电镀废水再循环中的离子交换法

已除去阳离子的废水直接加入弱硷离子交换床的离子交换树脂IRA67中。阳离子交换术用5％H_2SO_4再生。阴离子交涣床用10％NaOH再生。再生废液的前后部分再循环到未处理废水中,以提高再生废液浓度。计算机分析表明:把含铬酸盐约23％的再生废液再循环到未处理废水中,使回收后的铬酸盐浓度浓缩到两倍,即从含Cr~(+6)25g/dm~3左右提高到含Cr~(+6)47g/dm~3。这样的浓度可以直接补充到电镀槽。     

典型离子交换水处理技术在低浓度氨氮回收中的应用分析

离子交换技术具有交换容量高、能耗低、可再生效率高、操作过程简单、环境友好,并且能同时实现水质净化和资源原位回收等优势,在水处理领域应用十分广泛。在文献及工程调研的基础上,综述了3种典型离子交换剂:沸石、粉末树脂、磁性离子交换树脂的技术原理及其在污水处理中的应用现状;分析了三者在低浓度氨氮回收过程中存在的问题,并提出了相应的研究策略;评价了3种离子交换剂在工程化应用中的经济性,主要介绍了成熟的磁性离子交换树脂工艺;通过分析可知,将离子交换技术从污水治理领域应用到污水中低浓度氨氮原位富集回收领域,对污水全面资源化利用具有重要意义。     

污泥中重金属的去除及回收试验

论述了利用离子交换技术循环使用柠檬酸去除污泥中重金属,并置换回收重金属的适宜工艺条件.经柠檬酸处理后,污泥中90%以上的重金属被去除;柠檬酸处理液中的重金属用离子交换法回收,考察了树脂种类、流速、操作方式等因素对离子交换、再生效果的影响;在适宜工艺条件下,重金属的交换率均为100%,而洗脱率均接近90%;柠檬酸及离子交换树脂循环使用,重金属也得到回收,降低了处理成本.     

离子交换法选择性回收污泥厌氧消化液中的磷

为探讨高效选择性回收污泥厌氧消化液中磷的离子交换方法,采用静态实验和动态实验研究了4种阴离子交换树脂（D213、D202、D301和DSQ）的磷回收性能,筛选了适合富磷污泥厌氧消化液选择性磷回收的高交换容量树脂。实验结果表明,D213、D202、D301和DSQ 4种树脂对正磷浓度为70 mg/L的厌氧消化液进行动态处理时,其最大穿透体积分别为3、7、17和90 BV;DSQ树脂磷交换容量远高于其他3种树脂,达到6 860 mg P/L湿树脂,是目前报道的高磷交换容量树脂的3~4倍;DSQ树脂能有效地抵抗厌氧消化液中有机质和硫酸根等阴离子的干扰;用NaOH溶液再生DSQ树脂并回收磷,磷洗脱率超过96%,洗脱液是高浓度含磷液,可作为磷矿石的优质替代品。研究表明,DSQ树脂是一种高效选择性分离磷的树脂,适用于污泥厌氧消化液的磷回收。     

离子交换法含铬废水处理系统中再生液的配制和输送方式的改进

用离子交换法处理合铬废水时,阳离子交换树脂再生剂多用盐酸溶液,阴离子交换树脂再生剂多用氢氧化钠溶液.目前大多数单位使用浓度为30%的坛装盐酸,至于氢氧化钠,一般使用桶装液体(浓度大于45%),也有用固体的.这些酸、碱腐蚀性强,若用人工搬抬,手工配制,不仅劳动强度大,而且对操作者的人身安全危害很大,故急需改进酸碱液的配制和输送方法.除手工方式以外,目前使用的方法大致有以下几种:     

