄ as a reducing agent of Fe(II) to Fe(0) to remove copper(II) ions from different wastewaters. Based on the research it was found that removal of copper(II) ions by MBC1 occurs with a yield of 99.8% for the concentration 50 mg/dm³ and decreases to 71.7% at 200 mg/dm³. The maximum pH sorption was found at pH 5. The highest correlation coefficient values (65.55 mg/g) were obtained for the Langmuir isotherm model. Application of 0.5 mol/dm³ HNO₃ as a desorbing agent gives the highest desorption percentage 98.92%.     

Recovery of cellulases by adsorption/desorption using cation exchange resins

Cellulases from Trichoderma reesei were recovered by adsorption in sodium acetate buffer at lower pH using cation exchange resins followed by desorption at higher pH. The weakly acidic ion exchange resin WK10 was found to be the best among the six resins tested in terms of the enzyme activity recovery. The optimal pH values for the adsorption and desorption were 4.0 and 8.0, respectively, and the optimal adsorption and desorption times were both 5 h. Almost 100% of the initial cellulase activity was recovered under the optimal conditions with the supplement of β-glucosidase, which was unable to be efficiently recovered due to its strong adsorption (95.7%) but poor desorption (1.9%).     

Adsorption and desorption of copper(II) from solutions on new spherical cellulose adsorbent

An investigation was conducted on the adsorption and desorption of copper(II) from aqueous solutions with a new spherical cellulose adsorbent containing the carboxyl anionic group. Various factors affecting the adsorption were optimized. The adsorption of Cu²⁺ ions on the adsorbent was found to be dependent on the initial time and pH, the concentration, and the temperature. The adsorption process follows both Freundlich and Langmuir adsorption isotherms and was found to be endothermic (ΔH = 23.99 kJ/mol). The Cu²⁺ ions adsorbed on the adsorbent can be recovered with a NaOH or HCl aqueous solution. The maximum percentage of recovery is about 100% when 2.4 mol/L HCl solution is used. In addition, only 7.2% of the adsorption capacity is lost after 30 replications of the adsorption and desorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 478–485, 2002; DOI 10.1002/app.10114     

Investigation of ultrasound assisted regeneration of Ni–bentonite with response surface methodology (RSM)

This paper assesses the potential of ultrasonic desorption of toxic heavy metal Ni(II) from bentonite for regeneration purposes. Response surface methodology (RSM) was employed to optimize the desorption of Ni(II) retained on bentonite by varying the amount of adsorbent, contact time, pH and ultrasound time. The results indicated that in the present experimental setup, the pH and the ultrasound time were the most significant variables affecting Ni(II) desorption from bentonite. Based on statistical analysis, the Ni(II) desorption model was highly significant with very low p-values (< 0.0001) and the optimal control parameters were determined as follows: solid/liquid ratio (0.5 g/mL), contact time (6 h), pH (3.37) and ultrasound time (30 min). The experimental value of desorption percentage (59.4%) for regeneration of bentonite under the optimum conditions is in agreement with the predicted value of 64.5%.     

线路板微蚀刻废液的综合利用方法研究

文章对线路板厂微蚀刻废液资源化综合利用进行了研究。实验结果表明,通过加入液碱,控制pH在3.5~4.0范围内,可先基本除去微蚀刻废液中的有机物。经过除杂后的滤液,通过沉铜、氧化铜制备工序,最后制得的氧化铜干基含铜量可达78.8%。     

Desorption Behaviour of Regular Adsorbed Polyampholytic Layers

The desorption behaviour of the diblock polyampholyte PMAA-b-PDMAEMA, poly(methacrylic acid)-block-poly((dimethylamino)ethyl methacrylate), preadsorbed on silicon substrates was investigated under the influence of several desorption agents. The investigated polyampholyte is known to adsorb in regular structures directly from aqueous solutions onto silicon substrates. While the adsorption process is mainly determined by electrostatic interactions, two kinds of desorption mechanism should be assumed. The first mechanism is based on changed electrostatic conditions caused for instance by a strong change in pH of the aqueous solution. The other mechanism is observed after treatment with hydrophobic organic solvent, which leads to the desorption of hydrophobic adsorbed polyampholyte chains, while the electrostatically attached ones will not be influenced. To complete the desorption experiments with organic solvents also adsorption experiments from analogous polyampholytic solutions in the same organic solvents were performed. The amount of polymer at the substrate surface after adsorption or desorption experiments was determined using ellipsometry. Atomic force microscopy (AFM) was used to investigate the surface topography of dried samples after the desorption process.     

