从含钼废液中萃取回收铼

介绍了从含钼废液中萃取回,收铼的工艺条件。第１步钼铼共同被萃取;第２步只有铼进入伯胺－中性磷酸盐有机相,分离系数βＲｅ／Ｍｏ〉１０＾４,高铼酸钾产品纯度大于９９％。     

活性炭吸附法去除冶炼废水COD的研究

采用活性炭吸附法对株冶冶炼废水进行了COD去除研究,考察了pH值、反应时间、活性炭用量、反应温度对去除率的影响。结果表明：采用粉末活性炭为吸附剂,当pH值为8．5,搅拌时间为0．5h,活性炭用量为0．25g／L,温度为25℃时,COD去除率达到64．87％,出水COD约为20mg／L。     

从废酸中萃取铼的工艺优化

优化萃取-反萃工艺条件回收污酸中铼,选取N235:仲辛醇:煤油=20:20:60作为萃取剂的配比,铼的萃取率为88.42％.负载有机相用氨水反萃时,选取浓度10％～12％氨水反萃时最优.采用污酸预处理-萃取-反萃工艺生产铼酸铵,预处理得到的铼液含Re为1.2g/L,萃前铼液的杂质总量≤0.4 g/L,铼的萃取率为98％...     

D296树脂从含铼酸性溶液中吸附铼的研究

采用离子交换法从含铼酸性溶液中提取铼,通过静态试验确定选用D296树脂,通过动态试验考察了料液pH、流速和料液与树脂体积比对铼吸附率的影响,并测定了铼吸附曲线。结果表明,在反应温度25℃、料液pH=1.5、吸附流速每小时7.2倍树脂床体积的条件下,铼吸附率达到97.91%,每克D296树脂对铼的饱和吸附容量为114mg。     

吸附去除水产养殖中氨氮研究进展

介绍了吸附去除水产养殖中氨氮的重要性和优点,讨论了水的pH值、所含金属离子和有机物对吸附去除氨氮效果的影响,对常用的活性炭吸附剂、树脂吸附剂、沸石吸附剂和其他矿石、废弃物吸附剂的改良研究进行了比较,指出了其存在的一些问题,并对研究方向进行了展望.     

生物吸附法在去除废水中重金属离子的应用研究

生物吸附法用于从废水中去除和回收重金属离子具有其它传统处理方法不可比的优势,有着广泛的发展前景。文章就近年来生物吸附重金属离子的常用生物吸附剂、吸附机理及应用废水处理的研究及应用现状进行了综述。     

铜萃取过程中三相絮凝物的生成与处理

介绍铜萃取过程中三相絮凝物的生成原因及处理方法,列举了五个典型的絮凝物灾难性例子,重点介绍了利用卧式沉降离心机离心法分离絮凝物的试验过程。     

D302-Ⅱ树脂吸附铼的性能研究及应用

针对地浸采铀浸出液低含量铼的回收,研究了D302-Ⅱ弱碱性阴离子交换树脂吸附和解吸铼的性能和机制。通过静态试验考察温度、酸度、时间对树脂吸附的影响;通过动态试验考察了溶液酸度和流速的影响,并进行了解吸剂及其浓度影响试验、抗干扰试验及树脂再生的试验;用地浸采铀浸出液通过D302-Ⅱ树脂,进行模拟回收铼试验。结果表明,D302-Ⅱ树脂对铼的吸附速率快,吸附反应速率常数k=1.6×10-3s-1,半交换期t1/2=433 s。吸附酸度在pH 2.0～5.0范围内,有利于铼的吸附。吸附平衡服从Freundish吸附等温式,吸附反应放热,反应可在常温下进行。动态上柱酸度选择为pH 2.0～5.0,流速1～2 ml.min-1,铼的吸附率可达95%以上;洗脱液选择NH4OH,25倍树脂床体积的3 mol.L-1NH4OH溶液可将铼洗脱完全。地浸采铀浸出液中的共存离子不影响铼的吸附和解吸,0.5 mol.L-1H2SO4溶液可使树脂再生。树脂对铼的静态和动态吸附容量分别为166和162 mg.g-1干树脂,对浓度低至0.03 mg.L-1铼溶液吸附和解吸,回收率可达96%～102%,表明该树脂有较好的应用前景。     

树脂吸附法去除冷轧反渗透浓盐水中COD的研究

冷轧反渗透浓盐水中含有大量难降解有机物,属于高电导率、高COD浓度的特种废水,如将其直接排放会造成严重的环境污染.吸附法可以从稀溶液中有效回收单质、离子或特定化合物.研究采用树脂吸附工艺去除冷轧反渗透浓盐水中的COD.结果表明,树脂吸附法对去除冷轧反渗透浓盐水中的COD有一定的效果,大孔弱酸性丙烯酸系阳离子交换树脂(D113)投加量为3.0 g/L时冷轧反渗透浓盐水中COD去除效果最好,反应进行15min内,有机物浓度迅速下降,去除率在18.9％ ～36.9％之间.     

