HCHs and DDTs in sediment-dwelling animals from the Yangtze Estuary, China

HCHs and DDTs in sediment-dwelling animals including mollusks and crabs from the Yangtze Estuary were determined by GC-ECD. Levels of t-HCH were in the range of 1.2-5.5 ng g(-1) and averaged 3.5 ng g(-1) in mollusks, while t-DDT concentrations ranged from 26.0 to 68.8 ng g(-1), with a mean of 34.5 ng g(-1). In crabs t-HCH concentrations varied from 2.0 to 25.7 ng g(-1) and averaged 13.8 ng g(-1), whereas the concentrations of t-DDT were in the range of 1.5-24.8 ng g(-1) with a mean value of 5.9 ng g(-1). The HCHs and DDTs levels depend on geographical position and sources, showing the high levels at fresh water area in the estuary, such as XP, CM and LHK sites, and lower at brackish water area, such as FX site, and little difference between species. Results also indicate there was no significant relationship between t-HCH (t-DDT) concentrations and lipid contents both in mollusks and crabs because of non-equilibrium state under a specific estuarine dynamics; smaller individuals accumulated more HCHs and DDTs than larger individuals of mollusks at LHK site, showing different uptake rate for these pesticides; moreover, HCHs and DDTs levels were lower in female crab bodies than male crab bodies suggesting that the release of spawning. BSAFs (Biota- Sediment Accumulation Factors) from sediment-dwelling animals for HCHs and DDTs show a significant "one high with two low" and "one low with two high" effect in the Yangtze Estuary.     

混凝-生物接触氧化法处理城市污水的研究

采用混凝-生物接触氧化法处理生活小区废水,考察了不同混凝剂用量对COD、NH4-N、SS、TP的去除效果,同时研究了生物接触氧化法对COD、NH4-N等的去除以及耐冲击负荷能力.结果表明,随混凝剂用量的增加,COD、SS、TP的去除率随之增加,生物接触氧化法具有较高的抗冲击负荷能力,最大NH4-N去除负荷达到0.55 kg/(m3·d),最大有机去除负荷达到4.32 kg/(m3·d)     

L-半胱氨酸改性甲壳素处理含铅、镉工业废水

研究了L 半胱氨酸改性甲壳素作为吸附剂对Pb2 + 、Cd2 + 的动态吸附性能 ,同时考察了流速、溶液中离子的含量、吸附剂的相对用量等因素对吸附效果的影响 ,以及洗脱液的种类和酸度、洗脱速度、洗脱液体积等因素对解吸率的影响。结果表明 ,用该吸附剂填装的吸附柱对含Pb2 + 、Cd2 + 工业废水直接进行处理 ,处理后的水达到了排放标准。     

Selective leaching of valuable metals from waste printed circuit boards

This study was carried out to recover valuable metals from the printed circuit boards (PCBs) of waste computers. PCB samples were crushed to smaller than 1 mm by a shredder and initially separated into 30% conducting and 70% nonconducting materials by an electrostatic separator. The conducting materials, which contained the valuable metals, were then used as the feed material for magnetic separation, where it was found that 42% of the conducting materials were magnetic and 58% were nonmagnetic. Leaching of the nonmagnetic component using 2 M H2SO4 and 0.2 M H2O2 at 85 degrees C for 12 hr resulted in greater than 95% extraction of Cu, Fe, Zn, Ni, and Al. Au and Ag were extracted at 40 degrees C with a leaching solution of 0.2 M (NH4)2S2O3, 0.02 M CuSO4, and 0.4 M NH4OH, which resulted in recovery of more than 95% of the Au within 48 hr and 100% of the Ag within 24 hr. The residues were next reacted with a 2 M NaCl solution to leach out Pb, which took place within 2 hr at room temperature.     

高级氧化法脱除PVA浆料的清洁生产新工艺研究

为了研究高级氧化法脱除聚乙烯醇（PVA）浆料清洁生产新工艺的可行性，研究了3种高级氧化法UV／H2O2、UV／TiO2、Nation-Fe^2＋／H2O2对含PVA溶液的氧化降解，其降解效果依次为iUV／H2O2〉Nation-Fe^2＋／H2O2〉UV／TiO2。对于UV／H2O2法，PVA降解速率与H2O2的初始浓度成正相关，且H2O2浓度为2．95mmol／L时14min内就能使PVA的去除率达到98％；pH和温度对PVA的氧化降解效果影响不明显。在此基础上，对建立在高级氧化法基础上的退浆新工艺进行了探讨，结果表明，在65℃和75℃下，高级氧化法条件下的纯棉织物PVA退浆率分别达到70．16％和95．65％；该法不仅可以促进PVA从纯棉织物上的脱附，而且可以达到对PVA的较高降解效果，使得所排退浆废水的生化处理难度明显降低。     

Occurrence,sorption, and transformation of free and conjugated natural steroid estrogens in the environment

Environmental Science and Pollution Research - Natural steroid estrogens (NSEs), including free estrogens (FEs) and conjugated estrogens (CEs), are of emerging concern globally among public and...     

Characteristic and mechanism of sorption and desorption of benzene on humic acid

Environmental Science and Pollution Research - The sorption/desorption behaviors of benzene, toluene, ethylbenzene, and xylene (BTEX) on soil organic matter (SOM) have a significant influence on...     

The associations of air pollution exposure during pregnancy with fetal growth and anthropometric measurements at birth: a systematic review and meta-analysis

Environmental Science and Pollution Research - Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air...     

蒸发塔技术用于脱硫废水的处理

脱硫废水水质复杂、含有重金属,处理难度很大,为此开发了一种新型的脱硫废水处理技术——蒸发塔技术,可以实现脱硫废水的零排放。在实验室搭建了小型蒸发塔实验台,对脱硫废水的蒸发特性、热量衡算进行了研究。研究表明：导流板角度一定的情况下,脱硫废水主蒸发区在塔体中心位置,随着脱硫废水处理量的增加,主蒸发区域向塔壁和塔体下部偏移;导流板角度减小,高温区下移;雾矩受给液量和雾化器转速的双重影响,给液量越大,雾矩越大,转速越大,雾矩越小;塔径一定的条件下,适当调节进风量和导流板角度可增加脱硫废水的处理量;模拟计算表明,蒸发系统抽取热烟气量较少,不会对电厂热系统产生明显影响。     

固体废弃物轮胎的热解技术

综述了国内外对废轮胎的处理状况，并详细地讨论了废轮胎热解技术的发展、分类以及典型工艺流程。热解技术主要包括油化技术、气化技术和炭化技术三种，并可制得衍生油、燃料气、碳黑等产品。分析了废轮胎热解工艺存在的问题，指出了如何开发环境友好的集成工艺是废轮胎热解工艺的发展方向。