络合-超滤-电解集成过程处理重金属工业废水 Ⅰ络合-超滤耦合过程

以废水回用为目的 ,研究了络合 -超滤耦合过程处理重金属工业废水。利用聚丙烯酸( PAA)为络合剂和含 Zn2 + 和 Cu2 + 的重金属废水 ,讨论了各种因素 (如操作压力 (Δp)、膜面流速( VL)、重金属浓度与络合剂添加浓度比 ( L)、p H、体积浓缩因子 ( VCF) )对超滤过程的影响。在 Na Cl或 Na SO4存在的条件下 ,对 Zn2 + 和 Cu2 + 仍可达到 1 0 0 %的去除。在较高的离子强度下 ,如离子强度为 0 .2 0 3mol/L时 ,对 Zn2 +和 Cu2 +的截留率仍可达到 95 %以上。经过浓缩的重金属废水 ,可回收重金属 ,而透过液可以达到回用水的标准     

聚合物强化超滤过程处理含Hg~(2+)废水

研究聚丙烯酸钠(PAASS)与Hg2+络合反应动力学,当PAASS大量过剩及pH值恒为5时,络合反应达到平衡时间为25 m in,反应行为可用拟一级速率方程描述。测定PAASS对Hg2+络合能力,pH=5时每mg PAASS络合容量为1.0 mg。考察pH值、盐浓度和竞争络合剂对Hg2+截留系数的影响,可得:pH=5及负载比LR=1时适宜截留Hg2+;当C l-和SO42-浓度增大时,Hg2+截留系数逐渐降低;酒石酸钠和三乙醇胺不干扰PAASS与Hg2+的络合。进一步研究超滤浓缩行为,结果表明:当pH=5,PAASS及Hg2+初始质量浓度均为100 mg/L时,原料液浓缩15倍,膜通量仅衰减15.0%,浓缩液及渗透液汞质量浓度分别为1499.6,0.03 mg/L。     

络合-超滤技术处理含铜废水

络合剂为聚丙烯酸钠,超滤膜采用芳香聚酰胺膜,研究了络合.超滤处理含铜废水的工艺条件.研究了不同溶液pH值条件下聚合物/盒属离子质量比(P/M)、溶液PH、操作压力、运行时间等操作参数对铜离子去除率和膜通量的影响.结果表明,在一定pH条件下,Cu~(2+)的截留率随P/M的增加而增加;在一定P/M下,适当提高溶液pH值有利于Cu~(2+)的截留.在溶液pH=6、P/M=22条件下,Cu~(2+)的截留率达到97%以上.     

络合-超滤技术深度处理矿山重金属废水

采用壳聚糖络合-超滤技术深度处理有色金属矿山重金属废水,考察了pH值、壳聚糖/铅离子质量比(P/M)、离子强度、运行时间等因素对Pb2+、Cd2+截留率和膜通量的影响。结果表明,在原水Pb2+、Cd2+的质量浓度分别为1.0、0.1 mg/L,pH值为7,P/M值为6的条件下,Pb2+和Cd2+的截留率分别达到96.62%和96.26%,出水满足GB 3838—2002《地表水环境质量标准》中Ⅲ类标准的要求。NaCl浓度的增大使重金属离子的截留率有所降低;随着运行时间的延长,膜通量逐渐减小最后趋于稳定,而运行时间对Pb2+、Cd2+的截留率影响不大。     

PEI络合-超滤耦合过程分离铜和锌废水的研究

水溶性聚合物络合-超滤耦合过程是一种新型、环保处理工业废水的方法。它不但能够实现废水回用和重金属浓缩,而且能有效地分离二元重金属混合液。选取高效、环保的络合水处理剂聚乙烯亚胺(PEI),对含铜、锌的二元重金属废水进行络合-超滤耦合过程研究,探讨了pH值、装载量比L、离子强度等对超滤过程的影响;pH=7时,PEI对Zn2 和Cu2 的络合容量分别为KCu=0.10mgCu2 /mgPEI,KZn=0.06mgZn2 /mg PEI。随PEI浓度增加,超滤膜通量J=35～45L/(m2·h)。     

络合-超滤-纳滤耦合工艺处理铜电镀工业废水

以废水处理和金属回用为目的,研究了络合-超滤-解络-纳滤耦合过程处理铜电镀工业废水.利用聚丙烯酸钠(PAAN)为络合剂处理含Cu2 的电镀废水,讨论了pH、体积浓缩因子等对超滤过程的影响,以及解络、纳滤过程和络合剂再生回用性能.试验研究表明,在络合过程对Cu2 可达到98%的去除,在解络过程对Cu2 的回收率仍可达到96%以上.经过纳滤浓缩的铜电镀废水,可回收铜金属,而滤过液可达到回用水的标准.     

