聚电解质强化超滤技术处理钨(Ⅵ)

以聚季铵盐-6(PQ6)强化超滤技术处理钨(Ⅵ),考察了渗滤对PQ6预处理的影响.结果表明,随渗滤体积增加PQ6截留系数逐渐增大到1,PQ6损失率为12.7%,膜通量(J)轻微增大.研究了pQ6与金属质量比r和pH值对钨截留系数(Rw)和J的影响,当r从1增大到3,Rw线性递增,此后趋于1,PQ6对钨(Ⅵ)的络合容量[PQ6/钨(Ⅵ)]为3.0 mg/mg;当pH值从3增大到9时,Rw基本不变:J随r增大略有下降,但不随pH值变化.在r=3和pH=7的条件下,当体积浓缩因子为16时,J下降15.2%,Rw接近1,截留液钨浓度从20 mg/L增大到317.5 mg/L渗透液钨浓度约为0.04 mg/L,钨(Ⅵ)被有效浓缩.     

聚电解质强化超滤技术处理钨(Ⅵ)

以聚季铵盐-6(PQ6)强化超滤技术处理钨(Ⅵ),考察了渗滤对PQ6预处理的影响.结果表明,随渗滤体积增加PQ6截留系数逐渐增大到1,PQ6损失率为12.7%,膜通量(J)轻微增大.研究了pQ6与金属质量比r和pH值对钨截留系数(Rw)和J的影响,当r从1增大到3,Rw线性递增,此后趋于1,PQ6对钨(Ⅵ)的络合容量[...     

陶瓷膜微滤-聚合物强化超滤处理高浓度含镍废水

实验研究了0.5 mm孔径陶瓷膜对高浓度含镍废水的微滤行为,以聚丙烯酸钠(PAAS)强化超滤技术深度处理陶瓷膜渗透液,考察了PAAS与金属质量比(rp/m)和pH值对恒容超滤膜通量(J)和镍截留系数(RNi)的影响,研究了超滤浓缩、解络合、洗涤及PAAS循环使用过程. 结果表明,pH=9时,陶瓷膜浓缩时J先快速降低、缓慢下降后再较快降低,RNi接近1,当体积浓缩因子从1增大到10时,截留液镍浓度(Cr)从5562.71 mg/L浓缩至55507.76 mg/L,渗透液镍浓度(Cp)为13.26 mg/L. PAAS强化恒容超滤时,J不随rp/m变化,随pH值增大而增大,RNi随rp/m或pH值增大而增大;超滤浓缩时,控制pH=9和rp/m=9,RNi接近1,Cr呈线性递增,Cp"0.05 mg/L;在pH=3条件下对超滤浓缩液解络合,解离平衡时间为9 min,解络合率为81.9%;以pH=3的盐酸溶液洗涤解络合液,镍洗脱率为98.8%. 再生PAAS络合性能良好,可循环使用.     

聚季铵盐强化超滤分离铼(Ⅶ)

以聚季铵盐-6强化超滤技术分离铼(Ⅶ),考察聚季铵盐与金属质量比w、pH值、外加盐、运行时间和操作压力对铼截留系数R和膜通量J的影响,结果表明:当w从1增大到7时,R迅速递增,w达到7时的R为0.995,继续增大w,R逐渐趋于1;J随w增大略有下降;当pH值从3增大到8时,R和J几乎不随pH值变化而变化;随着外加盐质量浓度递增,R逐渐递减至不变,J略有下降;随着运行时间延长,R基本不变,J轻微衰减;当操作压力增大时,R不变,J呈线性快速递增。研究铼(Ⅶ)-聚季铵盐体系的超滤浓缩行为,控制w=7,pH=7,温度25℃和压力60 kPa,当体积浓缩因子为40时,J仅衰减20.1%,在浓缩过程中R均接近1,截留液铼质量浓度从5 mg/L增大到198.3 mg/L,渗透液铼质量浓度约为0.04 mg/L,铼被有效浓缩。     

L35-硫酸铵双水相体系萃取水溶液中Cr(VI)

以L35-(NH4)2SO4-H2O双水相体系萃取模拟废水中Cr(VI),考察了初始Cr(VI)浓度、水相pH值、胶束电荷调节剂1812用量、萃取时间、相分离时间、L35浓度、(NH4)2SO4浓度及萃取温度对Cr(VI)萃取率的影响. 结果表明,溶液pH值对Cr(VI)萃取率和分配系数影响最大;加入1812后,Cr(VI)萃取率和分配系数明显提高;随温度升高,两者均逐渐降低;随L35和(NH4)2SO4浓度增加,Cr(VI)萃取率逐渐提高并趋于恒定;萃取和相分离时间均较短;在最佳萃取条件下,Cr(VI)单级萃取率达92%(w),分配系数达15以上. 四级错流萃取的理论计算和实验结果基本一致,Cr(VI)浓度由2 g/L降到0.5 mg/L以下,达到国家排放标准. Cr(VI)依靠其相对疏水性以增溶方式及静电引力方式进入L35胶束内部而被萃取. 用NaOH水溶液对萃取相单级反萃取,Cr(VI)反萃率达99.5%(w)以上,浓缩倍数>4.     

