碱性化学镀镍废液的净化处理

找到了一种处理碱性化学镀镍废液的新方法 ,研究了镀液组成、温度、时间、漂白粉浓度对化学镀镍废液处理结果的影响。结果表明 ,用漂白粉处理碱性化学镀镍废液是可行的。     

膜电解法从模拟酸性蚀刻废液中回收铜粉

酸性蚀刻废液是一种印制电路板制作过程中产生的强酸、高铜的工业废水,对其回收利用具有较高的经济价值。采用膜电解法处理模拟酸性蚀刻废液,在阴极区回收铜粉。研究了铜粉的形成条件,考察了阴极液铜浓度、温度和电流密度对阴极电流效率的影响。结果表明,阴极液的铜浓度在20~25 g/L,温度为45~50℃,电流密度在11~12 A/dm2,阴极的电流效率最高。随着阴极液酸度的增加,铜粉的纯度提高,但阴极电效会降低。为保证较高的铜粉纯度及阴极电效,阴极液的酸度在0.32~0.36 mol/L为宜。     

Equilibrium and kinetic modelling of chromium(III) sorption by animal bones

The paper discusses sorption of Cr(III) ions from aqueous solutions by animal bones. Animal bones were found to be an efficient sorbent with the maximum experimentally determined sorption capacity in the range 29-194 mg g(-1) that depended on pH and temperature. The maximum experimentally determined sorption capacity was obtained at 50 degrees C, pH 5. Batch kinetics and equilibrium experiments were performed in order to investigate the influence of contact time, initial concentration of sorbate and sorbent, temperature and pH. It was found that sorption capacity increased with increase of Cr(III) concentration, temperature and initial pH of metal solution. Mathematical models describing kinetics and statics of sorption were proposed. It was found that process kinetics followed the pseudo-second-order pattern. The influence of sorbent concentration was described with Langmuir-type equation and the influence of sorbate concentration was described with empirical dependence. The models were positively verified.     

碱性蚀刻废液中的铜回收

考察N910、Lix84-I、N902和RE609 4种不同类型的萃取剂从高浓度铜氨溶液中萃取铜的效率,选取萃取效果较好的N910作为重点研究对象,并研究其从铜氨溶液萃取铜的萃取性能。实验发现,N910具有萃取速率快、饱和容量高、分离效果好、反萃完全及不易萃氨等特点;并用80%N910+煤油溶液,在pH=9.5,温度25℃,相比(O/A)1∶1条件,进行真实料液萃取实验,振荡10 min,萃取中铜离子的浓度达到69.66 g/L。因此,N910能够作为一种高效的铜萃取剂,从碱性蚀刻废液中回收铜。     

Leaching of copper and zinc from spent antifouling paint particles

Leaching of Cu and Zn from a composite of spent antifouling paint particles, containing about 300 mg g⁻¹ and 110 mg g⁻¹ of the respective metals, was studied in batch experiments. For a given set of simulated environmental conditions, release of Cu was independent of paint particle concentration due to attainment of pseudo-saturation, but Zn was less constrained by solubility effects and release increased with increasing particle concentration. Leaching of Cu increased but Zn decreased with increasing salinity, consistent with mechanisms governing the dissolution of Cu₂O in the presence of chloride and Zn acrylates in the presence of seawater cations. Because of complex reaction kinetics and the presence of calcium carbonate in the paint matrix, metal leaching appeared to be greater at 4 °C than 19 °C under many conditions. These findings have important environmental and biological implications regarding the deliberate or inadvertent disposal of antifouling paint residues.     

Lix54-100从印刷电路板蚀刻废液中回收铜

本文对Lix5 4 10 0萃取剂萃取铜氨料液中铜的性能做了研究 ,发现其具有动力学速率快、饱和容量高、分离效果好、反萃容易及不萃氨等特点。并把其应用于印刷电路板蚀刻废液中铜的回收 ,在铜初始浓度为 15 6.96g/L ,相比为 2∶1条件下 ,用 80 %Lix5 4 10 0 -煤油经过三级错流萃取 ,铜的浓度可下降到 2 6.88g/L。三级总萃取率达 82 .87%。由此设计推荐了无废排放工艺流程 ,实现了经济效益和环境效益的统一     

