不同粒径羟基磷灰石对污染土壤铜镉磷有效性和酶活性的影响

为研究不同粒径羟基磷灰石对重金属污染土壤的修复效果,采用向污染土壤添加常规磷灰石（150 μm）、微米（3 μm）和纳米（40 nm）羟基磷灰石的田间原位试验方法,考察其钝化修复5 a后对土壤铜镉磷有效性和酶活性的影响.结果表明:3种粒径羟基磷灰石均提高了土壤pH,降低了土壤交换性酸和交换性铝的含量,且微米羟基磷灰石处理效果最好.常规磷灰石、微米和纳米羟基磷灰石处理分别使w（离子交换态铜）降低了62.6%、74.3%和70.4%,w（离子交换态镉）降低了15.7%、25.3%和26.7%.3种材料均增加了土壤w（TP）,其中4.61%~17.4%和73.4%~89.8%分别转化为树脂磷和稳定态磷.微米羟基磷灰石处理分别使土壤脲酶活性和微生物量碳含量提高了4.66和0.66倍.研究显示,微米羟基磷灰石更有利于铜和镉由活性态向非活性态转化,增加土壤磷的有效性,提高土壤微生物活性,在我国南方重金属污染红壤区具有较好的应用潜力.      

金铜矿下游农户家养番鸭体内重金属分布特征及其评价

为研究采矿活动及其污染事故对家禽养殖的影响,分别采集了金铜矿下游两岸不同村庄农户家养番鸭10只,分析了鸭肉、鸭肝和鸭血样品中Cu、Hg和As的含量,并对番鸭体内重金属的健康安全进行了评价.结果表明,在相同组织中,Cu含量较Hg和As高.在不同组织中,鸭肝样品中Cu含量最高,平均值为17.20 mg.kg-1,而Hg和As在3个组织间含量无明显差异.金铜矿下游两岸不同村庄农户番鸭样品体内3个组织中Cu、Hg和As的含量均未显示出明显的空间分布规律,表明污染事故及正常的采矿活动未对下游两岸村庄农户家养番鸭样品构成明显影响.所研究番鸭体内3个组织中的Cu、Hg和As的含量都处于正常值范围,且番鸭健康状况未表现出异常.但参照国家食品卫生标准评价结果显示,鸭肝样品中Cu超标率达到100%,最高超标1.74倍,部分鸭肉、鸭血与鸭肝样品中Hg含量也达到较高水平.     

铜胁迫对不同基因型谷子幼苗基因组DNA多态性的影响

采用室内盆栽土培法,以4种基因型谷子(D2-8、安06、黄米、朝谷)为供试材料,研究了不同浓度Cu2+胁迫对谷子幼苗体内可溶性糖、脯氨酸、丙二醛(MDA)含量和基因组DNA多态性的影响.结果表明,经50~400 mg·kg-1Cu2+处理30 d后,4种谷子幼苗体内可溶性糖含量与对照相比呈现先上升后下降的趋势,在50 mg·kg-1时达到最大值.当浓度为200mg·kg-1以上时,4种谷子的可溶性糖含量的平均降幅为对照的32.44%~56.5%.脯氨酸则表现为低含量(≤50 mg·kg-1)的促进和高含量(≥100 mg·kg-1)的抑制效应,MDA含量均有增加且与对照差异显著(P<0.05).Cu2+胁迫下不同基因型谷子幼苗基因组DNA的RAPD图谱发生明显变化,表现为单条或多条RAPD谱带的增加和缺失或者荧光强度的改变,细胞中基因组模板DNA的稳定性下降,DNA多态性变化与Cu2+浓度之间存在剂量-效应关系.不同基因型谷子对Cu2+胁迫的生理和遗传损伤响应存在差异.利用RAPD技术获得的DNA多态性变化可作为检测Cu2+遗传毒性效应的生物标记物.     