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-超滤耦合技术处理Cd^（2＋）模拟废水的研究

研究聚丙烯酸钠PAASS与模拟废水中Cd2 络合反应动力学,结果表明:当pH为6、Cd2 浓度为10 mg·L-1和PAASS浓度为5000 mg·L-1时,络合反应符合拟一级速率方程.考察负载比对Cd2 截留系数R的影响,可得PAASS络合容量为0.033 g Cd·(g PAASS)-1.考察pH和竞争络合剂对R的影响,发现当pH从5增大到6时,R迅速增大;竞争络合剂三乙醇胺或酒石酸钠使R下降.研究络合体系超滤浓缩行为,结果表明体积浓缩因子为10时,膜通量仅下降14.6%,R值大约为1;浓缩液用于解离研究,控制解离pH为2.5,可得:当截留液镉浓度为99.6 mg·L-1时,渗透液镉浓度可达93.1 mg·L-1,对应络合物解离效率为93.5%;解离液用于超滤洗涤,当洗涤液体积为原料液体积4倍时,截留液镉浓度从洗涤前99.6 mg·L-1降低至洗涤结束时3.87 mg·L-1,镉洗脱率为96.1%,洗涤后聚电解质纯度高.     

铝污泥基复合凝胶球对Cr(VI)的吸附性能与机理

以铝污泥、聚乙烯醇、海藻酸钠为原料，采用溶胶-凝胶、冷冻干燥技术制备铝污泥基复合凝胶球 (AS-GEL)，吸附溶液中Cr(VI)。通过静态吸附实验探究pH、AS-GEL投加量、初始质量浓度、温度、吸附时间、共存阴离子浓度对AS-GEL吸附Cr(VI)的影响。采用 SEM、FT-IR、XPS等技术对AS-GEL吸附Cr(VI) 的机理进行分析。结果表明：在pH=4、AS-GEL投加量为1.2 g/L、Cr(VI)初始浓度200 mg/L、温度为35℃、吸附时间为120 min、无其他阴离子共存的条件下，AS-GEL对Cr(VI)的最大吸附量为73.364 mg/g。共存阴离子影响顺序为PO43- >NO3->Cl-。吸附过程符合Langmuir等温吸附模型和准一级、二级动力学方程。其主要吸附机理包括质子化基团对Cr(VI)的静电吸附及还原作用。通过5次吸附-解吸实验，其吸附量保持初次吸附量的89.71%。同时，AS-GEL具有成本低、固液易分离的特性，有望应用在工程上。     

聚硅酸铝铁处理含铬废水的研究

用三氯化铁、三氯化铝及硅酸钠制备了聚硅酸铝铁,并研究了其作为絮凝剂对Cr(VI)的处理效果。结果表明:聚硅酸铝铁对Cr(VI)有很好的去除效果。聚硅酸铝铁的投加量、pH值及搅拌时间对Cr(VI)的吸附有较明显的影响,其中pH值的影响最为显著。由正交试验分析得出的最佳条件为:絮凝剂6g/L,pH值6,搅拌时间40min。此时,Cr(VI)的去除率为99.77%。     

络合超滤-软化水过程的模型分析

采用吸附-两性模型探讨了聚电解质-离子配位体的组成,指出了阴、阳离子因吸附到聚电解质上形成聚电解质-离子配位体,其在膜表面的吸附,导致膜表面的荷电,得出了络合超滤对离子截留的截留机理除了络合效应外,可能还与膜表面的静电相互作用有关。分析了络合超滤软化工艺取代反渗透阻垢工艺的可行性。     

竹炭对溶液中微量铬离子的吸附研究

研究了竹炭粒径、加入量、pH值、吸附时间、Cr(Ⅵ)初始浓度等因素对竹炭吸附Cr(Ⅵ)的影响。实验结果表明,竹炭对水中微量Cr(Ⅵ)离子有较好的吸附性能。当Cr(Ⅵ)离子初始浓度为100μg/mL时,在50 mL Cr(Ⅵ)离子溶液中加入0.3 g60目竹炭,pH为2.0,吸附振荡温度为25℃,吸附3 h,Cr(Ⅵ)离子吸附率达99.5%。竹炭对Cr(Ⅵ)离子的吸附可较好地符合Freundlich等温吸附模型。     

Effect of interlayer anions on chromium removal using Mg–Al layered double hydroxides:Kinetic,equilibrium and thermodynamic studies

The influence of interlayer anions such as NO3-, SO42-and Cl-on Mg–Al hydrotalcites for Cr(VI) removal from aqueous solution was studied. The structure of the prepared LDHs was characterized by XRD, SEM, FTIR, TGA, BET surface area and p Hzpc. The sorbent ability and sorption mechanisms were also investigated. The LDHs exhibit high removal for Cr(VI), and the sorbed amount depends on the nature of interlayer anion, which decreased in the following order: NO3-N Cl-N SO42-. Nitrate-containing LDH reached a Cr(VI) sorption equilibrium within only 30 min. The effects of operating conditions, including initial concentration, solution p H, agitation time and sorbent amount have been studied in batch mode. The optimum conditions were observed at an initial concentration of 100 mg·L-1, p H = 6, agitation time of 60 min and a sorbent dose of 2 g·L-1. The equilibrium data were fitted to the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The Langmuir model was found to sufficiently describe the sorption process, offering a maximum sorption capacity of 71.91 mg·g-1. The sorption kinetic follows pseudo-second-order reaction with high accuracy. Thermodynamic parameters suggested that the sorption process is spontaneous and endothermic in nature.     