废旧镍镉电池的生物沥滤处理——沥滤停留时间的影响研究

用污泥加硫酸化液沥滤镍镉电池中的重金属是一种全新的工艺,该工艺主要由生物酸化反应器和金属沥滤反应器两个反应器组成.生物酸化反应器中产生的酸液就是沥滤电池中重金属的反应液.研究表明,酸化液在沥滤反应池的停留时间对沥滤的效果有显著影响.在1、4、7、12 d 4个停留时间中,4 d的效果是最好的,对金属Cd和Ni都用40 d左右基本实现了全部滤除;1d略微慢一些,Cd用了40 d,Ni用了45 d;7 d和12 d的沥滤时间都长于50 d.4 d产生的金属废液量是1 d的1/4,考虑到后续处理金属沥滤废液的工作量,选择4d的停留时间要优于1d.     

电镀污泥中铜镍回收方法及工艺的研究

研究了电镀污泥中铜、镍的回收方法及工艺,采用硫酸浸出,浸出液在电压为2.4 V时电解3.5 h,铜的总回收率在99%以上,同时将Fe2 氧化成Fe3 ,电解余液(电解铜之后的溶液)加热至90℃,用磷酸盐调节pH至3.0,磷酸钠投加倍数为形成磷酸盐沉淀理论用量的1.4倍,99%的铁、铝、铬被去除.镍的总回收率约在97%以上.     

Sorption of copper, zinc and lead on soil mineral phases

Soil mineral phases play a significant role in controlling heavy metal mobility in soils. The effective study of their relation needs the integrated use of several analytical methods. In this study, analytical electron microscopy analyses were combined with sequential chemical extractions on soils spiked with Cu, Zn and Pb. Our aims were to study the metal sorption capacity of soil mineral phases and the effect of presence of iron oxide and carbonate on this property of soil minerals. Copper and Pb were found to be characterized by higher and stronger sorption on the studied samples than Zn. Only the former two metals showed significant differences in their immobilized metal amounts on the studied samples and soil mineral particles. Highest metal amounts were sorbed on the swelling clay mineral particles (smectites and vermiculites), but iron-oxide phases may also have similar lead sorption capacity. Alkaline conditions due to the carbonate content of soils resulted both in increased sorption on the mineral particles for Cu and in enhanced role of precipitation for all the studied metals. On the other hand, the intimate association of phyllosilicates and iron resulted in significant increase in metal sorption capacity of the given particle. The results of sequential extractions could be successfully completed by the analytical electron microscopy analyses for studying the sorption capacity of discrete mineral particles. Their integrated use helps us in better understanding the heavy metal-mineral interactions in soils.     

The tolerance of Empetrum nigrum to copper and nickel

The Cu and Ni tolerance of 3- to 5-year-old cuttings of crowberry (Empetrum nigrum) were tested in controlled conditions. Six levels of Cu (0.1-100 mg l(-1)), five levels of Ni (0-100 mg l(-1)) and nine levels of Cu+Ni were applied. The elongation of the shoots, new shoot and root dry weights indicated an adverse effect of increasing Cu and Ni concentrations. At low Cu levels the addition of Ni decreased the dry weights more than at high Cu levels. The results show that E. nigrum accumulated high concentrations of Cu and Ni mainly in old stem tissue, which contained a maximum of over 3000 mg kg(-1) Cu and 1000 mg kg(-1) Ni. The concentrations of Cu and Ni in E. nigrum were higher than those measured in plants growing in areas near to Cu-Ni smelters, but the accumulation pattern was similar. The survival of the cuttings was not affected suggesting that E. nigrum possesses an internal heavy metal tolerance.     

Sorption of cobalt and nickel on anaerobic granular sludges: isotherms and sequential extraction

The objective of this study was to investigate the sorption capacity and the fractionation of sorbed nickel and cobalt onto anaerobic granular sludges. Two different anaerobic granular sludges (non-fed, pH=7) were loaded with nickel and cobalt in adsorption experiments (monometal and competitive conditions). The combination of sequential extraction with the sorption isotherm analysis allowed the assessment of the sorption capacity of individual fractions present in the anaerobic granular sludges. The operational fractionation of the sorbed heavy metals was determined using a modified Tessier sequential extraction procedure. The sorption characteristics of each extracted fraction (exchangeable, carbonates, organic matter/sulfides and residual fractions) fitted well to the Langmuir model. The organic matter/sulfides fraction showed the highest affinity for cobalt and nickel in both sludges investigated compared to the other operationally defined fractions. The presence of iron negatively affected cobalt and nickel accumulation in this organic matter/sulfides fraction. The trace metals-iron sulfide interactions are likely to be the key process in controlling the distribution of cobalt and nickel during sorption onto non-fed methanogenic granules due to the high affinity of iron sulfides towards the metals studied.     