络合-超滤过程处理重金属工业废水

以废水回用为目的,研究了络合 超滤耦合过程处理重金属工业废水。利用聚丙烯酸(PAA)为络合剂和含Zn2+和Cu2+的重金属废水,讨论了各种因素,如操作压力、膜面流速、重金属与络合添加剂的质量比、pH、体积浓缩因子对超滤过程的影响。在NaCl或Na2SO4存在的条件下,对Zn2+和Cu2+仍可达到100%的去除。在较高的离子强度下,如0.203mol/L时,对Zn2+和Cu2+的截留率仍可达到95%以上。经过浓缩的重金属废水,可回收重金属,而透过液可达到回用水的标准。     

聚丙烯酸钠络合-超滤分离钯(Ⅱ)

以聚丙烯酸钠(PAAS)为络合剂,研究钯(Ⅱ)的络合-超滤行为.考察聚合物/金属质量比(rp/m)、pH、膜两侧压差(△p)对膜通量(J)和钯截留系数(RPd)的影响,发现J不随rp/m变化,随pH增大而增大,随△p增大呈线性递增:RPd随rp/m或pH增大而增大,与△p无关.控制rp/m=2和pH=6,PAAS-钯(...     

络合萃取法处理含酚废水技术

本文介绍了络合萃取法处理含酚废水的研究工作。实验研究及工业实施的结果表明,所建立的工业含酚废水络合萃取工艺是可行的、有特色的。采取这一技术,可以通过单一萃取操作使废水含酚量低于国家排放标准,创造直接的社会效益和经济效益。     

纳米SiO2/SDBS复合强化超滤处理含镉废水的影响因素

以纳米SiO2同阴离子表面活性剂十二烷基苯磺酸钠（SDBS）复合的胶束强化超滤处理含镉废水。考察了粉体加入、pH值、粉体浓度对超滤的影响。结果表明,纳米SiO2加入后,膜通量提高了25%,Cd2+截留率有所提高,渗透液中SDBS的浓度在一定条件下有所降低。膜通量、SDBS及Cd2+的截留率随pH值的变化而变化,三者随纳米SiO2加入量的增大而降低。另外,膜阻力主要为膜面吸附和膜孔堵塞阻力。     

Removal of Cadmium Ions from Aqueous Samples by Synechocystis sp.

Abstract

The biosorption of cadmium ions from aqueous solution by dried, immobilized dried and immobilized live Synechocystis sp. was investigated. Sorption of plain Ca-alginate beads, which were used as substrate for immobilization, was also studied for comparison. Removal efficiency of biosorbents was studied as a function of pH (2-8 Volesky , B. ( 1990 ) Biosorption of Heavy Metals ; CRC Press : Boca Raton , FL . Wase , J. , Forster , C.F. (1997) Biosorbents for Metal Ions ; Taylor & Francis : London. Malkoç , E. ; Nuho?lu , Y. ( 2005 ) Investigations of nickel (II) removal from aqueous solutions using tea factory waste . J. Hazard. Mater. , 127 : 120 – 128 . Lodeiro , P. ; Cordero , B. ; Barriada , J.L. ; Herrero , R. ; Sastre de Vicente , M.E. ( 2005 ) Biosorption of cadmium by biomass of brown marine macroalgae . Bioresource Technol. , 96 : 1796 – 1803 . Shen , J. ; Duvnjak , Z. ( 2005 ) Adsorption isotherms for cupric and cadmium ions on corncob particles . Sep. Sci. Technol. , 40 : 1461 – 1481 . Kat?rc?o?lu , H. ; Asl?m , B. ; Türker , A.R. ; At?c? , T. ; Beyatl? , Y. ( 2008 ) Removal of cadmium(II) ion from aqueous system by dry biomass, immobilized live and heat-dried Oscillatoria sp. H1 isolated from freshwater (Mogan Lake) . Bioresource Technol. , 99 ( 10 ): 4185 – 4191 . Pavasant , P. ; Apiratikul , R. ; Sungkhum , V. ; Suthiparinyanont , P. ; Wattanachira , S. ; Marhaba , T.F. ( 2006 ) Biosorption of Cu²⁺, Cd²⁺, Pb²⁺, and Zn²⁺ using dried marine green macroalga Caulerpa lentillifera. Bioresource Technol. , 97 : 2321 – 2329 . ), temperature (20–40°C), initial cadmium ion concentration (50–300 mg/L), and contact time (0–120 min). The maximum biosorption capacities of the dried, immobilized dried, and immobilized live Synechocystis sp. and plain Ca-alginate beads were found as 75.7, 4.9, 4.3, and 3.9 mg/g, respectively at optimum conditions. Biosorption equilibrium was established in about 15 min. Dried biomass of Synechocystis sp. was found to be more suitable and an efficient biosorbent for the removal of cadmium ion from aqueous solution. Both of the isotherm models (Langmuir and Freundlich) were suitable for describing the biosorption of cadmium by the dried biomass of Synechocystis sp. All the tested cyanobacterial forms could be recovered more than 90% and reused in five biosorption–desorption cycles without any considerable loss in the biosorption capacity.     