硅藻土对含钒废液中钒的吸附性能研究

湿法提钒工艺中会产生大量含钒废水,直接排放会造成环境污染和资源浪费。硅藻土具有比表面积大、孔隙多、密度小、吸附性能及渗透性较强等优点,广泛应用在环境治理领域。以硅藻土为吸附剂,采用静态吸附试验研究吸附时间、污染液初始浓度、pH值和硅藻土投入量对钒的吸附效果;对试验数据进行吸附热力学和动力学拟合,探究了吸附机理及特征。研究表明：硅藻土的主要成分是SiO₂,含有少量蒙脱石和绿泥石,硅藻壳体为圆盘状,壳体表面有数量众多的微孔结构。热力学拟合中,硅藻土的吸附过程更符合Freundlich模型,R²为0.901 0,属于多分子层吸附和表面吸附;动力学拟合中,准二级动力学模型的相关系数比准一级动力学模型高,R²为0.995 4,说明吸附过程以化学吸附为主导。当吸附时间24 h,钒污染液初始浓度1 mg/L,污染液用量50 mL,pH值5,硅藻土投加量2 g时,去除率最优,达到98.21%。硅藻土对污染液中钒的吸附效果较好,可作为吸附剂治理钒污染。     

浅析铜冶炼企业废水COD去除工艺

针对板框式压滤机固液分离容易出现有害气体逸散,造成低空污染的问题,开展了技术研讨,并对板框密封性、滤板出液小孔直径、滤饼脱水方式进行了优化改造。实施后,显著增强了板框间的密封性,提高了滤腔内滤液的流动效率,杜绝了有害气体外溢的现象。效果显著,在湿法冶金行业具有很好的推广价值。     

冷轧废水COD催化快速测定方法改进

通过大量试验证明对化学耗氧量催化快速测定方法进行改进,能够及时准确地测定COD,能大大缩短测试时间,及时有效指导生产。     

铁氧体沉淀法处理工业含铍废水

采用碱沉淀与铁氧体沉淀相结合的工艺对含铍废水进行处理,考察了碱沉淀剂、铁氧体、沉淀反应pH、聚铝等对铍去除效果的影响。结果表明,在氢氧化钙投加量3.6kg/m3、铁氧体投加量0.05kg/m3、沉淀反应pH=8～9、聚铝投加量0.1kg/m~3的条件下,处理铍浓度为2 438μg/L的工业废水,出水铍浓度稳定低于2.7μg/L,铍去除率达到99.9%,出水满足国家污水综合排放标准要求。     

反硝化细菌去除铀矿山废水中硝酸盐

为了从不同环境中筛选得到反硝化能力强的菌株,研究碳源、温度、pH、C/N和铀浓度对菌株脱氮作用的影响,在最佳条件下得到菌株的生长曲线。结果表明：筛选得到了3株高效的反硝化细菌,菌株YWSY21在以无水乙酸钠为最佳碳源时,硝酸盐氮去除率达到97.11%,菌株4和5以柠檬酸钠为最佳碳源时对硝酸盐氮的去除率大于95%。Klebsiella variicola strain 21在温度26.31 ℃、pH=5.74、C/N=12.95最佳条件下,硝酸盐氮去除率为90.77%;Pseudomonas nitroreducens strain 4在温度25.39 ℃、pH=5.90,C/N=10.16最佳条件下,硝酸盐氮去除率为89.27%。菌株5在5种铀浓度下,NO3--N的去除率均大于85%。在最佳生长条件时,菌株4最优脱氮条件下的生长曲线具有较高的生长活性。为铀矿山硝酸盐废水的生物修复提供了菌源保障。     