Sensitivity of Mediterranean woody seedlings to copper, nickel and zinc

The restoration of heavy metal contaminated areas requires information on the response of native plant species to these contaminants. The sensitivity of most Mediterranean woody species to heavy metals has not been established, and little is known about phytotoxic thresholds and environmental risks. We have evaluated the response of four plant species commonly used in ecological restoration, Pinus halepensis, Pistacia lentiscus, Juniperus oxycedrus, and Rhamnus alaternus, grown in nutrient solutions containing a range of copper, nickel and zinc concentrations. Seedlings of these species were exposed to 0.048, 1 and 4 microM of Cu; 0, 25 and 50 microM of Ni; and 0.073, 25 and 100 microM of Zn in a hydroponic silica sand culture for 12 weeks. For all four species, the heavy metal concentration increased in plants as the solution concentration increased and was always higher in roots than in shoots. Pinus halepensis and P. lentiscus showed a higher capacity to accumulate metals in roots than J. oxycedrus and R. alaternus, while the allocation to shoots was considerably higher in the latter two. Intermediate heavy-metal doses enhanced biomass accumulation, whereas the highest doses resulted in reductions in biomass. Decreases in shoot biomass occurred at internal concentrations ranging from 25 to 128 microg g-1 of Zn, and 1.7 to 4.1 microg g( -1) of Cu. Nickel phytoxicity could not be established within the range of doses used. Rhamnus alaternus and J. oxycedrus showed higher sensitivity to Cu and Zn than P. halepensis and, especially, P. lentiscus. Contrasted responses to heavy metals must be taken into account when using Mediterranean woody species for the restoration of heavy metal contaminated sites.     

Biosorption of copper, cobalt and nickel by marine green alga Ulva reticulata in a packed column

Biosorption of copper, cobalt and nickel by marine green alga Ulva reticulata were investigated in a packed bed up-flow column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 25 cm, the metal-uptake capacity of U. reticulata for copper, cobalt and nickel was found to be 56.3+/-0.24, 46.1+/-0.07 and 46.5+/-0.08 mgg(-1), respectively. The Bed Depth Service Time (BDST) model was used to analyze the experimental data. The computed sorption capacity per unit bed volume (N0) was 2580, 2245 and 1911 mgl(-1) for copper, cobalt and nickel, respectively. The rate constant (K(a)) was recorded as 0.063, 0.081 and 0.275 lmg(-1)h(-1) for copper, cobalt and nickel, respectively. In flow rate experiments, the results confirmed that the metal uptake capacity and the metal removal efficiency of U. reticulata decreased with increasing flow rate. The Thomas model was used to fit the column biosorption data at different flow rates and model constants were evaluated. The column regeneration studies were carried out for three sorption-desorption cycles. The elutant used for the regeneration of the biosorbent was 0.1 M CaCl2 at pH 3 adjusted using HCl. For all the metal ions, a decreased breakthrough time and an increased exhaustion time were observed as the regeneration cycles progressed, which also resulted in a broadened mass transfer zone. The pH variations during both sorption and desorption process have been reported.     

Removal and recovery of copper and nickel ions from aqueous solution by poly(methacrylamide-co-acrylic acid)/montmorillonite nanocomposites

Nanocomposite hydrogels based on poly(methacrylamide-co-acrylic acid) and nano-sized montmorillonite were prepared by aqueous dispersion and in situ radical polymerization. Optimum sorption conditions were determined as a function of montmorillonite content, contact time, pH, and temperature. The equilibrium data of Cu²⁺ and Ni²⁺ conformed to the Freundlich and Langmuir isotherms in terms of relatively high regression values. The maximum monolayer adsorption capacity of the nanocomposite hydrogel (with 3 wt% montmorillonite content), as obtained from the Langmuir adsorption isotherm, was found to be 49.26 and 46.94 mg g^?1 for Cu²⁺ and Ni²⁺, respectively, at contact time?=?60 min, pH?=?6.8, adsorbent dose?=?100 mg/ml, and temperature?=?318 K. Kinetic studies of single system indicated that the pseudo-second order is the best fit with a high correlation coefficient (R ²?=?0.97–0.99). The result of five times sequential adsorption–desorption cycle shows a good degree of desorption and a high adsorption efficiency.     

