电镀污泥的热处理特性以及对金属回收的影响

焙烧-酸浸法可有效回收电镀污泥中的有价金属,而污泥的热处理特性是决定能否采用焙烧预处理的重要因素。研究了氧化焙烧和还原焙烧对污泥成分和金属浸出性的影响,并对焙烧前后的污泥进行了金属形态分析和X射线衍射(XRD)分析。结果表明,焙烧预处理实现了污泥减量和金属富集;ES1经氧化焙烧后金属浸出率接近原泥,Cu的浸出率达99%;ES2的还原焙烧效果优于氧化焙烧,特别是Cu的浸出率超过97%,XRD分析发现,还原焙烧过程中金属Cu被还原为铁铜合金;2种焙烧均造成了ES3中目标金属Ni的浸出率的降低;金属浸出性的下降与残渣态的形成有关。     

Low uptakes of Cd,Cu, and Zn in Dugesia japonica,a freshwater planarian with higher tolerance to metals

Although a freshwater planarian is proposed as a potential model for studying toxicities of environmental pollutants, they are less sensitive to metal exposures, compared to other freshwater invertebrates. We hypothesised that the metal uptake is low in treated planarians, which may lead to their higher tolerance to metals. The acute toxicities of Cu and Zn to Dugesia japonica were determined. The 24- and 48-h median lethal concentrations were 4.50 and 3.46?mg?L^?1, respectively, for Cu, and 41.97 and 37.79?mg?L^?1, respectively, for Zn. Accordingly, combining with the data on Cd in our previous study, higher tolerance of planarians to metals was revealed. Also, tissue levels of Cd, Cu, and Zn in treated D. japonica were determined, and their dissolved uptake rate constants (k₁) were calculated. Results showed that bioaccumulations of these metals in D. japonica were, indeed, lower than that in other freshwater invertebrates having higher susceptibilities to these metals.     

离子液体对废旧印刷线路板中铜、锌、铅的浸出规律

以离子液体1-丁基磺酸-3-甲基咪唑三氟甲烷磺酸盐([BSO_3HMIm]OTf)为浸出剂,初步研究了WPCBs浸铜过程中锌和铅浸出率的影响因素。实验结果表明:铜、锌的浸出率随着WPCBs粒径的减小、H_2O_2溶液加入量的增大而增大,铜的浸出率随浸出温度的升高先增大后减小,锌的浸出率受浸出温度影响不大;铅的浸出率受5种因素影响不大,且总体处于较低水平。在WPCBs粒径为0.100~0.250 mm、离子液体加入量为60.0%(φ)、H_2O_2溶液加入量为7.5%(φ)、固液比为1∶15、浸出温度为50℃的条件下,铜、锌、铅的浸出率分别为99.84%,93.25%,22.46%。     

电解铝企业阳极残渣、阳极残极浸出毒性鉴别及管理建议

对电解铝企业产生的阳极残渣、阳极残极浸出毒性进行了鉴别。鉴别结果表明：电解铝企业产生阳极残渣浸出液中氟化物（不含氟化钙）平均质量浓度为140 mg／L，最高达244 mg／L，且超标试样数达到《危险废物鉴别标准浸出毒性鉴别》中相应规定，鉴别该废物属于危险废物，应按照危险废物进行管理；阳极残极浸出液中氟化物（不含氟化钙）平均质量浓度为74 mg／L，无超标试样数，该废物不属于具有氟化物浸出毒性的固体废物，建议仍按一般固体废物进行管理。     

甲苯对UASB反应器中溶解性微生物产物的影响

以乙酸钠为外加碳源,考察了UASB反应器内甲苯对可溶性微生物产物（SMP）的影响。实验结果表明：低质量浓度（20~70 mg/L）的甲苯对微生物有刺激作用,使得污泥增殖速率变小,SMP的质量浓度也逐渐减少,经过一段时间的驯化后,系统COD和TOC的去除率分别达到93%和94%以上,下降趋势较小；较高质量浓度（70~200 mg/L）的甲苯对微生物有抑制作用,污泥活性下降,反应器运行状况开始恶化,SMP的质量浓度也逐渐增大,经过一段时间的驯化后,系统COD和TOC的去除率分别维持在81%和83%以上；当甲苯质量浓度超过200 mg/L时,表现为污泥活性严重下降,对COD的去除效果极差。     

赤霉酸暴露对SD大鼠青春期发育的影响

赤霉酸是目前国内外使用极其广泛的一种植物生长调节剂,但是针对其发育毒性的数据依然较少。本文探讨了赤霉酸暴露对SD大鼠青春期发育的影响。参考国内外环境内分泌干扰物危害的评价方法,将144只初断乳SD大鼠按体重随机分为4组,分别为对照组和1、10、100 mg·kg-1bw剂量组,采用经口灌胃方式对雄鼠连续染毒28 d,雌鼠连续染毒21 d。暴露结束后检测大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、血清生化指标、脏器系数及组织病理学的变化。研究结果表明,与对照组相比,仅10和100 mg·kg-1bw剂量组雄鼠的肌酐水平显著升高(P<0.01),100 mg·kg-1bw剂量组雌鼠谷丙转氨酶水平有显著升高(P<0.01)。而与对照组相比,所有剂量组均未观察到大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、脏器系数等指标有显著性差异的改变(P>0.05),组织病理学结果亦显示大鼠重要器官无损害性改变。因此,在本试验给予的剂量范围内赤霉酸染毒不会对SD大鼠青春期发育产生显著影响。     

