硼氢化钠还原法处理化学镀镍废液

采用硼氢化钠作为还原剂处理化学镀镍废液。研究了硼氢化钠投加量、反应时间、温度及pH对镍处理效果的影响。试验表明，投加一定量硼氢化钠溶液，控制pH为6、温度为50℃，反应10min后可以将废液中的镍由6000mg/L降至10mg/L以下。每升废液可获得54g淀淀物，其中镍质量分数达到66.1%。     

溶剂萃取法提取电镀污泥氨浸出渣中的金属资源

研究硫酸浸出Ｐ５０７－煤油－硫酸体系萃取分离铁,钠皂－Ｐ２０４－煤油－硫酸体系共萃铬、铝、反萃取分离铬、铝工艺回收电镀污染氨浸渣中的金属。通过优化实验,确定了全流程的最佳工艺参数。结果表明,铁铬渣中的金属铬、铝和铁均可以高纯度盐类形式回收,可作为化学试剂使用,回收率达９５％以上。     

Proposal for new best estimates for the soil solid–liquid distribution coefficient and soil-to-plant transfer of nickel

The objective of this study was to compile data, based on an extensive literature survey, for the soil solid–liquid distribution coefficient (K_d) and soil-to-plant transfer factor (TF) for nickel. The K_d best estimates were calculated for soils grouped according to texture and organic matter content (sand, loam, clay and organic) and soil cofactors affecting soil–nickel interaction, such as pH, organic matter, and clay content. Variability in K_d was better explained by pH than by soil texture.     

Di（2-ethylhexyl）phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater

Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconutoil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 × 10-9 to 8.9 × 10-9 mol/(m2·s) within the Cu(II) concentration range 7.8×10-4-78.6×10-4 mol/L at pH of 4.0 in the feed and 12.4 × 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10-9 mol/(m2·s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10-4 mol/L D2EHPA (membrane) in 0.5 (m pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II). rane. It     

Heavy metal removal and cyanide destruction in the metal plating industry: an integrated approach from egypt

Wastewater produced from a metal plating is a major environmental problem. Industrial auditing revealed that the main source of pollution mainly originated from rinsing water. The characterization of final effluent showed that it is highly contaminated with hazardous heavy metals and cyanide. The concentration of copper, hexavalent chromium, nickel, and cyanide in the rinsing water of metal plating department was 14.8, 40.9, 13.3, and 19 mg/l, respectively. The concentration of cyanide and zinc from the galvanizing department reached 60 and 80 mg/l. The remediation scheme included the application of in-plant control measures via changing the rinsing process followed by the destruction of cyanide and reduction of hexavalent chromium bearing wastes. The pretreated wastes were then mixed with other industrial wastes prior to a combined chemical coagulation-sedimentation using lime and/or lime in combination with ferric chloride. The results indicated that, after applying the waste minimization measures alone at the source, prior to final treatment of industrial waste, removal rates of cyanide, copper, nickel, and chromium concentrations were 23.2%, 14.9%, 32.3%, and 55.3%, respectively in the rinse water from metal plating department. Furthermore, the removal rates of cyanide and zinc in the galvanizing department reached 59.7% and 24.3. The integrated control measures and treatment scheme led to more than 99% removal of copper, nickel, chromium, and zinc, while the complete removal of cyanide was achieved in the final effluent.     

Use of diffuse reflectance spectrometry in spot test reactions for quantitative determination of cations in water

Diffuse reflectance spectroscopy can be successfully used for the quantitative determination of small amounts of pollutants like metals. The remission function was found to be linearly proportional to the concentration, when we applied the Kubelka–Munk equation. The color reactions of Cu(II), Co(II), and Ni(II) with dithiooxamide, were realised on filter paper. Reaction between Fe(III) and ammonium thiocyanate was realized on filter paper and gelatine matrix. All measurements were accomplished with a laboratory-constructed reflectometer. We have obtained a calibration curve by plotting the optical density of reflectance A_R vs log of the mol l⁻¹ concentration. Limits of detection at the 10⁻⁴ M level were estimated for all the compounds. Linear dynamic range extend over one order of magnitude and shows the potential of device for the quantitative analysis of environmental pollutants.     

