电气石微粉吸附水体中金属离子及其机理分析

研究了电气石微粉吸附水中Cu2＋、Pb2＋、Zn2＋的过程,讨论了吸附时间、粒度、用量和pH值等因素对吸附效果的影响,分析了电气石对含Cu2＋、Pb2＋、Zn2＋废水的吸附机理。电气石加工成超细粉体时,表面产生大量的不饱和键,在溶液中与水配位,使水发生解离生成羟基化表面,将重金属离子吸附到晶体负极,使局部金属离子浓度增高与电气石表面羟基离解而产生的氢氧根离子发生反应,形成各种沉淀或碱式盐析出,直到溶液中各种离子浓度达到平衡时为止。提出了凡是氢氧化物难溶于水的金属离子,理论上都可以使用电气石微粉进行吸附净化处理的观点。研究结果表明,电气石微粉对Cu2＋、Pb2＋、Zn2＋有较好的吸附效果。     

江西省酸雨变化特征及其与气象条件的关系

利用江西省气象部门12个酸雨监测站2007—2011年的观测资料,分析了江西省酸雨的时空分布特征。结果表明,近年来江西省酸雨污染总体上有缓和趋势。夏半年酸雨污染较轻,其中8月的污染最轻;冬半年酸雨污染较重,其中1月的污染最为严重。整个江西省都受到酸雨污染的威胁,但污染程度分布不均,江西中西部的吉安、宜春以及东北部的景德镇污染较为严重,江西中东部的鹰潭、上饶以及西部的萍乡污染较轻。通过对酸雨与气象条件的关系分析发现,江西省降雨的pH值随降雨量的增加先减小再增大,小雨、中雨和大雨的pH值较小,而暴雨和大暴雨的pH值较大。850 hPa层为北风(N)、东北偏北风(NNE)、东北风(NE)或东北偏东风(ENE)(总方向角为348.75°—78.75°)时,南昌降雨pH值较高,东南偏东风(ESE)时南昌降雨的pH值较低;850 hPa层为东风时赣州降雨的pH值较高,北风(N)时赣州降雨的pH值较低。     

2006—2010年南宫酸雨变化特征及影响因素

利用2006—2010年南宫酸雨观测资料和地面气象资料,结合邢台探空资料及天气形势,采用数理统计方法,分析南宫酸雨变化特征及不同气象条件对酸雨的影响。结果表明：近年来南宫降水平均pH值均小于4.70,酸雨频率大于50%,属于重酸雨区或较重酸雨区。降水酸性在夏秋两季较强,而酸雨出现频率则在秋冬两季较大,降水电导率冬季最大。南宫酸雨多出现在主导风向为偏东风或静风及北—西北风;高空天气系统为切变线时,酸雨及强酸雨频率随降水量级增大而增大;酸雨强度随相对湿度和逆温增加而增强。     

Tsunami travel times to New Zealand

A table is given for the intervals between the time that a tsunami propagating radially from a distant source first reaches a position 600 nautical miles from Wellington and the times when the tsunami first reaches any of 11 selected places in New Zealand.     

盐度、pH和规格对尖紫蛤(Soletellina acuta) 耗氧率和排氨率的影响

采用室内实验生态学方法,进行了尖紫蛤的耗氧率和排氨率的研究.结果表明,盐度和pH对不同规格尖紫蛤的耗氧率和排氨率影响明显.尖紫蛤的耗氧率和排氨率与盐度之间的关系可分别用二次多项式OR=-c1+d2S-d3S2,NR=C2+ d4S-d5S2表示,在盐度10时耗氧率和排氨率达到最大值,当盐度超过10时反而下降;pH 6.4-8.4时,3种规格尖紫蛤的单位体质量耗氧率和排氨率随pH升高而增强,pH大于8.4时耗氧率和排氨率降低.盐度2-18时,不同规格的尖紫蛤个体O∶N值为:8.319-14.840,平均为11.476,在14时O∶N出现峰值;pH 6.4-9.4时,不同大小的尖紫蛤个体O∶N值为:2.377-11.502,平均为8.547,在8.4时O∶N出现峰值.     