聚季铵盐辅助络合-超滤提取钨(Ⅵ)(英文)

Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.     

颗粒活性炭载纳米零价铁去除水中的Cr(Ⅵ)

以Fe2+溶液为原料、NaBH4为还原剂,采用传统液相还原技术合成了颗粒活性炭(GAC)载纳米零价铁(nZVI)复合材料GAC-nZVI,用扫描电镜对GAC-nZVI进行表征,通过间歇实验考察了其对去除Cr(VI)的影响。结果表明,GAC能阻止nZVI颗粒聚集,合成的GAC-nZVI能有效去除水中的Cr(VI)。在Cr(VI)初始浓度50 mg/L、温度40℃和pH=2.0、投加GAC-nZVI 3.0 g/L的条件下反应5 min,Cr(VI)去除率为99.4%。pH=2.0?4.0时,处理后水中总铬浓度均低于1 mg/L,表明残留少量Cr(III)。随pH值和Cr(VI)浓度增加,Cr(VI)去除率降低;随反应温度和GAC-nZVI投加量增加,Cr(VI)去除率增加。准一级动力学模型可用于描述Cr(VI)的去除过程。相同条件下,GAC-nZVI去除Cr(VI)的反应速率常数达0.19797 min?1,为原颗粒活性炭反应速率常数0.0023 min?1的86倍。随pH值降低或反应温度和GAC-nZVI投加量增加,反应速率常数增加。     

聚丙烯酸复合铝改性膨润土制备及其对Cr(VI)的吸附

为改善膨润土对Cr(VI)的吸附性能,用铝、丙烯酸聚合及十六烷基三甲基溴化铵改性合成聚丙烯酸复合铝改性膨润土。采用X射线衍射、红外光谱和扫描电子显微镜对天然膨润土和改性膨润土进行表征。结果表明,在25℃、溶液pH=5~6时,0.5 g吸附剂对200 mL浓度为20 mg/L Cr(VI)的平衡吸附量为1.996 mg/g,平衡吸附时间为130 min,且固液分离容易。吸附过程较好地符合Lagergren二级吸附动力学方程和Freundlich等温吸附方程,颗粒状吸附剂对Cr(VI)的吸附以络合吸附为主。     

Removal of Ag(I) and Cr(VI) by Complexation-Ultrafiltration and Characterization of the Membrane by CFSK Model

Removal of Ag(I) and Cr(VI) by complexation-ultrafiltration, anionic polyacrylamide being the complexation agent, has been reported. Effects of operating variables such as initial metal ions concentration in feed, feed pH, polymer-to-metal ions ratio, and applied pressure on the removal of metal ions were studied at a constant feed flow rate of 15 L/min. Maximum rejection obtained were close to 100% for Ag(I) and 94% for Cr(VI) ions in single ion system; and for binary ions system it is 87% for Ag(I) and 76% for Cr(VI) ions. The membrane was characterized using the combined-film theory-Spiegler-Kedem (CFSK) model.     

光催化法处理含Cr(VI)废水的研究

采用P 25 TiO2作为光催化剂,研究了废水的pH值、Cr(VI)的初始浓度、气氛及有机物等因素对含铬废水中Cr(VI)去解率的影响。结果表明,在pH值为3.0时,光催化反应速率最大;反应气氛对该体系中Cr(VI)的光催化还原无明显影响;苯酚、葡萄糖等有机物的存在能有效地促进Cr(VI)的光催化还原,当加入与Cr(VI)等物质的量的苯酚或葡萄糖时,150 mL反应液[Cr(VI)浓度为0.96 mmol/L],0.15 g光催化剂,经12 W紫外灯照射反应120 m in,Cr(VI)完全被去除,相对于在反应体系中不加有机物时,Cr(VI)光催化还原效率提高了近100%;Cr(VI)的光催化还原符合L-H动力学规律。     

Studies of adsorption behavior of crosslinked chitosan for Cr(VI), Se(VI)

In this work, it was found that crosslinked chitosan (CCTS) had strong adsorption ability for some anions under certain conditions. Cr(VI) and Se(VI) existed in anion forms in aqueous solution, and their adsorption rates by CCTS were 97% for Cr(VI) at pH 3.0 and 95% for Se(VI) at pH 4.0. In addition, the adsorption balance time and isotherm of CCTS for Cr(VI) and Se (VI) were discussed and adsorption mechanism was explained. This research will be useful for designing CCTS‐based adsorption for metallic toxin removal and preconcentrating Cr(VI) and Se(VI) in their trace analysis. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3216–3219, 2000