双酚A及其类似物对斑马鱼胚胎及幼鱼的毒性效应

为探讨双酚A及其类似物对鱼类早期生长发育的毒性效应,研究了双酚A及其7种类似物对斑马鱼胚胎及仔鱼的毒性效应。通过对胚胎的孵化率、心率、仔鱼体长等指标进行测定分析,结果显示:(1)双酚A及其7种类似物都可使斑马鱼胚胎出现心包水肿、卵黄囊肿、脊柱弯曲和尾部弯曲等症状。(2)综合考虑斑马鱼78 hpf胚胎心率、120 hpf胚胎孵化率及7 dpf仔鱼体长抑制率等指标,8种受试物中双酚P(BPP)的毒性最大,其次是双酚AP(BPAP)、双酚AF(BPAF)、双酚Z(BPZ),然后是双酚A(BPA)、双酚B(BPB)、双酚F(BPF),双酚S(BPS)的毒性最小,每种受试物的浓度与受精卵的孵化率、仔鱼心率呈明显负相关关系,与体长抑制率呈明显正相关关系。8种受试物毒性与辛醇-水分配系数(log K_(OW))呈正相关关系,log K_(OW)越大毒性则越大。     

土壤Cd污染对跳虫Folsomia candida的生态毒性

采矿及冶炼等行为造成了严重的土壤重金属污染,其中Cd污染及其带来的健康风险近年来引起人们的高度重视。利用弹尾目跳虫开展土壤Cd污染的生态毒理研究,对Cd污染土壤的生态风险评价具有重要意义。本研究将跳虫Folsomia candida(F.candida)暴露在不同Cd浓度污染的人工土壤中,利用跳虫存活数量、繁殖数量及回避行为实验来评价重金属Cd污染对跳虫的生态毒性。结果表明,Cd对F.candida的急性毒性LC50值为2 086.93 mg·kg~(-1),慢性毒性的繁殖抑制(28 d)EC50值为224.95 mg·kg~(-1)。此外,Cd对跳虫回避行为影响的EC50(48 h)为721.26 mg·kg~(-1)。可以看出,慢性毒性的EC50值与Cd对回避行为影响的EC50值近似,但远低于急性毒性LC50值。因此,跳虫F.candida的回避行为和繁殖率对Cd污染土壤有较高的灵敏度,可用来表征土壤中Cd的生态毒性。     

Advantages and risks of using steel slag in preparing composts from raw organic waste

It had been reported that iron and manganese oxides in steel slag enhanced the production of humic acid (HA) from low-molecular-weight compounds, such as phenolic acids, amino acids, and saccharides. In the present study, this function of steel slag was applied to the composting of raw organic wastes (ROWs). The degree of humification of HAs is an important factor in evaluating compost quality. Thus, HAs were extracted from the prepared composts and the humification parameters were determined, in terms of elemental compositions, acidic functional group contents, molecular weights, spectroscopic parameters from UV–vis absorption and ¹³C NMR spectra. The timing for adding steel slag affected the degree of humification of HAs in the composts. The weight average molecular weight of a HA when slag was added initially (29 kDa) was significantly higher than when slag was added after elevating the temperature of the compost pile (17–18 kDa). These results show that ROWs are decomposed to low-molecular-weight compounds after the pile temperature is elevated and the presence of slag enhances the polycondensation of these compounds to produce HAs with a higher degree of humification. Because the slag used in the present study contained several-tens ng g^?1 to several μg g^?1 of toxic elements (B, Cu, Cr, and Zn), leaching tests for these elements from the prepared composts were carried out. Levels for leaching boron from composts prepared by adding slag (0.2–0.4 mg L^?1) were obviously higher than the corresponding levels without slag (0.05 mg L^?1).     

海洋中微塑料的环境行为和生态影响

微塑料一般指直径小于5 mm的微小型塑料颗粒或碎片,海洋中常见的微塑料类型主要包括聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯等。由于形状、颜色多变,分子量大,结构稳定,粒径范围与浮游植物相近,海洋中的微塑料很容易对浮游植物、浮游动物和其他海洋动物等产生影响。微塑料还可以为病毒、细菌提供附着载体,影响浮游植物分布,进入海洋生物消化道或进一步转移到组织中对机体产生毒性效应,甚至通过捕食作用沿食物链传递,对高等动物及人类健康造成威胁。此外,微塑料可以作为海水中痕量化学物质的吸附载体,对生物产生联合毒性。根据目前对微塑料的研究进展情况,未来应加强对海洋微塑料分离、鉴定技术的研发以及海洋微塑料的生物毒性效应和生物传递效应机制等问题的研究。