Feasibility study of photoelectrochemical degradation of methylene blue with three-dimensional electrode-photocatalytic reactor

The photoelectrochemical degradation of methylene blue in aqueous solution was investigated with three-dimensional electrode-photocatalytic reactor. It was found that the methylene blue could be degraded more efficiently by photoelectrochemical process than by photocatalytic oxidation or electrochemical oxidation alone. The decolorization efficiency and COD reduction were 95% and 87% for a photoelectrochemical process, respectively, while they were only 78% and 68% for a single electrochemical process and 89% and 71% for a single photochemical process. The TOC reduction of the former also reached as high as about 81% within a reaction time of 30.0 min. And these degradation reactions conformed to pseudo-first-order kinetics.     

Performance of three-phase three-dimensional electrode reactor for the reduction of COD in simulated wastewater-containing phenol

The removal of chemical oxygen demand (COD) from wastewater-containing phenol was investigated using three-phase three-dimensional electrode reactor. Special attention was paid to experimentally probe the performance of the reactor in COD removal in the process of repeated batch runs. The experimental results showed that the reactor could remove COD from phenol-containing wastewater much more efficiently than both granulated activated carbon (GAC) adsorption bed and conventional three-dimensional electrode. For 200th batch run, the three-phase three-dimensional electrode reactor with an airflow of 5 l min(-1) and a cell voltage of 30 V could remove 1350 ppm COD from the wastewater in 30 min while conventional three-dimensional electrode reactor with a same cell voltage and GAC adsorption bed with a same airflow only could remove 610 and 1000 ppm, respectively, at the same reaction duration. Although it was found that COD removal decreased with increasing repeated batch runs in our experimental range, due to adsorption saturation of GAC and electrode passivation, the extent of decrease for the three-phase three-dimensional electrode is much less than those for conventional three-dimensional electrodes and GAC adsorption beds. The passivated reactor could be partly re-activated by electrolysis in the presence of MnO2.     

土地利用类型的分维值和稳定性指数空间变异分析

土地利用类型是一种在自然和人类活动双重作用下的产物,具有不规则、相对不稳定性和复杂性特征,可以利用分形方法进行探讨;分形理论在土地结构研究中的应用涉及土地利用类型分数维的计算、土地利用结构分形研究方法、土地利用结构及其动态变化的分形描述、区域景观结构的分形模型等方面;但土地利用类型的分形机制的空间差异研究少见报道。综合考虑广东省的自然地理环境和社会经济发展状况,文章选择韶关、潮州、汕头、广州作为不同类型区域的代表,基于分形理论计算了耕地、园地、林地、草地、居民点及工矿用地、道路用地、水体和未利用土地8种地类分维值(D)和稳定性指数(Si)以及平均分维值和稳定性指数,从影响土地利用结构的地貌和人文因素两个方面出发,对比和分析了地域之间的D值、Si值的关系,并从中得到了D值和Si值的变化规律。结果表明:(1)复杂的地貌类型是影响土地利用类型D值和Si值的最主要因素;(2)社会经济发展水平一定程度上影响土地利用类型的分维值和稳定性指数;(3)区域土地利用类型的平均分维值、稳定性指数的大小是土地利用结构的综合反映。     

海洋微藻活体及乙醇固定状态下基因组DNA的微量提取方法

探讨了海洋微藻活体及固定状态下基因组DNA的提取方法,即作者改进的CTAB法.结果表明,CTAB改进法提取的基因组DNA蛋白质、酚、盐和小分子的污染较少,多糖成份也得到了有效去除.用5%乙醇固定样本提取DNA的效果最好,对原生动物抑制效果也较明显;10%以上的乙醇可杀死原生动物,但对DNA的降解率较大;30%以上的乙醇对细菌抑制较明显,但DNA都有较大程度的降解.本法提取的DNA可用于正常的酶切和PCR.用甲醛、甲醇/冰醋酸等其它固定液固定样品,DNA的得率低或者质量和纯度低.图7表1参27     

Electrically enhanced photodegradation of an azodye(Acid Orange II) using a Pt/TiO_2 film electrode irradiating with an UV lamp

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｐｒｉｎｔｉｎｇａｎｄｄｙｅｉｎｇｉｎｄｕｓｔｒｙｈａｓａｈｉｇｈｐｏｔｅｎｔｉａｌｅｎｖｉｒｏｎｍｅｎｔａｌｉｍｐａｃｔ,ｐｒｉｎｃｉｐａｌｌｙｄｕｅｔｏｔｈｅｒｅｌｅａｓｅｏｆｌａｒｇｅｖｏｌｕｍｅｓｏｆｗａｓｔｅｗａｔｅｒｔｈａｔｃｏｎｔａｉｎｈｉｇｈｏｒｇａｎｉｃｃｈａｒｇｅａｎｄｓｔｒｏｎｇｃｏｌｏｒａｔｉｏｎ .Ｔｈｅｒｅａｒｅｍａｎｙｐｒｏｃｅｓｓｅｓｔｏｔｒｅａｔｗａｓｔｅｗａｔｅｒｆｒｏｍｐｒｉｎｔｉｎｇａｎｄｄｙｅｉｎｇｉｎｄｕｓｔｒｙ ,ｂｕｔｔｈ…     

废塑料的回收利用及降解塑料的生产现状

介绍了废塑料的再生利用，热分解回收低分子化合物和焚烧回收热能的技术，并对国内降解塑料的生产现状进行了评述。     

对我区城市环境综合整治定量考核工作的回顾与思考

本文对1996-2000年全区城市环境综合整治定量考核工作进行了全面的分析，介绍了目前“城考”工作的状况，总结了经验，对今后的“城考”工作提出了建议。     

植树造林缓解温室效应的再认识

植树造林已普遍作为减缓全球变暖的主要对策之一,其主导思想是利用森林的光合作用吸收大气中的CO_2。目前很少人注意到缓解全球变暖的另一种途径,即从森林生物量中获取替代矿物燃料的生物能源。     

固定化聚铝的制备及在纸品加工废水处理中的应用

经水解尿素均匀沉淀 灼烧 ,在素瓷表面制备可能有共价结合的铝胶膜 ;铝胶薄膜载体与经复分解反应制得的氯化铝悬浊液共熟化 ,在其表面生成聚铝 ,经烧结进一步固化而制得固定化聚铝絮凝剂。经三级固定化絮凝剂床处理 ,纸品加工废水的COD、BOD、悬浮物、硫化物、色度等指标可分别降低 93 %、77%、97%、94%、80 %。     

不安全动作与不安全物态的判定方法探讨

根据事故致因"2-4"模型,人的不安全动作与物的不安全状态是事故发生的直接原因,但国内外学者关于二者的判定方法并未形成共识。为了寻找不安全动作与不安全物态科学的判定方法,首先,通过文献研究,综述了国内外学者对不安全动作、不安全物态的分类及定义;其次,从理论层面论述了不安全动作、不安全物态的判定方法;最后,以一起重大瓦斯爆炸事故为例对不安全动作及不安全物态的判定方法进行实证分析。结果表明,基于事故致因"2-4"模型的不安全动作和不安全物态判定方法有效。