氯化氢（硫氰酸汞分光光度法）测定中若干问题探讨

硫氰酸汞分光光度法测定空气中氯化氢,方法试剂空白值不稳定,曲线线性不好。现就在大气中氯化氢的测定（硫氰酸汞分光光度法）过程中遇到的若干问题作了分析和探讨,并且通过实验,证明提高硫氰酸汞的浓度,可以提高该测量方法灵敏度。     

光电催化和光产生过氧化氢联合降解苯胺

报道了在双槽光电反应器，紫外光光照二氧化钛阳极时，苯胺在阳极室降解的同时，光生电子在外加电场的作用下移动到石墨阴极上，并还原溶液中的氧生成过氧化氢氧化降解苯胺，光电催化降解污染物时，这种方法同时充分地利用了光生空穴和光生电子，因而是十分有效的。     

氨氮及H2O2对溴酸盐和消毒副产物控制的影响

本研究以南方某含溴水源为原水,利用饮用水常规工艺及臭氧-活性炭深度处理中试连续实验,评价臭氧氧化过程中溴酸盐生成情况,并考察了氨氮、过氧化氢(H_2O_2)对溴酸盐控制效果及对三卤甲烷生成势(THMFP)的去除影响.结果表明,在不同水质条件下,臭氧消耗量为1.0 mg·L~(-1)以上时,溴酸盐的生成量超过标准(10.00μg·L~(-1)).利用氨氮和H_2O_2投加均能有效控制溴酸盐生成量,且随投加量增大,溴酸盐生成量逐渐降低,氨氮投加0.10~0.30 mg·L~(-1)或m(H_2O_2)/m(O3)(质量比)为0.2~1.0时,能够将溴酸盐控制在标准以内.当氨氮-H_2O_2联合控制溴酸盐时,溴酸盐生成量随m(H_2O_2)/m(O3)先升高后降低.在利用氨氮和H_2O_2投加进行溴酸盐控制过程中,氨氮对THMFP的去除效率影响并不显著,而投加H_2O_2使得THMFP去除效能有所降低.     

Enhanced degradation of organic contaminants using catalytic activity of carbonaceous structures: A strategy for the reuse of exhausted sorbents

Generation of hydroxyl radicals (?OH) is the basis of advanced oxidation process (AOP). This study investigates the catalytic activity of microporous carbonaceous structure for in-situ generation of ?OH radicals. Biochar (BC) was selected as a representative of carbon materials with a graphitic structure. The work aims at assessing the impact of BC structure on the activation of H₂O₂, the reinforcement of the persistent free radicals (PFRs) in BC using heavy metal complexes, and the subsequent AOP. Accordingly, three different biochars (raw, chemically- and physiochemically-activated BCs) were used for adsorption of two metal ions (nickel and lead) and the degradation of phenol (100 mg/L) through AOP. The results demonstrated four outcomes: (1) The structure of carbon material, the identity and the quantity of the metal complexes in the structure play the key roles in the AOP process. (2) the quantity of PFRs on BC significantly increased (by 200%) with structural activation and metal loading. (3) Though the Pb-loaded BC contained a larger quantity of PFRs, Ni-loaded BC exhibited a higher catalytic activity. (4) The degradation efficiency values for phenol by modified biochar in the presence of H₂O₂ was 80.3%, while the removal efficiency was found to be 17% and 22% in the two control tests, with H₂O₂ (no BC) and with BC (no H₂O₂), respectively. Overall, the work proposes a new approach for dual applications of carbonaceous structures; adsorption of metal ions and treatment of organic contaminants through in-situ chemical oxidation (ISCO).     

臭氧氧化水中2,4,6-三氯酚的反应机理研究

研究了臭氧氧化对2,4,6-三氯酚的去除效果,以及氧化过程中过氧化氢、氯离子、甲酸和乙二酸的变化情况,探讨了臭氧氧化2,4,6-三氯酚的反应机理和反应途径.实验结果表明,如果溶液中没有自由基清除剂,在臭氧投加量为24mg·L~(-1)时,0·1mmol·L~(-1)的2,4,6-三氯酚在6min内,去除率可达99%.臭氧分子氧化2,4,6-三氯酚的过程中产生过氧化氢,检测到的过氧化氢的最大摩尔浓度为初始2,4,6-三氯酚摩尔浓度的22·5%.中间产物过氧化氢随后和臭氧反应生成大量的羟基自由基,此时2,4,6-三氯酚是被臭氧和羟基自由基联合氧化,生成甲酸和乙二酸.当溶液中含有大量的自由基清除剂时,2,4,6-三氯酚首先被臭氧分子氧化成黄色的氯代对苯醌,然后氧化成甲酸和乙二酸.臭氧氧化2,4,6-三氯酚存在臭氧分子氧化以及O3/OH·联合氧化两种反应途径.     