温度与pH对生物合成施氏矿物在酸性环境中溶解行为及对Cu2+吸附效果的影响

探析施氏矿物在不同温度、pH下的溶解行为,对其在酸性煤矿废水(ACMD)重金属去除领域的应用具有重要的工程指导意义.本研究通过摇瓶实验,在0.16mol·L-1FeSO4·7H2O,初始pH为2.5的酸性体系中,采用氧化亚铁硫杆菌A.ferrooxidans催化合成施氏矿物.考察了15℃与30℃,pH为2.0$6.0环境条件下矿物的溶解行为,及生物合成施氏矿物对酸性体系Cu2+的吸附去除效果.研究结果表明,经过24h反应,施氏矿物合成体系pH从原始2.50降低至2.18,体系Fe2+氧化完全,27.3%的铁离子参与矿物的合成,矿物分子式可表示为Fe8O8(OH)4.22(SO4)1.89.生物合成施氏矿物在温度为15℃,pH分别为3.2、3.0、2.8、2.6、2.4、2.2与2.0液态体系中振荡72h,矿物溶解率分别为1.92%、3.34%、5.90%、13.09%、28.74%、44.53%与61.46%.在温度为30℃的上述酸度体系中,矿物溶解率在相应时间却达到2.04%、3.98%、8.34%、20.53%、43.50%、96.74%与99.92%.在pH≥3.5的不同温度液态体系中该矿物无溶解迹象.在15℃,pH为6.0、5.0、4.5、4.0与3.5,Cu2+浓度为40mg·g-1的液态体系中,生物合成施氏矿物对Cu2+的吸附量为(50.9±2.2)、(47.3±13.3)、(40.5±4.7)、(31.1±5.0)及(16.9±6.5)mg·g-1.体系酸度一定,施氏矿物在15℃与30℃条件下对Cu2+的吸附效果无显著差异.本研究结果对生物合成施氏矿物在ACMD重金属去除工程应用提供必要的参数支撑.     

高岭土负载纳米Fe/Ni同时去除水中Cu2+和NO3-

工业废水常含有不同污染物如重金属离子和无机阴离子,而如何有效去除复合污染物就成为环境科学前沿研究的挑战性课题.这些污染物因化学性质不同而导致去除机理和途径也不同.本文采用合成高岭土负载纳米双金属Fe/Ni(K-Fe/Ni)同步去除水中Cu2+和NO-3.结果表明K-Fe/Ni能有效去除水中Cu2+和NO-3,但它们的去除效果却会相互受到影响.在Cu2+浓度为200mg·L-1时,NO-3的去除率达到42.5%;而未加入Cu2+时,NO-3的去除率仅有26.9%,说明Cu2+的存在提高了NO-3降解效率.同样,水中NO-3的存在也影响Cu2+的去除(Cu2+去除率从99.7%降到96.5%).但NO-3浓度对去除Cu2+的影响小于Cu2+浓度对NO-3的影响.通过BET比表面积、X射线衍射(XRD)、扫描电镜(SEM)、X射线能量散射(EDS)和X射线光电分析(XPS)对K-Fe/Ni表征的结果显示,反应后K-Fe/Ni的表面存在铁的氧化物、Ni0和被还原的Cu0.基于以上结果,我们发现K-Fe/Ni同步去除水中Cu2+和NO-3的机理是:高岭土负载下的纳米Fe0作为还原剂,在Ni0的催化产氢作用下将Cu2+还原成Cu0并沉积在K-Fe/Ni上而形成纳米Fe/Ni/Cu三金属催化剂,从而加速催化水中NO-3降解.     

Removal of Cu(II) from acidic electroplating effluent by biochars generated from crop straws

The removal efficiency of copper(Cu(Ⅱ)) from an actual acidic electroplating effluent by biochars generated from canola,rice,soybean and peanut straws was investigated.The biochars simultaneously removed Cu(Ⅱ) from the effluent,mainly through the mechanisms of adsorption and precipitation,and neutralized its acidity.The removal efficiency of Cu(Ⅱ) by the biochars followed the order:peanut straw char > soybean straw char > canola straw char > rice straw char a commercial activated carbonaceous material,which is consistent with the alkalinity of the biochars.The pH of the effluent was a key factor determining the removal efficiency of Cu(Ⅱ) by biochars.Raising the initial pH of the effluent enhanced the removal of Cu(Ⅱ) from it.The optimum pyrolysis temperature was 400°C for producing biochar from crop straws for acidic wastewater treatment,and the optimum reaction time was 8 hr.     