Removal of Cadmium(II) Ions from Chloride Solutions by Cyanex 301 and Cyanex 302

The main goal of this work was to study and compare the extraction of cadmium(II) ions by the two organophosphorous extractants: Cyanex 301 and Cyanex 302. The effect of different variables influencing the extraction of cadmium(II) ions such as the concentration of acid or metal ion and type of extractant has been investigated. Obtained results from the extraction process were compared with the FT-IR spectra. Results of spectrophotometric analysis confirm the observations of the extraction process, for example, the negative effect of hydrochloric acid on cadmium extraction by Cyanex 302.     

Technology for the Purification of Electroplating Washwater from Cadmium Ions by Membrane and Membraneless Electrolysis

Theoretical Foundations of Chemical Engineering - A technology for removing toxic Cd2+ from electroplating process electrolytes and washwater containing $${text{SO}}_{4}^{{2 - }}$$ or Cl– is...     

Simultaneous Removal of Nickel(II) and Chromium(VI) from Aqueous Solutions and Simulated Wastewaters by Foam Separation

The present investigation was carried out to study the feasibility of foam separation for simultaneous removal of two types of inorganic hazardous contaminants, nickel(II) cations and chromium(VI) anions, from aqueous solutions and simulated wastewaters. The effects of pH of the solution, Ni/Cr ratio, collector and frother concentrations, induction and flotation time, and solution ionic strength on the co-removal efficiency of nickel(II) and chromium(VI) were studied. At the optimum conditions, removals more than 99.5% were obtained for nickel(II) and chromium(VI). The concerned contaminants were effectively removed when they coexisted at low as well as at high concentrations. Coflotation of nickel(II) and chromium(VI) from tap water and simulated electroplating wastewater resulted in removal percentages higher than 99.5% with residual concentrations below their permissible limits in potable water. High removal percentages, DFs, ERs, and VRs were achieved for their radionuclides, ⁶³Ni(II) and ⁵¹Cr(VI), from simulated radioactive process wastewater. The results obtained in this study suggest the feasibility of the developed foam separation process for treatment, in a single-step, of wastewaters contaminated with cationic and anionic inorganic pollutants.     

Preparation of Pectin-Based Biosorbents for Cadmium and Lead Ions Removal

The optimal formation conditions of pectin-based, as well as new hybrid pectin-guar gum, biosorbents were found. The lead affinity for obtained biosorbents was very strong even in solution of pH = 1, in opposite to cadmium, which was adsorbed from solutions of pH ≥ 2. The sorption capacities in the studied conditions were about 0.6 and 0.8 mmol/g for cadmium and lead, respectively. The cadmium removal could be fast and it is almost quantitatively desorbed using 0.25 M HNO₃, while desorption of lead required 1 M HNO₃ to achieve a removal efficiency of ca. 75% from pectin-based beads. The possibility of biosorbents’ reuse was also proved. Addition of guar gum to pectin biosorbent did not change its sorption properties significantly.     

