二溴邻硝基偶氮胂微乳液分光光度法测定水中锌

试验了溴代十六烷基吡啶、正丁醇、正庚烷、水自制微乳溶液体系中,锌与二溴邻硝基偶氮胂的显色反应,建立了分光光度法测定水中锌的方法。在pH值为3.0的乙酸-乙酸钠缓冲溶液中,锌与试剂形成淡红色配合物,其最大吸收峰位于532nm波长处,表观摩尔吸光系数F为1.87×10^5L／（mol·cm）。在显色液中锌的质量浓度在0.003mg／L-0.350mg／L范围内符合比尔定律,检出限为0.001mg／L,水样中锌测定的RSD为1.3％-2.9％,加标回收率为95.7％-102％。     

铅冶炼企业周边大气降尘中铅、镉、砷量及其对土壤的影响

通过在2012年5月-2013年4月1个周期年内,对修复基地和对照点每月大气降尘中铅、镉、砷沉降量的监测,结果表明：修复基地大气降尘中铅、镉、砷含量明显较对照点高,年总沉降量分别是对照点的17．6倍、16．3倍和14．1倍,表明铅冶炼企业对基地大气降尘中铅、镉、砷含量影响显著;大气降尘中铅、镉、砷沉降量受位置和时间影响较大,在相距不到100 m的测点间,沉降量相差1倍以上,冬季主导风明显、地面植被少、二次扬尘大,使处于铅冶炼企业下风向的基地降尘中铅、镉、砷沉降量较大。沉降量时空不均匀与土壤污染不均匀现状一致,也验证了铅冶炼企业是基地大气和土壤重金属污染的主要来源。以降尘缸模拟土壤进行测算,结果表明大气降尘中镉对土壤污染速度最快,风险最大。     

原子吸收法测定水中锌质量控制指标研究

根据地域和监测技术代表性的筛选,在11个省份中选择了70家实验室参加测试工作,通过大量的监测数据,研究了原子吸收分光光度法测定水中锌的质量控制指标。研究表明:在0.3～1.5mg/L范围内,标准样品RSD≤3.0%,RSD’≤10.0%;浓度小于等于0.5mg/L时RE在±10.0%范围内,浓度为0.5～1.5mg/L时RE在±5.0%范围内。实际样品浓度小于等于0.05mg/L时,RD≤20.0%;浓度0.05～3.5mg/L时,RD≤5.0%。加标回收率控制范围为85%～110%。     

Sorption and desorption of carbamazepine, naproxen and triclosan in a soil irrigated with raw wastewater: estimation of the sorption parameters by considering the initial mass of the compounds in the soil

The amphipod Hyalella azteca was exposed for 28 d to different combinations of Zn contaminated sediment and food. Sediment exposure (+clean food) resulted in increased Zn body burdens, increased mortality and decreased body mass when the molar concentrations of simultaneously extracted Zn were greater than the molar concentration of Acid Volatile Sulfide (SEM_Zn-AVS > 0), suggesting that dissolved Zn was a dominant route of exposure. No adverse effect was noted in the foodexposure (+clean sediment), suggesting selective feeding or regulation. Combined exposure (sediment + food) significantly increased adverse effects in comparison with sediment exposure, indicating contribution of dietary Zn to toxicity and bioaccumulation. The observed enhanced toxicity also supports the assumption on the presence of an avoidance/selective feeding reaction of the amphipods in the single sediment or food exposures. During 14 d post-exposure in clean medium, the organisms from the same combined exposure history received two feeding regimes, i.e. clean food and Zn spiked food. Elevated Zn bioaccumulation and reduced reproduction were noted in amphipods that were offered Zn spiked food compared to the respective organisms that were fed clean food. This was explained by the failure of avoidance/selective feeding behavior in the absence of an alternative food source (sediment), forcing the amphipods to take up Zn while feeding. Increasing Zn body burdens rejected the assumption that Zn uptake from food was regulated by H. azteca. Our results show that the selective feeding behavior should be accounted for when assessing ecological effects of Zn or other contaminants, especially when contaminated food is a potential exposure route.     

