低品位氧化锌矿的碱法浸出研究进展

随着世界对锌的需求量的增加,碱法浸出低品位氧化锌矿因其显著的优点（浸出率达90%以上、环境污染小等）而成为国内外研究的热点。本文主要介绍了低品位氧化锌矿氢氧化钠浸出体系的动力学和热力学过程,氨浸体系中氯铵、碳铵、硫氨浸出的国内外各研究单位的最近研究成果,并对碱浸过程中矿石活化、闪锌矿难溶解两类问题进行了讨论。     

碱消解-火焰原子吸收分光光度法测定固体废物中六价铬的干扰消除试验研究

测定固体废物实际样品中的六价铬时,往往存在着三价铬的干扰。利用传统的酸消解前处理无法有效地去除三价铬的干扰。运用碱消解前处理虽然可以消除三价铬的干扰,但由于前处理过程中,溶出液有色且基本为黄色,对二苯碳酰二肼分光光度法造成较大干扰。故建立碱消解一火焰原子吸收分光光度法,本方法不仅解决了三价铬的干扰,并避免了溶出液对测定结果造成的误差。     

聚氨酯生物膜载体处理高氨氮废水的研究

利用NaOH对聚氨酯泡沫塑料进行碱解扩孔处理,研究其作为微生物膜载体应用于曝气生物滤池,处理高氨氮模拟废水的效果。泡沫经ω=8%NaOH溶液处理0.5、1和1.5 h,结果表明:扩孔后的聚氨酯载体在孔隙率、持水倍率等方面都有所提高。碱解0.5 h对聚氨酯处理效果最好,孔隙率达到93.4%,持水倍率达到31.4。碱解扩孔处理聚氨酯泡沫载体亲水性能良好,微生物负载量达到264.35 mg/g,具有较高的微生物负载量。使用扩孔前后的聚氨酯泡沫作为微生物固定化载体用于模拟废水处理时,对于污水各指标的去除效果表明,对COD、NH4+-N等均具有较好的降解性能。     

炼油碱渣废水中硫化物去除技术的研究进展

简单介绍了炼油碱渣废水的来源及特点,综述了近年来炼油碱渣废水中硫化物的去除技术(包括沉淀技术、氧化技术、生物技术、超声波技术、电化学技术等)的研究进展。结合各技术的特点分析指出:以催化氧化为核心,以高效、经济、条件缓和为主要目标的组合工艺的优化与集成以及新型催化剂的研发,是炼油碱渣废水中硫化物去除技术的发展趋势。     

用CO_2改性碱渣废水强化炼油废水的硝化效能

针对炼油废水缺乏碱度而硝化效能受限问题,以CO_2曝气处理后的改性碱渣废水为碱度补充剂,按一定配比加入炼油废水好氧阶段以强化硝化效能。实验结果表明:经流量为1 L/min的CO_2连续曝气处理5 h后,碱渣废水p H可降至7.2~7.8,钙元素质量浓度可降低90.65%,并去除了部分汞、砷等有毒重金属;将该改性碱渣废水以1∶99的体积比加入炼油废水并进行生化处理,COD去除率可达90.2%;相较于未补充碱渣的炼油废水,出水ρ(NO3--N)提高25%~30%,硝化细菌菌群密度增加52%,污泥絮体形态结构未发生改变。     

淀粉-丙烯酰胺接枝共聚物的水解特性及絮凝性能研究

研究了淀粉-接枝-聚丙烯酰胺(St-g-PAM)的水解特性及其絮凝处理效能,并与相近分子量阴离子型聚丙烯酰胺产品作比较.结果表明,无论单独使用还是与无机絮凝剂复配使用,阴离子型淀粉-丙烯酰胺接枝共聚物的处理效果均优于阴离子型聚丙烯酰胺;淀粉-丙烯酰胺接枝共聚物的水解度大于1 7%时水解度对絮凝处理效果的影响不大,且絮凝处理效果均很好,而聚丙烯酰胺的最佳水解度为30%,大于或小于该值絮凝处理效果都会明显变差.     

碱消解-HPLC同时测定土壤中的无机汞和甲基汞

建立了碱消解-高效液相色谱(HPLC)同时测定土壤中无机汞和甲基汞的分析方法。试验研究了KOH/甲醇提取液浓度、消解时间以及反萃取剂Na2S2O3浓度对碱消解过程中甲基汞提取率的影响,当KOH/甲醇提取液浓度为25%、消解时间为12 min、Na2S2O3浓度为0.01 mol/L时,KOH/甲醇溶液对土壤甲基汞的提取率最高。提取出的无机汞和甲基汞,经衍生后HPLC法测定,流动相最佳选择为0.01 mol/LTBABr和0.025 mol/L NaCl的水溶液:甲醇=45:55(v:v)。在优化检测条件下,土壤样品中无机汞和甲基汞的检出限分别为1 ng/g和10 ng/g。该方法样品前处理简单、线性范围宽、精密度高、准确性好,适用于土壤中汞化合物的形态分析。     

The effects of high metal concentrations in soil-compost mixtures on soil enzymes

The study was undertaken to determine the impact of high-metal composts on the activities of four soil enzymes. High concentrations of metal salts (Cr, Cu, Ni or a Co-Mo-Pb combination) were added to feedstocks during the thermophilic stage of composting. These four metal-enriched composts and an unamended control compost were then mixed with soil collected from long-term agriculture plots under organic management or conventional management. The compost-soil mixtures were prepared at two rates (1:1 or 1:3 compost:soil, v/v) and incubated at 20°C for three weeks. These 20 combinations plus the five composts and the two soils were added to pots and incubated for three weeks. Following incubation, soil enzyme activities (acid phosphatase, arysulfatase, dehydrogenase, phosphodiesterase) were measured using traditional assay procedures. Compared to the control, none of the high-metal composts inhibited soil enzyme activity. Notably, the Cu compost treatment produced significantly higher activity of all four enzymes in the soil compared to the control. Previous soil management influenced the activity of three enzymes, arysulfatase and dehydrogenase had greater activity in the organic soil while phosphatase activity was greater in the conventional soil. Increasing the proportion of compost in the pot had a positive effect on phosphodiesterase activity only. In conclusion, the high-metal compost treatments either enhanced or caused no adverse effects on soil enzyme activity.     

Effects of two organophosphorus insecticides on some biochemical constituents in the nervous system and liver of rabbits

Abstract

Male Baladi rabbits were acutely and sub‐chronically intoxicated with cyanofenphos and profenophos. The levels of cholesterol, triglycerides, B‐lipoproteins and total proteins were determined in the serum, brain, spinal cord and sciatic nerve of rabbits. Moreover, the activities of alkaline phosphatase, acid phosphatase and glutamic‐pyruvic transaminase were determined in the liver of the animals. The whole Studie revealed that the biochemical constituents were highly affected by the tested insecticides. Also, the liver function suffered from adverse effects of the tested insecticides.     

Effects of metolachlor on activities of enzymes in a malaysian soil

Abstract

Effects of metolachlor on the activities of cellulase, phosphatase, urease and protease in a loamy sand soil, were evaluated for up to 28 days. Metolachlor at 10 ppm and above caused a reduction in phosphatase and urease activities for the entire period of study. The cellulase activity decreased during the very first day of incubation compared to that of the control but a recovery trend was obvious at all concentrations from day 14 onwards. Protease activity was also reduced in the metolachlor treated soil and the lower activity was observed during the entire study.