纳米伊/蒙黏土吸附脱除水中Cu~(2+)和Cd~(2+)离子

探索经精细加工的纳米伊/蒙混层黏土吸附水中2种二价重金属离子(即Cu~(2+)和Cd~(2+))的吸附性能,并考察了该黏土在吸附过程中pH值、黏土用量、吸附时间、吸附温度和重金属离子浓度诸因素对水中Cu~(2+)和Cd~(2+)离子吸附性能的影响。结果表明:纳米伊/蒙黏土对水中重金属离子的吸附量随pH值的增加而增加,当pH4时,吸附量基本趋于稳定;在优化条件下,纳米伊/蒙黏土对水中Cu~(2+)和Cd~(2+)的最大吸附脱除率分别为95.15%和91.53%。用准一级和准二级动力学模型拟合纳米伊/蒙黏土吸附Cu2+和Cd2+的吸附动力学过程。结果表明,准二级动力学模型能够拟合纳米伊/蒙黏土对Cu~(2+)和Cd~(2+)的吸附过程。吸附热力学研究还表明,纳米伊/蒙黏土吸附Cu~(2+)和Cd~(2+)属于物理吸附过程。另外,利用Langmuir和Freundlich等温线模型分析纳米伊/蒙黏土分别吸附不同浓度Cu~(2+)和Cd~(2+)的吸附过程。Langmuir模型能有效地拟合纳米伊/蒙黏土吸附Cu~(2+)和Cd~(2+)的等温吸附过程,由其获得的单层纳米伊/蒙黏土对Cu~(2+)和Cd~(2+)饱和吸附量分别为7.99 mg/g和12.68 mg/g。     

用海藻类生物吸附剂去除废水中的重金属离子——一种经济型新技术

Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.     

Removal of Anionic Metal Ions from Wastewater by Hydroxide-type Adsorbents

Generally speaking, anionic metal concentrations in wastewater from industries and mineral processing plants are well above the allowed limits for effluent set by the Ministry of Environment of Japan. Nowadays, the removal of anionic ions has been considered difficult and development of new process is desperately needed. In this paper, we report the development of three hydroxide-type adsorbents, illustrating their adsorption efficiency in removing As, Se, Mo and Sb ions from aqueous solutions. The main finding of this work was that the adsorption behavior was influenced very much by both the pH and the adsorbent concentration. Nevertheless, the newly developed hydroxide-type adsorbents were very effective in reducing the concentration of those anionic ions.     

Removal of Metal Ions from Liquid Solutions by Crossflow Microfiltration

Abstract

The applicability of crossflow microfiltration (CFMF) to the removal of metal ions from liquid solutions was studied. Three treatment processes were employed in this study. The first process was filtration of liquid solutions containing metal ions by CFMF. The second process was CFMF with membranes precoated by CaCO₃ cake. The third process used suspension flocculation as a pretreatment step before CFMF. It was found that CFMF or CFMF with precoated membranes could not remove the metal ions (Cu²⁺, Mn²⁺ and Fe²⁺) from water efficiently. On the contrary, CFMF with suspension flocculation as a pretreatment could remove the metal ions from water completely under suitable pH values. The unsteady-state permeate flux for CFMF with suspension flocculation increased with an increase in temperature but decreased with an increase in pH of the liquid solutions. In addition, an optimal permeate flux existed in the relationship among the permeate flux, crossflow velocity, membrane pore size, and pressure drop. Furthermore, the unsteady-state permeate flux obtained experimentally for CFMF with suspension flocculation could be predicted by a mathematical model developed previously if an equivalent diameter of the flocs in the suspension was used in the model.     

Removal of Arsenic from Wastewaters by Airlift Electrocoagulation. Part 2: Continuous Reactor Experiments

Abstract

Arsenic removal from wastewater is a key problem for copper smelters. Conventional methods either prove to be complicated, expensive, or not sufficiently effective. This work shows the results of electrocoagulation (EC) in aqueous solutions containing arsenic in a newly designed and constructed cylindrical continuous airlift reactor. The residence time distribution measurements showed that the reactor behaved as an ideal continuous stirred tank reactor (CSTR) with perfect mixing. Ten EC experiments were carried out in the continuous airlift reactor with sacrificial iron electrodes. The variables were: initial As(V) concentration, liquid flow rate, and electric current density. The results showed that the airlift EC process could reduce an initial As concentration from 1000 mg L^?1 to 220 mg L^?1 – corresponding to a reduction of 78%. In addition, a 100 mg L^?1 solution was reduced by 88%. The Fe-to-As (mol/mol) ratio, when EC was working properly, was in the range of 1.3–1.5, which is very promising for the future development of the reactor. The arsenic removal is proportional with the electric current, the electric charge and the CSTR residence time. On the other hand, when the flow rate is increased, the arsenic removal decreases.