铝熔炼设备及再生铝回收新技术分析

熔炼是铝合金生产过程中的重要环节.分析了铝熔炼过程中各个阶段的特点,对反射式熔铝炉各部位要求进行阐述;在反射式熔炼炉的基础上,介绍了目前再生铝行业较先进的熔炼设备——双室炉,同时提出了铝熔炼设备的发展方向.     

某矿热炉烟气余热利用系统测量与诊断

对某铁合金厂2台硅铁矿热炉烟气参数进行了现场测量,测量结果表明,测点烟气温度偏低,流量偏大.通过对原始测量数据进行筛选整理,得到了更加真实的测量结果;通过分析测量数据,诊断出导致现有余热锅炉进口烟气温度偏低的主要原因,并给出相应的对策建议.     

Chronic toxicity of ZnO nanoparticles, non-nano ZnO and ZnCl2 to Folsomia candida (Collembola) in relation to bioavailability in soil

The chronic toxicity of zinc oxide nanoparticles (ZnO-NP) to Folsomia candida was determined in natural soil. To unravel the contribution of particle size and free zinc to NP toxicity, non-nano ZnO and ZnCl₂ were also tested. Zinc concentrations in pore water increased with increasing soil concentrations, with Freundlich sorption constants K_f of 61.7, 106 and 96.4 l/kg (n = 1.50, 1.34 and 0.42) for ZnO-NP, non-nano ZnO and ZnCl₂ respectively. Survival of F. candida was not affected by ZnO-NP and non-nano ZnO at concentrations up to 6400 mg Zn/kg d.w. Reproduction was dose-dependently reduced with 28-d EC50s of 1964, 1591 and 298 mg Zn/kg d.w. for ZnO-NP, non-nano ZnO and ZnCl₂, respectively. The difference in EC50s based on measured pore water concentrations was small (7.94-16.8 mg Zn/l). We conclude that zinc ions released from NP determine the observed toxic effects rather than ZnO particle size.     

Recovery of metal values from zinc solder dross

Zinc solder dross containing 14.8% Sn, 16.3% Pb, 0.41% Al and 64.5% Zn was leached with 3% H₂SO₄ at 45°C for 1 h. Zinc and aluminum went into solution, whereas lead and tin remained with the residue. Aluminum was selectively precipitated as calcium aluminum carbonate by treating the sulphate leachate with limestone at pH 4.8. Zinc sulphate solution was either evaporated to obtain zinc sulphate crystals or precipitated as basic zinc carbonate at pH 6.8. The undissolved lead and tin were leached with 5 M hot hydrochloric acid. The major part of lead chloride ( 73%) was separated by cooling the leached products down to room temperature. From the soluble fraction, tin was recovered as hydrated tin oxide by alkylation with caustic soda at pH 2.4, while the remaining lead was separated at pH 8.5 as lead hydroxide. A process flowsheet had been suggested which involved two-stage hydrometallurgical treatment. Parameters affecting the recovery efficiency of the suggested method such as temperature, time, pH and acid: solid stoichiometric ratio were investigated. Results obtained revealed that the optimum leaching conditions were achieved by using 20 ml of 3% H₂SO₄ acid/g dross for 1 h at 45°C. Recovery efficiency of the metal salts was 99.1, 99.4, 99.6 and 99.5% for Zn, Al, Pb and Sn respectively. Recovery efficiency was related to the solubility of the concerned salts under the given experimental conditions.     

湿法冶锌废渣中有价金属回收研究进展

综述了电化学法、沉淀法、吸附法、离子交换法、浮选法和液膜分离法等在分离回收湿法冶锌废渣中有价金属及相关领域的研究进展,阐述了吸附法和液膜分离法的原理,指出了湿法冶锌废渣中有价金属回收的研究方向:吸附法拥有巨大的潜力,是今后的研究重点;离子交换法的研究热点是开发新型树脂基体;液膜分离法的研究方向一是提升液膜稳定性,二是研发能够高效单一分离有价金属的载体。