Formic acid as an alternative reducing agent for the catalytic nitrate reduction in aqueous media

Formic acid was used for the nitrate reduction as a reductant in the presence of Pd:Cu/γ-alumina catalysts. The surface characteristics of the bimetallic catalyst synthesized by wet impregnation were investigated by SEM, TEM-EDS. The metals were not distributed homogeneously on the surface of catalyst, although the total contents of both metals in particles agreed well with the theoretical values. Formic acid decomposition on the catalyst surface, its influence on solution pH and nitrate removal efficacy was investigated. The best removal of nitrate (50 ppm) was obtained under the condition of 0.75 g/L catalyst with Pd:Cu ratio (4:1) and two fold excess of formic acid. Formic acid decay patterns resembled those of nitrate removal, showing a linear relationship between kf (formic acid decay) and k (nitrate removal). Negligible amount of ammonia was detected, and no nitrite was detected, possibly due to buffering effect of bicarbonate that is in situ produced by the decomposition of formic acid, and due to the sustained release of H2 gas.     

Adsorption of Cr(Ⅲ) from acidic solutions by crop straw derived biochars

Cr（Ⅲ） adsorption by biochars generated from peanut, soybean, canola and rice straws is investigated with batch methods. Adsorption of Cr（Ⅲ） increased as pH rose from 2.5 to 5.0. Adsorption of Cr（Ⅲ） led to peak position shifts in the FFIR-PAS spectra of the biochars and made zeta potential values less negative, suggesting the formation of surface complexes between Cr^3＋ and functional groups on the biochars. The adsorption capacity of Cr（Ⅲ） followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char, which was consistent with the content of acidic functional groups on the biochars. The increase in Cr^3＋ hydrolysis as the pH rose was one of the main reasons for the increased adsorption of Cr（Ⅲ） by the biochars at higher pH values. Cr（llI） can be adsorbed by the biochars through electrostatic attraction between negative surfaces and Cr^3＋, but the relative contribution of electrostatic adsorption was less than 5%. Therefore, Cr（Ⅲ） was mainly adsorbed by the biochars through specific adsorption. The Langumir and Freundlich equations fitted the adsorption isotherms well and can therefore be used to describe the adsorption behavior of Cr（Ⅲ） by the crop straw biochars. The crop straw biochars have great adsorption capacities for Cr（Ⅲ） under acidic conditions and can be used as adsorbents to remove Cr（Ⅲ） from acidic wastewaters.     

顶空／气相色谱-质谱法测定水中四乙基铅

建立了顶空,气相色谱-质谱法测定水中四乙基铅方法。水样中的四乙基铅直接顶空进样,质谱分析。实验结果表明,在0．10-5．00μg几范围内线性关系良好,方法检出限为0．02μg/L,得到了良好的分离效果与较高的灵敏度和精密度。方法简便快捷,能达到《生活饮用水卫生规范》（GB/T5750．8—2006）中规定的要求。     

铅酸蓄电池生命周期评价

铅酸蓄电池是世界上产量最大、用途最广的一种二次电池。铅酸蓄电池生命周期过程中每一个环节都有可能对环境带来不利影响,评估从生产到废弃处理关键过程中对环境的影响,可以为制定有效的管理政策提供科研支撑。目前,尚缺乏针对我国特色的铅酸蓄电池行业全生命周期评价的研究,造成此行业的污染防治无据可依。因此,本研究针对铅酸蓄电池的生命周期进行评价,通过设定研究目的与范围、收集数据与分析清单、获得影响评价和解释结果,研究了铅酸蓄电池对环境的影响,结果表明铅酸蓄电池在生产环节的板栅浇铸过程和废弃处理环节的脱硫过程应属于管理中着重控制的部分。