焦磷酸镀铜废水的处理

我厂采用焦磷酸镀铜工艺,每天排放含铜废水约20吨,锕离子含量5～30毫克/升。结合我厂多年来使用移动床离子交换法处理含铬废水的经验,在80年年底研制成功了组装式移动床离子交换含铜废水净化器,处理焦磷酸镀铜废水。该装置采用框架结构,长1400毫米,宽1100毫米,高2300毫米,占地115平方米。装有水泵、过滤器、交换柱、再生柱、树脂储存斗、再生系统以及电源控制部分等。废水经处理后变成无色、无臭的清水,pH 近中性,经比色分析,检验不出 Cu~(2 ),可作电镀车间洗涤用水循环使用。根据使用情况,树脂一般4～6天饱和排放再生一次。     

静态电渗析法回收酸洗废水中的酸和铁

为了达到盐酸酸洗废水零排放的要求,采用单张阴离子交换膜静态电渗析技术,进行了回收酸洗废水中的酸和铁的实验研究.实验时,根据实际盐酸酸洗废水水质配制模拟废水,分别调整槽电压、电解时间、阴极液pH及Fe2+、阳极液pH进行条件筛选,定时分别自阴、阳极室取样,并分析样品的pH及Fe2+浓度,根据实验结果计算Fe回收率.研究表明,采用不锈钢阴极,钛基锡锑金属氧化物涂层阳极,选用DF120型均相阴离子交换膜,当槽电压为10 V,阴极液pH为2.50～3.00,Fe2+为1 000～1 300 mg/L,阳极液pH为3.00时,静态条件下电解反应240 min后,Fe的回收率可达到95%,阴极液出水pH为5.13,Fe2+小于60 mg/L,阳极液出水pH为1.43.     

D201树脂的SO_4~(2-)吸附及脱附性能

采用离子交换树脂吸附去除炼化废水中的SO_4~(2-),以静态吸附法对比凝胶型树脂和大孔型树脂的性能,并进一步探究最优树脂的SO_4~(2-)吸附和脱附再生性能。结果表明,大孔型树脂较凝胶型树脂在复杂水质情况下性能更稳定,最优树脂为D201树脂,有较稳定的饱和吸附容量和较好的吸附脱附性能。     

采用强酸型阳离子交换树脂分离铝离子和磷酸盐

三氯硫磷作为重要的农药中间体,在生产过程中可能产生高浓度Al~(3+)与磷酸盐共存的强酸性废水,有效分离Al~(3+)与磷酸盐并进一步分别对其回收利用具有重要意义。围绕上述问题,选择001×7强酸型苯乙烯系阳离子交换树脂,研究了Al~(3+)与磷酸盐在单一和共存体系下的动态吸附交换行为。研究发现,该树脂对Al~(3+)有良好的吸附性能,Al~(3+)穿透曲线表现为典型的"S"型,采用Thomas模型可以很好地模拟Al~(3+)吸附过程。当初始Al~(3+)浓度([Al~(3+)]0)为1 000 mg·L~(-1)且流速为4、6和10 BV·h~(-1)时,穿透交换容量(Al~(3+)平衡浓度为10 mg·L~(-1))分别为14.08、12.16和11.09 mg·g~(-1);磷酸盐的存在促进了Al~(3+)的交换,当体系存在4 300 mg·L~(-1)磷酸盐时,穿透交换容量分别提高了16.50%、9.61%和6.37%。对于吸附饱和的树脂,采用4%HCl溶液可达到98.3%再生率。采用阳离子交换树脂分离Al~(3+)与磷酸盐共存废水,这可能是实现二者分离与后续回收的有效手段之一。     

改性天然沸石去除水中氨氮的研究

分别采用NaCl、KCl和CaCl2对黑龙江省某市天然沸石进行改性,考察了pH值、氨氮初始浓度以及温度对改性沸石交换性能的影响,并对改性沸石的交换动力学进行了研究.结果表明,NaCl和KCl改性对沸石原矿交换容量有不同程度提高,而KCl改性后容量有所降低.pH、NH4 初始浓度以及温度对交换性能有明显影响,pH 6.0附近沸石交换容量最大;NH4 初始浓度越高,反应速度越快,相同初始浓度下,钾型沸石交换速度较快,而沸石原矿交换速度最慢.采用Langmuir型离子交换等温线进行非线性回归的结果显示,低温有利于交换反应的进行.溶液中NH4 在改性沸石上的离子交换反应可采用Vermeulen模型描述,沸石原矿拟合相关系数较差.改性沸石多次再生后,其交换容量均有所降低.     