提取pH和温度对罗非鱼(Tilapia zillii)鱼鳞明胶特性的影响

以罗非鱼(Tilapia zillii)鱼鳞为原料, 考察提取pH和温度对明胶蛋白组分及其性质的影响。结果表明, 鱼鳞明胶蛋白在浸提pH大于5时容易发生酶解, pH小于3时会发生热降解, 而在pH 4下酶解和热降解均被有效抑制。在pH 4下利用40℃浸提明胶时, 蛋白的提取率只有1.84%, 提取的明胶中亚氨基酸比例低而钙、磷、钠、镁等矿物质含量高, 因而无法形成凝胶和蛋白膜。当浸提温度提高到50℃及以上时, 明胶提取率大幅增加, 明胶中亚氨基酸比例上升且矿物质含量比例下降。另外, 在pH 4、70℃下浸提的明胶其凝胶强度可达283g, 可形成机械强度为50MPa的蛋白膜, 表明该条件提取的鱼鳞明胶具有替代哺乳动物明胶的潜力。     

氨基酸在改性黏土上的吸附机制研究

研究了四种氨基酸(赖氨酸、谷氨酸、甘氨酸、组氨酸)化合物在改性黏土的吸附特征, 考察了改性剂PACl 添加比例、介质pH 及离子强度对吸附过程的影响, 并探讨了吸附机制。结果表明, 在一定比例的PACl 改性能促进氨基酸在高岭土上的吸附, 最佳改性比例为5%, 赖氨酸、谷氨酸、甘氨酸、组氨酸的最大吸附量分别为827、712.56、723.14、732.56 μmol/g; 氨基酸在改性黏土上的吸附动力学符合伪二阶动力学模型; 利用Weber-Morris 模型测定四种氨基酸内部粒子扩散常数, 5%改性条件下赖氨酸、谷氨酸、甘氨酸、组氨酸的内部粒子扩散常数分别为0.847、0.567、0.780、0.603。热力学研究表明, 氨基酸在改性黏土上的吸附等温线是C 型等温线, 5%改性条件下四种氨基酸(赖氨酸、谷氨酸、甘氨酸、组氨酸)的热力学自由能分别为?1.99、?2.41、?3.16、?2.94 kJ/mol, 说明氨基酸在改性黏土上的吸附是一个自发的吸附过程。介质pH 及离子强度对吸附过程具有重要影响。     

Settling of Kaolinite in Different Aqueous Environment

Settling characteristics of soils carry great importance for geotechnical engineers since sediments properties are formed during the settling of soil particles in an aqueous environment. In this study, settling characteristics of kaolinite are investigated. Different ionic strengths of NaCl, CaCl₂ and AlCl₃ were considered as a function of pH in aqueous environment of varying solid concentrations. Factors affecting the settling characteristics and fabric of kaolinitic sediments have been identified. The results of the study reveal that kaolinite settles in either flocculated or dispersed forms depending on pH and ion concentration. Flocculated settling occurs in acidic pH due to formation of flocs in edge-to-face structure with increasing positive charges at the particle edges. Dispersed settling occurs in alkaline pHs when ionic strength is low. When ionic strength is increased in alkaline pHs, kaolinite particles settle in flocculated form. Furthermore, the results show that pH has a significant role on the final sediment thickness or void ratio of kaolinite. Densely packed structures in alkaline and loosely packed structures in acidic aqueous environments are formed depending on pH level. Results also show that as the solid concentration increases, the settling rate decreases due to buoyancy effect. Finally, the zeta potential of kaolinite is correlated with the final sediment thickness or void ratio of kaolinite as a function of pH. This correlation proves that there is a good agreement between zeta potential and the final sediment thickness or void ratio, especially when the soil is settled in a dispersed form.     

Properties of sediments deposited in a fluid with different pH

Abstract

The effect of pH on the physical and mechanical properties of a sediment was investigated through a set of experimental tests. The sediment was formed from deposition of suspended particles in a fluid. Two different types of clay soil were suspended in fluids with different pH (2, 4, 7, 9 and 11) in cylindrical tubes with volume of 1?liter and also in special cylindrical reservoirs. The height of the sediment was measured in the cylindrical tube until equilibrium was achieved. The sediment deposited in the reservoirs was dried in air and then Atterberg limit, compaction and unconfined compressive strength (UCS) tests were conducted on samples prepared from each sediment. The results showed that the final height of the settled sediment is a function of pH; the height of sediment is increased with increasing the pH. Also, the Atterberg limits increased with increasing the pH. The maximum dry unit weight and optimum water content decreased and increased with increasing the pH. The final strength of the sediment decreased with increasing pH. Based on the SEM analysis, it was found that the values of pH influence the properties of the formed sediments.     

南京冬季辐射雾和平流辐射雾的化学特征差异

利用2006和2007年冬季南京雾外场试验中取得的雾水离子成分资料,分析了雾水化学组分特征,探讨了雾水酸度来源及辐射雾和平流辐射雾的化学特征差异。结果表明,南京冬季雾水中总离子浓度偏高,浓度最高的3种离子成份是SO^-24、NH^＋4和Ca^2＋,但雾水酸性不强,碱性离子成分的中和作用是pH值较高的原因。平流辐射雾中雾水离子总浓度约为辐射雾的2.2倍,平流辐射雾中浓度最高的阳离子为NH^＋4,辐射雾中为Ca^2＋。