ZrO2负载过渡金属氧化物催化剂对CO＋NO（O2）反应的影响

本文运用固定床微反技术考察了Ｃｕ,Ｆｅ,Ｍｎ,Ｃｒ,Ｃｏ和Ｎｉ负载（ＺｒＯ２载体）氧化物对ＣＯ＋ＮＯ（Ｏ２）反应的催化活性。研究了ＮＯ和ＣＯ在不同比例时,催化剂对Ｎ２Ｏ和Ｎ２生成的影响。结果表明,在ＮＯ＋ＣＯ反应中,ＮＯ和ＣＯ的比例对催化剂活性和Ｎ２Ｏ,Ｎ２生成均有明显的影响,ＣｕＯｘ／ＺｒＯ２催化剂的活性最高;Ｎ２Ｏ是ＮＯ＋ＣＯ反应的中间产物,低温或ＮＯ过量时有利于生成Ｎ２Ｏ,高温或ＮＯ不足时有     

Fenton试剂处理选矿废水机理研究

研究了用Fenton试剂处理选矿废水中残余的黄药,分别考查了氧化时间、反应初始pH值、Fe2+浓度及H2O2用量对黄药降解效果的影响,用正交试验确定了4个因素的最好条件。结果表明:初始pH值和H2O2用量是影响去除效果的主要因素;氧化时间为60 m in,反应初始pH=4,[Fe2+]=20 mg/L,[H2O2]=20 mg/L,黄药的浓度为125 mg/L时,黄药的去除率达到99.5%;初步探讨了Fenton试剂净化废水中黄药的机理是.OH自由基先将黄药氧化为过氧化黄原酸盐,再将其氧化为CO2,黄药得到去除。     

Uptake of PAHs by cabbage root and leaf in vegetable plots near a large coking manufacturer and associations with PAHs in cabbage core

Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.     

灰霾的健康效应

灰霾是颗粒物和气体污染物导致的可察觉到的能见度降低的污染天气现象.近年来,随着城市化进程的快速发展,城市大气污染加剧,灰霾天气也随之增多.总结了灰霾这一污染型天气的特征,介绍了灰霾的化学成分、污染机制等,并从影响机制和流行病学角度出发,对国内外灰霾对人体的健康效应研究成果进行了综合评述,提出目前急需解决的科学问题和今后的研究方向.     

Photocatalytic oxidation of triclosan

In the spring of 2003, there was an outbreak of the severe respiratory syndrome (SARS) in Hong Kong. Health concerns have thus triggered an increased and predominant use of various types of household cleansing agents such as triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol). However, it has been reported recently that triclosan could be photochemically converted to toxic 2,8-dichlorodibenzo-p-dioxin (2,8-Cl(2)DD) in the environment. It is therefore necessary to develop environmentally friendly methods for the treatment of triclosan. To this end, photocatalytic degradation of triclosan in aqueous solution was conducted using TiO(2) (Degussa P25) under irradiation of UV light (lambda < 365 nm). It was found that triclosan could be degraded by this approach. Hydrogen peroxide was added to enhance the degradation process, and the optimal initial hydrogen peroxide concentration for triclosan degradation was 0.005% (w/v). Product identification indicated that triclosan oxidation occurred at its phenol moiety and yielded quinone and hydroquinone intermediates. The formation of a dichlorophenol intermediate in triclosan degradation suggested bond-breaking of the ether linkage occurred during the process. Moreover, no chlorinated dibenzo-p-dioxin congener was detected. These findings confirm that the photocatalytic degradation of triclosan is an environmentally friendly process.     

浓磷酸预处理废弃棉织物回收葡萄糖和涤纶的优化

为了实现废弃棉织物的高效资源化利用,采用浓磷酸预处理,将棉纤维转化为葡萄糖,并回收高纯度涤纶.以磷酸浓度、磷酸与原料液固比、预处理温度和时间为研究对象,以涤纶回收纯度、葡萄糖收率为考察指标,采用中心组合设计(CCD),建立响应面模型对预处理工艺参数进行优化.并确定了最佳的浓磷酸预处理工艺条件为:磷酸质量分数85%,液固比15:1,预处理时间7 h,预处理温度50℃.在此条件下涤纶回收纯度可达100%,葡萄糖收率可达79.0%,且实验验证值与模型预测值较为接近,模型精度较高.此外,再生纤维素不经干燥直接酶水解,葡萄糖收率可被进一步提高至83.0%.     

DBP,DOP清洁生产工艺及实施效果

针对增塑剂邻苯二甲酸二丁酯,邻苯二甲二辛酯的生产及废水治理现状,对生产过程的清洁生产审计及是提出清洁生产方案,并进行了实施,实施效果显著,污染物总量减少了８５％产品生产所需原材料有所下降,不仅具有环保效益,同时也有一定的经济效益。     

无机超滤技术和生化处理技术在宝钢冷轧含油废水处理中的应用

冷轧废水处理是轧钢工艺中的难点之一。宝钢 2 0 30冷轧废水处理改造工程 ,首次将生化处理技术引入到冷轧含油废水处理工艺 ,并在工程中采用了无机陶瓷超滤技术 ,从而实现了冷轧废水处理的国产化及国内技术总成     

Species richness in a riparian plant community along the banks of the Xiangxi River,the Three Gorges region

The distribution of vascular plant species richness along an altitudinal gradient and their relationships with environmental variables, including slope, aspect, bank (flooding) height, and river width of the Xiangxi River, Hubei Province, were examined. Total vascular plant species richness changed with elevation: it increased at lower elevations, reached a maximum in the midreaches and decreased thereafter. In particular, tree and herbaceous species richness were related to altitude. Correlation analysis (Kendall's τ) between species richness and environmental variables indicated that the change in species richness in the riparian zone was determined by riparian environmental factors and characteristics of regional vegetation distribution along the altitudinal gradient. The low species richness at lower elevations resulted from seasonal flooding and human activities – agriculture and fuel collection – and the higher species richness in the midreaches reflected transitional zones in natural vegetation types that had had little disturbance. These results on species distribution in the riparian community could be utilized as a reference for restoration efforts to improve water quality of the emerging reservoir resulting from the Three Gorges Hydroelectric Dam project.