浅析某厂化学镀镍线的主要污染物及处理措施

某厂化学镀镍线产生的主要污染物为大气污染、水污染和固体废物污染。其中大气污染物主要为硫酸雾。水污染物为总镍、总铜、化学需氧量、悬浮物、总磷、氨氮等。固废废弃物均为危险废物,包括废包装材料、酸性废液、含镍废液。该文分析了化学镀镍线产生的废气、废水和固体废物的主要来源,并提出了防止污染的对策。     

电弧离子镀TiN涂层沉积工艺研究

目的优化电弧离子镀沉积TiN涂层的制备工艺,分析不同N_2/Ar条件对涂层微观结构和力学性能的影响机制,进一步强化和研究TiN涂层的优异性能。方法采用带有附加线圈磁场的电弧离子镀技术在不同N_2/Ar条件下制备TiN涂层,利用扫描电子显微镜、X射线衍射仪、超景深显微镜、维氏硬度计、薄膜应力仪和高温摩擦机观察涂层微观结构、测试力学性能。结果随着N_2/Ar流量比的增加,涂层表面形貌得到改善,大颗粒的数量和尺寸明显减少,表面变得光滑致密。TiN涂层的生长取向由沿(110)晶面择优生长,逐渐转变为沿(111)晶面择优生长。涂层显微硬度呈上升趋势,硬度最高为2260HV;当N_2/Ar流量比为2:1时,摩擦系数最低为0.71,磨损率最低为1.5×10~(-2)μm~3/(N·μm),磨痕边界清晰,大颗粒和磨屑较少。结论当N_2/Ar流量比为2:1时,TiN涂层结构致密,且具有最佳的各项力学性能。     

Reuse of Fenton sludge as an iron source for NiFe2O4 synthesis and its application in the Fenton-based process

The potentially hazardous iron-containing sludge from the Fenton process requires proper treatment and disposal, which often results in high treatment cost. In this study, a novel method for the reuse of Fenton sludge as an iron source for the synthesis of nickel ferrite particles(NiFe_2O_4) is proposed. Through a co-precipitation method followed by sintering at 800°C, magnetic NiFe_2O_4 particles were successfully synthesized, which was confirmed by powder X-ray diffraction(XRD), scanning electronic microscopy(SEM), energy dispersive spectroscopy(EDS), Fourier transform infrared spectroscopy(FT-IR) and Raman spectroscopy. The synthesized NiFe_2O_4 could be used as an efficient catalyst in the heterogeneous Fenton process. In phenol degradation with H_2O_2 or NiFe_2O_4 alone, the phenol removal efficiencies within the reaction time of 330 min were as low as 5.9% ± 0.1% and 13.5% ±0.4%, respectively. However, in the presence of both NiFe_2O_4 and H_2O_2, phenol removal efficiency as high as 95% ± 3.4% could be achieved, indicating the excellent catalytic performance of NiFe_2O_4 in the heterogeneous Fenton process. Notably, a rapid electron exchange between_Ni II and_Fe III ions in the NiFe_2O_4 structure could be beneficial for the Fenton reaction. In addition, the magnetic catalyst was relatively stable, highly active and recoverable, and has potential applications in the Fenton process for organic pollutant removal.     

Development and validation of abiotic ligand model for nickel toxicity to wheat (Triticum aestivum)

A terrestrial biotic ligand model (t-BLM) was developed to predict nickel toxicity to wheat (Triticum aestivum) root elongation in hydroponic solutions. The competitive effects of five major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺ and H⁺) on Ni toxicity were investigated and Mg²⁺ was found to be a strong competitor, while H²⁺ showed less competing effect. Besides free Ni²⁺, the toxicity induced by the species NiHCO₃⁺ was non-neglect able at pH > 7 because NiHCO₃⁺ occupied a significant fraction of total Ni under such condition. Thus, a t-BLM including Ni²⁺, NiHCO₃⁺, Mg²⁺, and H⁺ could successfully predict the nickel toxicity to wheat root elongation and it performed better prediction than the conventional free ion activity model. In addition, the model was examined with two sets of independent experiments, which contained multiple cations and low-molecular-weight organic acids to mimic the rhizo-sphere condition. The developed t-BLM well predicted nickel toxicity in both experiments since it can account in both complexation and competition effects, suggesting its potential to be used in a complicated matrix like soil solution. This study provides direct evidence that the t-BLM is a reliable method for the risk assessment of nickel in terrestrial system.