离子交换树脂及其在废水处理中的应用

介绍了离子交换树脂及其在多种废水处理中的应用研究。离子交换树脂法处理废水具有可深度净化、处理效率高和能实现多种金属综合回收的优点，在水处理领域必将得到更为深入的应用。     

离子交换树脂的污染和复苏工艺探讨

离子交换树脂的污染是纯水制备中不可避免的。为使被污染的树脂得到复苏,恢复其应有的交换能力,文章分析了离子交换树脂被污染的各种原因和中毒的机理,介绍了鉴别污染的方法。并根据有机物污染机理和铁中毒机理采取了相应的解毒和树脂复苏的方法。结果表明:经文中工艺解毒后的树脂重新投入使用效果良好,出水电导率达到0.06μs/Ω.cm。     

Studies on electrochemical recovery of silver from simulated waste water from Ag(II)/Ag(I) based mediated electrochemical oxidation process

In the Ag(II)/Ag(I) based mediated electrochemical oxidation (MEO) process, the spent waste from the electrochemical cell, which is integrated with the scrubber columns, contains high concentrations of precious silver as dissolved ions in both the anolyte and the catholyte. This work presents an electrochemical developmental study for the recovery of silver from simulated waste water from Ag(II)/Ag(I) based MEO process. Galvanostatic method of silver deposition on Ti cathode in an undivided cell was used, and the silver recovery rate kinetics of silver deposition was followed. Various experimental parameters, which have a direct bearing on the metal recovery efficiency, were optimized. These included studies with the nitric acid concentration (0.75-6M), the solution stirring rate (0-1400 rpm), the inter-electrode distance between the anode and the cathode (2-8 cm), the applied current density (29.4-88.2 mA cm(-2)), and the initial Ag(I) ion concentration (0.01-0.2M). The silver recovered by the present electrodeposition method was re-dissolved in 6M nitric acid and subjected to electrooxidation of Ag(I) to Ag(II) to ascertain its activity towards Ag(II) electrogeneration from Ag(I), which is a key factor for the efficient working of MEO process. Our studies showed that the silver metal recovered by the present electrochemical deposition method could be reused repeatedly for MEO process with no loss in its electrochemical activity. Some work on silver deposition from sulfuric acid solution of different concentrations was also done because of its promising features as the catholyte in the Ag(II) generating electrochemical cell used in MEO process, which include: (i) complete elimination of poisonous NO(x) gas liberation in the cathode compartment, (ii) reduced Ag(+) ion migration across Nafion membrane from anolyte to catholyte thereby diminished catholyte contamination, and (iii) lower cell voltage and hence lesser power consumption.     

Technology for recovering phosphorus from incinerated wastewater treatment sludge.

A bench-top study of phosphorus-recovering technology from ash associated with incinerated wastewater (sewage) treatment sludge was conducted by adding sulfuric acid to ashes for the elution of phosphorus. With the exception of lead, which is insoluble in sulfuric acid, when the pH of the ash fell below 2.0, phosphorus and various heavy metals in the ash were extracted. The study found that, when alkalis were added to adjust the pH of the ash extract to 4.0, phosphorus was subsequently recovered via filtration. Furthermore, when alkalis were added to adjust the pH to 10, the recovery of various heavy metals was observed. In addition, disposal of the remaining solution (wastewater), which consists of a relatively low concentration of salts, is not considered to be a significant issue since it is within wastewater discharge standards and has been found to be useful as an acid-treating substance.     