The Adsorption and Desorption Characteristics of EDTA-Chelated Copper Ion by Activated Carbon

Abstract

This paper addresses the effect of EDTA, a strong agent, on the removal of copper ion from solutions using activated carbon adsorption. Experimental studies indicate the presence of EDTA significantly altered the adsorption behavior of copper on the activated carbon due to the formation of copper chelate species in the solution. The adsorption isotherms and kinetics were found to be strong functions of solution pH and the ratio of copper ion and EDTA concentrations. Adsorption of EDTA-Cu chelates was found to be more favorable than those of free copper ion and unbound EDTA species in the solution. Experimental results indicated that the desorption of chelated copper ion from activated carbon by NaOH and HClO⁴ solutions was influenced by the initial adsorption conditions. A significantly higher quantity of copper ion was recovered with HClO⁴ than with NaOH. Combining the adsorption and desorption data of copper and EDTA, and an understanding of the species distribution of copper in the presence of EDTA, the behavior of the adsorption of EDTA-chelated copper on the activated carbon was described. The predominant adsorbed copper species was the chelated form, CuEDTA^2-, which can be adsorbed on activated carbon surfaces with either the Cu end or the EDTA end bonding directly to the surface.     

大孔树脂纯化废次烟叶中烟草多酚的工艺

通过吸附和解吸附实验,从6种大孔树脂中筛选出适于分离纯化废次烟叶中烟草多酚的大孔树脂,并确定该大孔树脂纯化工艺参数。结果显示,D101大孔树脂能够较好的富集纯化废次烟叶中的烟草多酚,当提取液浓度为2.5 mg/mL,pH值为4.0,上样液流速为2.0 mL/min,洗脱液为80%乙醇溶液,洗脱液流速为2.0 mL/min时,纯化效果最好,烟草多酚的动态回收率为70.37%。     

Fluridone adsorption–desorption on organo-clays

The adsorption–desorption of the herbicide fluridone on Na-montmorillonite and several organo-montmorillonite complexes was studied at a variety of loadings of the organic cation and pH levels. The aim was to find the organo-clay complex, which would be an optimal adsorbent for the hydrophobic fluridone. The organic cations studied were hexadecyltrimethylammonium (HDTMA), benzyltriethylammonium (BTEA), benzyltrimethylammonium (BTMA) and methylene blue (MB) at loadings equal to 25%, 50% and 100% of the cation exchange capacity (CEC) of the clay-mineral. The adsorbed amount of fluridone increased several-fold when montmorillonite was preadsorbed by the organic cation HDTMA up to its CEC and with BTMA at a loading of 5/8 of the CEC. BTEA and MB did not improve the adsorption capacity of the clay for fluridone. The results suggest that interactions between the phenyl rings of the herbicide and that of a small organic cation are geometrically easier to establish than with a larger organic cation. A reduced interaction between the phenyl rings of MB and those of fluridone may account for the low affinity of fluridone adsorption on montmorillonite-MB. In all cases, fluridone adsorption increased with decreasing pH and reached 100% for pH 2.7. Protonation of fluridone molecules with decreasing pH would result in increased adsorption through cation exchange. Thus, by regulating the pH, complete fluridone adsorption can be achieved. Desorption isotherms demonstrate high degree of irreversibility of the adsorption–desorption process and suggest that strong binding mechanisms dominate the fluridone-clay and organo-clay interactions. The results for fluridone adsorption–desorption demonstrate that, for similar molecules, a clay-based slow release formulation can be designed by first lowering the pH.