过氧化氢/草酸铁体系太阳光催化降解染料废水的研究

以过氧化氢 /草酸铁络合物作光氧化剂 ,利用太阳光对 10种水溶性染料模拟废水进行了光氧化降解试验研究 ,发现在日光照射下 ,过氧化氢 /草酸铁络合物能使染料溶液迅速降解。以活性艳蓝KN R为代表 ,研究各种因素对光降解的影响。结果表明 ,溶液pH为 2 0～ 4 0时 ,光降解速率快 ;溶液中Fe3 + 与草酸根的摩尔比为 1∶3时 ,光解效果最好 ;提高H2 O2 浓度可以提高光降解速率 ,但H2 O2 的利用率会降低。     

新型改性淀粉水处理剂在水体中的降解实验研究

研究了二硫代氨基甲酸改性玉米淀粉(DTCS)及其捕集重金属后产物在水体中的稳定性,考察了氧化剂、光催化氧化等不同方法下的降解效果.确定了降解的最佳反应条件.当氧化剂和紫外光共同作用时,降解效果更好.对降解产物的定性、定量分析结果表明,降解产物无毒,该水处理剂在水体中可安全降解.     

Characterization of redox conditions in groundwater contaminant plumes

Evaluation of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behaviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few cases have been reported. No standardised or generally accepted approach exists. Slow electrode kinetics and the common lack of internal equilibrium of redox processes in pollution plumes make, with a few exceptions, direct electrochemical measurement and rigorous interpretation of redox potentials dubious, if not erroneous. Several other approaches have been used in addressing redox conditions in pollution plumes: redox-sensitive compounds in groundwater samples, hydrogen concentrations in groundwater, concentrations of volatile fatty acids in groundwater, sediment characteristics and microbial tools, such as MPN counts, PLFA biomarkers and redox bioassays. This paper reviews the principles behind the different approaches, summarizes methods used and evaluates the approaches based on the experience from the reported applications.     

Thermal safety assessment for solid organic peroxides

The thermal hazards of dicumyl peroxide (DCP) and benzoyl peroxide (BPO), self-reactive chemicals are identified and characterized using high-pressuredifferential scanning calorimeter, and simultaneous thermogravimetric analyzer, a C80 micro-calorimeter is used. The apparent exothermic onset temperature of DCP is found to be between the range of 112–122 °C for different heating rates in DSC tests. There are two coupled peaks of BPO around 105 °C at both the heating rates of 4.0 and 8.0 °C/min while no endothermic peak showed at lower heating rates. Furthermore, another endothermic peak appears immediately after the exothermic peak at about 211 °C of DCP under high-pressure conditions. For BPO, the endothermic peak before the exothermic peak disappears as the pressure increases to 1.0 and 1.5 MPa. The average values of apparent activation energy calculated by Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods during the conversion rate between 15 and 75% of DCP are 80.69 and 74.05 kJ/mol, and that of BPO are 119.96 and 112.93 kJ/mol, respectively. According to the isothermal tests, the thermal decomposition of DCP behaviors is an n-th order reaction while BPO conforms to the laws of autocatalytic reaction.     

An Experimental Study on the Effect of Electrolytic Concentration on the Rate of Hydrogen Production

The effects of concentration of electrolytes on hydrogen production rate (HPR) at different applied voltages were experimentally evaluated in this research paper. The rate of hydrogen production was found to be directly proportional to the concentration of total dissolved solids and the efficiency did not change much with the change in the concentration of solids. Sensitivity analysis of the electrolysis system was also carried out to understand the relative importance of concentration of total dissolved solids (TDS) on the HPR, which can help for an optimum design.