Fenton氧化-混凝联合工艺处理络合铜镍废水的研究

采用Fenton试剂氧化-混凝联合工艺对难处理络合铜镍电镀废水进行了研究,考察了废水初始pH值、H2O2初始浓度、[Fe^2＋]/[H2O2]、反应时间和温度、混凝液pH、混凝剂质量浓度对处理过程的影响,探讨了废水的降解途径和机理.结果表明,在体系初始pH=4,温度30℃,H2O2投加量为800mg/L,[Fe^2＋]/[H2O2]=0.1,反应时间60 min,混凝液pH=8及混凝剂质量浓度为500mg/L的条件下,废水的COD去除率为96.98%,Cu^2＋为99.91%,Ni^2＋为99.92%,处理水完全达到国家一级排放标准.同时依据GC/MS对X-GN降解最终产物的分析结果,推导出废水的基本降解机理和途径.     

Fenton氧化-混凝联合工艺处理络合铜镍废水的研究

采用Fenton试剂氧化-混凝联合工艺对难处理络合铜镍电镀废水进行了研究,考察了废水初始pH值、H2O2初始浓度、[Fe2 ]/[H2O2]、反应时间和温度、混凝液pH、混凝剂质量浓度对处理过程的影响,探讨了废水的降解途径和机理.结果表明,在体系初始pH=4,温度30℃,H2O2投加量为800mg/L,[Fe2 ]/[H2O2]=0.1,反应时间60 min,混凝液pH=8及混凝剂质量浓度为500mg/L的条件下,废水的COD去除率为96.98%,Cu2 为99.91%,Ni2 为99.92%,处理水完全达到国家一级排放标准.同时依据GC/MS对X-GN降解最终产物的分析结果,推导出废水的基本降解机理和途径.     

Sorption of carbendazim and linuron from aqueous solutions with activated carbon produced from spent coffee grounds: Equilibrium,kinetic and thermodynamic approach

Spent coffee grounds (SCG) have been used for the production of activated carbon (AC) by impregnation with different ratios of phosphoric acid at 600?°C, Xp (H₃PO₄/coffee): 3:1^30%, 4:1^30%, 3:1^50% and 4:1^50%. The obtained AC was characterized by BET, FTIR and SEM. BET surface area corresponds to 803.422 m² g^?1. The influences of the main parameters such as contact time, the pesticides initial concentration, adsorbent dose, pH and temperature on the efficiency of separation process were investigated during the batch operational mode. Results were modeled by adsorption isotherms: Langmuir, Freundlich and Temkin isotherms, which gave satisfactory correlation coefficients. The maximum adsorption capacities calculated from the Langmuir isotherms were 11.918?mg g^?1 for carbendazim and 5.834?mg g^?1 for linuron at room temperature. Adsorption kinetics of carbendazim and linuron have been studied by the pseudo-first-order, the pseudo-second-order and the intraparticle diffusion model. The results of adsorption kinetics have been fitted the best by pseudo-second-order model. The resulted data from FTIR characterization pointed to the presence of many functional groups on the AC surface. SCG adsorbent, as an eco-friendly and low-cost material, showed high potential for the removal of carbendazim and linuron from aqueous solutions.     

Soil mobility of sewage sludge-derived dissolved organic matter, copper, nickel and zinc

A soil (sandy loam) column leaching study aimed to determine the extent of mobility and co-mobility of Cu, Ni, Zn and dissolved organic matter (DOM) released from a surface-application (equivalent to 50 t ds ha(-1) of anaerobically-digested sewage sludge. Leaching of DOM through the soil column was found to be almost un-retarded. Decidedly similar behaviour was exhibited by Ni suggesting that it migrated as organic complexes. Whilst Cu was also found to be leached, significant retardation was evident. However, the importance of DOM in promoting the mobility of both Cu and Ni was evidenced by their lack of mobility when added to the soil column as inorganic forms. The presence of DOM did not prevent Zn from becoming completely adsorbed by the soil solid phase. In relation to WHO drinking water guidelines, only Ni concentrations showed potential environmental significance, due to the relatively poor retention of Ni by the sludge solid phase.