Removal of Heavy Metals from Automotive Wastewater by Sulfide Precipitation

The United States Environmental Protection Agency has proposed new categorical pretreatment effluent standards for the Metal Products and Machinery Industry, which are more stringent than current discharge limits in the automotive industry. Therefore, this study was conducted to evaluate metal-sulfide precipitation chemistry as an alternative to metal-hydroxide precipitation chemistry for removing Cu, Ni, Pb, and Zn. There were three aspects of this study: (1) theoretical analysis of both metal–hydroxide and metal–sulfide chemistry; (2) experimental evaluation of commercially available sulfur-containing precipitants using deionized water; and (3) experimental evaluation of the precipitants using wastewater samples from three automotive manufacturing plants (transmission, engine, and assembly plants). The primary findings are: (1) In theory, metal–hydroxide chemistry can achieve the proposed standards when no chelating agents are present. This is not true when as small as 1 mg/L of ethylenediaminetetra-acetic acid (EDTA) is present. (2) Metal–sulfide precipitation chemistry could achieve solubility limits lower than those of metal–hydroxide chemistry over a wide range of pH. However, EDTA could still inhibit precipitation of Ni, Pb, and Zn to concentrations above the proposed standards. (3) The experiments with wastewater samples showed all precipitants removed Cu well while Ni and Zn were not well removed. The sample from transmission and engine plants were more difficult to treat than from an assembly plant, suggesting that it might have had more chelating agents. The commercially available precipitants did not perform any better than sodium sulfide. (4) Costs for using the precipitants were estimated to range from <$1/1,000 gal to >$5/1,000 gal depending on the precipitant.     

Precipitative Removal of Fluoride from Electronics Wastewater

Synthetic wastewater was used for the investigation of main factors affecting F? removal performance. The existence of SiF2?6 or PO3?4, and a low initial F? concentration were the main causes of low and unstable F? removal. Lowering the pH reduced the adverse effects of SiF2?6 and PO3?4, and adding over 4 mg∕L?1 of freshly formed CaF2 precipitates as seed greatly enhanced F? removal during treatment of low concentration wastewater (50 mg∕L?1 F?). The seed-generation method, in which a small portion of wastewater was first mixed with the whole dose of Ca2+ and then mixed with the remaining portion of wastewater, greatly improved F? removal performance and could be used instead of the method of adding seed. The conclusions obtained from the treatment of synthetic wastewater were verified by using several kinds of actual electronics wastewater. The pH should be lower than 9 for efficiently removing F? from wastewater having a high ratio of SiO2 to F?, and an even lower pH was needed for treating wastewater with a relatively high PO3?4 concentration. The seed-generation method was also found to be effective for such wastewater with high concentrations of PO3?4.     

Precipitation Removal of Fluoride from Semiconductor Wastewater

Chemical precipitation method utilizing calcium salts has been extensively used to treat fluoride-containing wastewater from semiconductor manufacturers. The major objective of this study was to investigate coagulation-flocculation of calcium fluoride precipitates (CaF2). Residual fluoride concentration of lower than 15?mg/L, the effluent standard, was found when molar ratio of calcium to fluoride, [Ca2+/F?], was 0.5 and pH ranged from 6.5 to 8.5. The fine precipitates of CaF2 were further flocculated by polyaluminum chloride (PAC) and anionic polyelectrolyte, polyacrylic acid (PAA) with different molecular weight, to facilitate better solid-liquid separation. Experimental results indicated that both PAC and PAA with low to medium molecular weight could remove CaF2 precipitates effectively. Satisfactory removal efficiency was achieved at lower dosage when PAC and PAA were used in combination. Recycling of CaF2 precipitates or CaF2 sludge did not enhance removal of fluoride or CaF2 precipitates. Reaction mechanisms were discussed based on zeta potential and particle size distribution.     

萃取皂化废水除COD制工业盐工艺研究

研究了皂化废水中含油量、COD浓度对皂化废水结晶盐的品质影响和Fenton氧化法降解COD工艺。结果表明,经活性炭除油后,含油量小于5 mg/L;在摩尔比n(H2O2)/n(Fe2+)=8、反应pH=3.0、双氧水浓度0.472 mmol/L、反应时间60 min的条件下,COD浓度小于217 mg/L。经上述工艺处理后的皂化水用氢氧化钠沉淀除铁,蒸发结晶可以得到白度为87.52、氯化钠纯度为95.7%、达到一级标准的工业级氯化钠盐。     

废水中硫氰酸根的脱除研究现状

含有硫氰酸盐的废水来自许多工业过程,主要是湿法冶金、浮选、煤焦化、印染纺织品、腈纶生产、光整和电镀,由于它的抗水解性和非挥发性,它对人体和水生生物有潜在的毒性,另外对于良好的水质也存在一定威胁,因此,硫氰酸盐在释放到环境前必须中和或从废水中去除。主要概述了可用于废水中硫氰酸盐的方法及其优缺点,并对其未来发展进行了展望。