Effect of formaldehyde on Cu(II) removal from synthetic complexed solutions by ion exchange

The effect of formaldehyde (HCHO) on the ion exchange of Cu(II) from an equimolar EDTA (ethylenediaminetetraacetic acid, H(4)L) solution with a strong-base Amberlite IRA-400 resin was studied. Experiments were conducted as a function of the initial concentration of Cu(II) (0.5-10 mM), solution pH (1.0-6.0), HCHO concentration (0-6 vol%), and temperature (15-35 degrees C). It was shown that the amount of exchange of Cu(II), which exists in the form of complexed anions CuL(2-), increased with increasing solution pH and reached a plateau at an equilibrium pH (pH(e)) of 3.5. However, the amount of exchange decreased with increasing HCHO concentration up to 3 vol% but then slightly decreased with a further increase in HCHO concentration. Such effect of added HCHO was determined by the following two factors: the competitive exchange of HCOO(-) anions and the enhanced exchange of Cu(I) in the form of complexed anions CuL(3-). The exchange isotherm obtained at a fixed pH(e) could be well described by the Langmuir equation. The isosteric enthalpy change for the present ion exchange process was also evaluated and discussed.     

腐殖酸树脂处理含Pb2+、CU2+、Ni2+废水的研究

利用泥炭为原料制备腐殖酸树脂.在动态条件下,研究了腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的吸附效果及吸附条件.同时探讨了腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的吸附与解吸再生机理,吸附机理研究表明,腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的主要吸附形式为离子交换吸附和络合吸附.结果表明,在废水pH值为5.0～7.0,Pb2+、Cu2+和Ni2+浓度分别为50 mg/L,经腐殖酸树脂处理,Pb2+、Cu2+和Ni2+去除率可达98%以上,且处理后废水近中性.含Pb2+、Cu2+和Ni2+电镀废水经腐殖酸树脂处理后,废水中Pb2+、Cu2+和Ni2+含量显著低于国家排放标准.     

Lead removal in fixed-bed columns by zeolite and sepiolite

The removal efficiency of zeolite (clinoptilolite) and sepiolite from lead containing aqueous solutions was investigated. A series of experiments were conducted in batch-wise and fixed-bed columns. Synthetic wastewaters containing lead (50 mg l (-1)) and acetic acid (0.001 N) along with untreated and regenerated clinoptilolites and sepiolites were used in the adsorption studies. Batch tests were mainly conducted to isolate the magnitude of lead precipitation from real adsorption. Adsorption isotherms for both abstraction and adsorption were constructed. The removal of lead is found to be a sum of adsorption induced by ion exchange and precipitation of lead hydroxide. The breakthrough curves were obtained under different conditions by plotting the normalized effluent lead concentration (C/C0) versus bed volume (BV). The ion exchange capacity of sepiolite and clinoptilolite for lead removal showed good performance up to approximately 100 and 120 BV where the C/C0 remained below 0.1, respectively. The lead removal capacity of clinoptilolite bed from wastewater containing only lead yielded 45% higher performance compared to that of acetic acid partly due to a decrease in the effluent pH and consequently in precipitation. Also, the presence of acetic acid in the sepiolite column decreased the bed volumes treated by about 40%. Removal efficiency of lead-acetic system both in untreated clinoptilolite and sepiolite columns was found higher than that in regenerated columns.     

萃取技术分离工业废水中的苯胺

研究以硝基苯为萃取剂,25℃下通过盐析萃取法回收工业废水中苯胺。以静态分批实验考察了废水酸度、初始苯胺浓度、萃取剂与废水比(油水比)、萃取级数、无机盐种类(NaCl,KCl,Na2SO4,CaCl2,K2SO4)和浓度对苯胺萃取率的影响,获得了最佳操作工艺条件。实验结果表明,硝基苯盐析萃取技术可以有效回收废水中苯胺,且高pH和溶剂比有利于苯胺萃取,随着无机盐浓度的增加苯胺回收率增加。在适宜的条件下,通过盐析作用,经过五级萃取苯胺萃取率接近100%。