碳酸化对不同碱度飞灰中重金属的长期影响

通过对不同地区生活垃圾焚烧飞灰进行碳酸化处理,采用XRF,SEM以及XRD分析飞灰理化特性,通过pH值测定、重金属浸出实验以及重金属形态分析探究CO₂对不同焚烧飞灰中超标重金属Zn、Pb、Cd的长期影响研究.结果表明,由于焚烧过程中烟气排放限值降低需喷入大量氢氧化钙等脱酸剂,导致焚烧飞灰呈现不同碱度特性.根据醋酸缓冲溶液法浸出实验后的飞灰浸出液pH值,将飞灰分为“酸灰”与“碱灰”,并对两类飞灰进行长期碳酸化实验.对比碳酸化前后飞灰中重金属的浸出毒性,“酸灰”中重金属浸出毒性远大于“碱灰”,但是碳酸化处置后“酸灰”中重金属Zn、Cd的浸出浓度分别降低10%~18%和9%~30%;“碱灰”中重金属Zn和Cd的浸出浓度显著增大,且浸出浓度最大超过《生活垃圾填埋场污染控制标准》的1.46与63.2倍;碳酸化对“酸灰”与“碱灰”中的两性重金属Pb的浸出不具有规律性,但总体而言,碳酸化对“碱灰”中重金属Pb的影响更大.最后通过BCR连续分级提取法分析碳酸化前后飞灰中重金属形态的变化规律,碳酸化后,“酸灰”中重金属Zn、Cd的浸出浓度受到T4赋存占比增加的影响呈下降趋势,但部分样品中T1赋存占比有增加现象,说明此类重金属仍存在浸出风险,而“碱灰”碳酸化后重金属Zn、Cd的浸出浓度受到T1赋存占比增加的影响呈增加趋势.因此在填埋处置前应重点关注不同碱度飞灰中的重金属浸出特性,为飞灰长期稳定填埋提供保障.     

Dynamics of Steppe Vegetation under the Effect of Grazing by Different Farm Animals

The process of steppe pasture digression resulting from grazing by different farm animals was studied by the transect method. Sheep, cattle, and horse pastures under similar grazing loads markedly differed in the dynamics of steppe vegetation. The most critical changes in plant communities occurred in sheep pastures, whereas the state of plant communities in horse pastures was good.     

浅议清洁生产对企业环境管理的作用

本文重点论述了清洁生产对企业环境管理的作用,指出清洁生产是深化企业环境管理方式的助推剂。     

北京某区域儿童夏季PM2.5的污染特征及分析

近年来,随着社会和经济的不断发展,人们对室内外空气质量的重视程度也不断提高。室内外空气质量尤其是细颗粒物污染与人群健康密切相关。北京市大气细颗粒物污染形势十分严峻,因此,相关研究也成为国内外研究的热点和难点问题。本文对北京市某区域年龄在9～11岁之间的38名健康儿童人群活动场所夏季PM2.5的污染特征作了研究评价。结果表明,运用室内外环境监测与问卷调查法相结合的研究方法,儿童人员夏季PM2.5室内外浓度呈现明显的时间、空间变化特征,并受到气象因素及室内外源排放的共同影响。     

Accumulation and elimination of iron oxide nanomaterials in zebrafish (Danio rerio) upon chronic aqueous exposure

A 52-day continuous semi-static waterborne exposure (test media renewed daily) regimen was employed to investigate the accumulation and elimination profiles of two iron oxide nanomaterials (nano-Fe₂O₃ and nano-Fe₃O₄) in zebrafish (Danio rerio). Adult zebrafish were exposed to nanomaterial suspensions with initial concentrations of 4.0 and 10.0 mg/L for 28 days and then were moved to clean water for 24 days to perform the elimination experiment. Fe content was measured in fish body and feces to provide data on accumulation and elimination of the two iron oxide nanomaterials in zebrafish. The experiment revealed that: (1) high accumulation of nano-Fe₂O₃ and nano-Fe₃O₄ were found in zebrafish, with maximum Fe contents, respectively, of 1.32 and 1.25 mg/g for 4.0 mg/L treatment groups and 1.15 and 0.90 mg/g for 10.0 mg/L treatment groups; (2) accumulated nanoparticles in zebrafish can be eliminated efficiently (the decrease of body burden of Fe conforms to a first-order decay equation) when fish were moved to nanoparticle-free water, and the elimination rates ranged from 86% to 100% by 24 days post-exposure; and (3) according to analysis of Fe content in fish excrement in the elimination phase, iron oxide nanomaterials may be adsorbed via the gastrointestinal tract, and stored for more than 12 days.     

昆明城市生活垃圾处理产业发展的SWOT分析研究

随着城市化进程的深入,生活垃圾问题日益突出,城市生活垃圾处理产业的发展是解决“垃圾围城”困境的有效途径.昆明城市生活垃圾处理产业处于发展阶段,运用态势分析法(SWOT),系统地对昆明城市生活垃圾处理产业发展的优势、劣势、所存在的机会和威胁进行分析,并提出相应发展对策,包括完善生活垃圾处理.产业的经济激励机制;采用多种项目融资模式进行生活垃圾产业建设融资;加快静脉产业园区建设发展;打造再生资源回收利用的龙头企业;积极控制生活垃圾源头;建立垃圾排放权交易等.     

磁性Fe_3O_4/石墨烯异质结固定漆酶特性及其对水中双酚A的降解研究

以磁性石墨烯为载体制备了磁性石墨烯固定化漆酶,考察了固定化漆酶的酶学特性及其对双酚A(BPA)的降解效能。结果表明,氧化石墨烯的比表面积高达726.34 m2·g-1,与游离漆酶相比,经过石墨烯固定化后漆酶对酸的适应能力、耐热性和贮存稳定性均有所提高,p H值2.0~4.0范围内固定化漆酶活性较为稳定;加入变性剂尿素(1 mol·L-1)后,固定化漆酶的相对活性为87%,游离漆酶相对活性仅为63.02%,固定化导致抗变性剂能力增强。固定化漆酶和游离漆酶活性分别在45和40℃时达到最大值。与游离漆酶相比,固定化漆酶最佳反应温度升高了5℃,且在50℃时,固定化漆酶的相对活性依然保持在95.11%;25℃,p H值4.0条件下保存10 d,固定化漆酶活性为最初活性的82.57%;固定化漆酶具有良好的重复利用性,重复利用10次后,漆酶活性仍为最初活性的82.01%。固定化酶的米氏常数Km为5.38×10-4 mol·L-1,较游离酶的大,说明固定化酶与底物的亲和力比游离酶小。磁性石墨烯固定化漆酶具有良好的吸附能力,可吸附-催化氧化水中的BPA,且石墨烯良好的吸附作用促进了催化反应,水中BPA质量浓度为15 mg·L-1时,经过18 h反应,BPA的去除率能达到82.14%左右。本研究的结果为石墨烯新型材料固定化漆酶及其应用提供了参考。     

Energy metabolism and thermoregulation in reindeer during early postnatal development

The interrelations of body weight, energy metabolism, and physiological parameters in the early postnatal development of reindeer are analyzed. It is shown that the dependence of energy expenditure at rest and oxygen utilization coefficient on body weight is described by a parabolic equation of the second order. At high ambient temperatures during the summer season, energy metabolism in the young decreases, heat emission by respiration increases, and the temperature homeostasis is disturbed.