固定化细胞技术处理含酚废水的研究

固定化细胞技术的关键是所用载体材料的性能。本文力求寻找一种价格低、寿命长、效率高的载体。通过同一菌种在固定状态和游离状态降解含酚废水的实验对比，证明红砖碎粒是一种优良的载体材料。利用正交实验，确定了该菌种在固定时的最佳运行条件。并对游离细胞和固定细胞降解苯酚的过程进行了动力学分析。结果表明，在两种情况下，该菌种降解苯酚的过程均符合Ｍｏｎｏｄ模型。     

Y型与ZSM-5型分子筛吸附VOCs性能的对比

从疏水性较好的分子筛中筛选出2类吸附性能优良的分子筛,通过实验考察其对VOCs的吸附量、脱附量、吸附穿透曲线、脱附活化能等,评价其对VOCs的吸附脱附性能;评估了所选分子筛经多次吸附再生后的性能稳定性,建立了一套分子筛工业应用性能指标体系。结果表明：Y型分子筛性能优于ZSM-5型分子筛;同种分子筛比表面积及孔径越大,单位质量能吸附的VOCs量越多;在甲苯/乙酸丁酯的竞争吸附体系中,Y型分子筛及ZSM-5型对甲苯的吸附量较单组分情况下分别下降了50.1%、40.1%,而对乙酸丁酯的吸附量分别增加了189%、102%;甲苯在Y型分子筛上的脱附活化能为76.7 kJ·mol⁻¹,在ZSM-5分子筛上的脱附活化能为64.7 kJ·mol⁻¹;Y型分子筛和ZSM-5型分子筛均具有较好的循环使用性,吸附性能稳定;Yoon-Nelson模型能较好地拟合分子筛吸附穿透曲线,拟合系数在0.97以上。     

Computerised Decision Support Systems for the management of freshwater radioecological emergencies: assessment of the state-of-the-art with respect to the experiences and needs of end-users

Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS “integration” became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS.     

河北廊坊降水对PM2.5质量浓度的湿清除作用

采用2013～2017年廊坊市区逐时PM2.5质量浓度监测数据及对应气象资料,分析降水对PM2.5质量浓度的影响。研究表明,有降水时的PM2.5质量浓度,年均值比无降水时偏低21.7%～47.1%,月均值在2月、4～11月低于无降水,一日内逐时次值均低于无降水;降水对PM2.5质量浓度的湿清除受降水前其浓度大小与降水量的共同影响,降水前PM2.5质量浓度45μg/m3时,正清除量明显增加到21μg/m3以上,春、夏、秋、冬四季降水前PM2.5质量浓度(μg/m3)分别为31.8、≥30.0、≥40.0、≥156.8时,正清除概率大于71%,降水量超过5 mm以后,正清除占比达负清除的3倍以上;降水强度对PM2.5质量浓度的清除作用在冬季表现不明显,而春季、夏季、秋季当降水强度(mm/h)分别0.7、1.9和0.6时正清除概率达76.9%、94.1%和87.5%。     

Influence of temperature on the heavy metals accumulation of five vegetable species in semiarid area of northwest China

The aim of the present study was to investigate the possible effects of temperature on cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) accumulation in five vegetable species collected at different sites (Shuichuan, Beiwan, Dongwan and Wufe) in northwest China. The meteorological data of air and soil temperatures were recorded daily during the period from sowing to harvest for the five vegetables. The air and soil temperatures affected the capacity of pumpkin, cabbage, brassica napus and Chinese cabbage to accumulate Zn, Cd, Cu and Pb. Principal component analysis showed that temperature, photosynthetic and physiological factors all contributed to the soil–plant transfer properties of DTPA-extractable heavy metals. Temperature played a more important role in Cd, Pb, Cu and Zn accumulation in four vegetables in this semiarid area. However, the enormous surface area of spinach was likely to elevate heavy metal loads owing to atmospheric deposits. For most vegetables studied, there was a striking dissimilarity in the uptake and translocation ability of Cd, Zn and Cu in soil, but similar accumulation to translocation for Pb in soil.     

河北省廊坊市大气污染扩散气象条件影响分析

对廊坊市1960—2012年气象资料和2012—2013年廊坊市空气质量监测资料进行了统计分析,结果发现:由于风速偏小,低层逆温日数多,中性及稳定天气偏多等气象条件,加之城镇化的发展使得廊坊市区大气污染扩散气象条件更加不利。雨雪对空气有净化作用,尤其是降雨的净化作用更加明显。风速、风向对空气中不同的污染物影响不同,平均风速大于5 m/s或瞬时风速大于8 m/s是造成廊坊PM10迅速增大的临界指标。针对廊坊城区大气污染的成因进行了分析。     

河西走廊东部沙尘日变化特征及其与气象因子的关系

沙尘天气是河西走廊东部多发的灾害天气之一.为提高河西走廊东部沙尘天气的预测、预报、预警水平,更好地预防沙尘灾害和沙尘天气对空气质量的污染.利用河西走廊东部5个气象站1960-2016年逐日沙尘（包括浮尘、扬沙及沙尘暴）资料和四季平均气温、最高气温、最低气温、平均风速、大风日、蒸发量、降水量、相对湿度等资料,运用统计学方法分析了河西走廊东部各强度沙尘日的时空分布特征以及沙尘日与气象因子的相关性.结果表明:受海拔、地形地貌以及天气系统等影响,各强度沙尘日（除浮尘外）由东北向西南呈递减趋势.年代、年各强度沙尘日呈显著减少趋势,沙尘暴、扬沙、浮尘递减率分别为-2.436、-5.277、-5.719 d/（10 a）,气候趋势系数均通过了α=0.01的显著性水平检验.年沙尘日的时间序列均存在着6~8 a的准周期变化.各强度沙尘日均为春季最多,秋季最少,且各季节沙尘日均呈显著减少趋势,递减率为春季>夏季>冬季>秋季,气候趋势系数均通过了α=0.01的显著性水平检验.各强度沙尘日月变化比较一致,高峰值出现在4月,低谷值出现在9月.气象因子对沙尘天气有一定的影响,同一季节气象因子对各强度沙尘日的影响相对一致,但不同的季节气象因子对各强度沙尘日的影响不一致.热力因子和动力因子是影响沙尘天气的主导因子,水分因子的影响较弱.研究显示,气候变暖、冷空气活动频次和强度减弱是沙尘日减少的主要原因之一,大气环流的季节性转变是沙尘天气季节性变化的主要原因.