基于石墨烯构建的电化学传感器在环境监测中的应用

综述了基于石墨烯构建的电化学传感器在重金属、有毒气体、农药残留、酚类有机污染物等对环境造成一定危害的物质检测中的应用,并展望了石墨烯电化学传感器在环境监测领域中的发展。     

污水污泥裂解及其性能的研究

以碘吸附值为裂解残渣吸附性能的指标，通过单因素实验和正交实验，确定了制备裂解残渣的最佳工艺条件，并对残渣的表面元素组成、孔结构组成、晶相组成和吸附性能等性质进行了表征。结果显示：以浓度均为5 mol/L的ZnCl₂和H₂SO₄作活化剂、复配比2∶1、活化温度600℃、活化时间1 h、固液比1∶2.5，制得的裂解残渣酸洗后碘值平均值可达892.8 mg/g；用制备的裂解残渣对苯酚废水进行处理，室温下振荡5 min，苯酚去除率即可达到87.9%，且符合Langmuir吸附等温线方程和Freundlich吸附等温线方程。     

铬渣秸秆共热解产物铬稳定性研究

生物质铬渣共热解工艺是新型的铬渣处理工艺,该工艺能有效地将铬渣中的Cr(Ⅵ)还原为Cr(Ⅲ).而由于共热解产物总铬含量较高,因此考察了铬渣与秸秆共热解过程中铬稳定性.通过考察共热解产物成分及形态分析、pH影响实验、淋洗实验及长期稳定性实验,对共热解铬渣的铬环境安全性进行评估.结果表明:(1)共热解温度对铬渣形态有较大影响,可交换态及碳酸盐结合态铬含量随共热解温度升高而逐渐降低,800℃时候可交换态铬降至＜0.1％(质量分数,下同),碳酸盐结合态铬为1.2％;共热解后最稳定的残渣态铬含量随共热解温度升高而逐渐升高.(2)当pH＞7时,两种共热解产物总铬溶出量极低,基本都小于6mg/kg;当pH≤7时,总铬的溶出量显著增加,最高超过500 mg/kg.但由于解毒铬渣的酸中和能力极强,因此铬释放风险较低.(3)共热解产物的总铬累积溶出量极低,根据拟合结果计算出其100年填埋时间的总铬溶出量不超过1.3 mg/kg.长期稳定性实验表明,自然堆置过程中共热解产物的Cr(Ⅵ)含量逐渐降低.     

铬渣的热解无害化处理

采用热解工艺无害化处理铬渣,探讨了稻秆在铬渣无害化处理中的作用.研究了热解温度、稻秆与铬渣质量比、铬渣粒径及保温时间对铬渣热解无害化处理的影响,并分析了热解前后热解产物中铬元素形态的变化.结果表明,热解工艺能有效地将铬渣中Cr(Ⅵ)还原,稻秆热解过程中产生的气相挥发分对Cr(Ⅵ)的还原起核心作用.较为适宜的热解条件:热解温度为400 ℃,稻秆与铬渣质量比为0.10,铬渣粒径<2 000 μm,保温时间为10 min.在该热解条件处理下,热解产物中的Cr(Ⅵ)质量浓度为121 mg/kg,低于热解前铬渣中的Cr(Ⅵ)(3 400 mg/kg).热解后,可交换态及碳酸盐结合态铬含量降低,大部分铬转化成了稳定的有机结合态和残渣态,极大地降低了铬渣的危害.第一作者:张大磊,男,1982生,博士研究生,研究方向为固体废弃物热处理.     

Limitations in the determination of maximum residue limits and highest residues of pesticides: Part I

The pesticide usages are controlled by comparing residue concentrations in treated commodities to legally permitted maximum levels (MRLs) determined based on supervised trials designed to reflect likely maximum residues occurring in practice following authorised use. The number of trials available may significantly affect the accuracy of estimated maximum residues. We conducted a study with synthetic lognormal distributions with mean of 1 and standard deviations of 0.8 and 1.0, which reflect the residue distributions observed in practice. The likely residues in samples were modelled by drawing random samples of size 3, 5, 10 and 25 from the synthetic populations. The results indicate that the estimations of highest residues (HR), used for calculation of short-term intake, and the MRLs, serving as legal limits, are very uncertain based on 3–5 trials indicated by the calculated HR_0.975/HR_0.025 and MRL_0.975/MRL_0.025 ratios of 12 and 9, and 13 and 10, respectively, which question the suitability of such trials for the intended purpose. As the 95% range of HR and MRL rapidly decreases with number of trials, ideally ≥15 but minimum 6–8 trials should be used for estimation of HR and MRL according to the current typical practice of Codex Alimentarius.     

电解锰渣中锰的浸出条件及特征

采用水洗-酸解法回收电解锰渣中锰,探讨了清水量、酸量以及温度在不同阶段对锰浸(洗)出条件的影响,分析了回收锰的主要因素及浸出特征。实验结果表明,50 g电解锰渣经m渣∶m水=1∶10的清水水洗后,采用10%的硫酸在70℃的水浴温度下酸解2 h,Mn2+浸出量为1.673 g,回收率达到97.3%,而温度和酸度对锰离子的浸出影响明显,酸度调控可有效分离酸浸锰液中金属成分,为减少电解锰渣环境污染的同时,实现电解锰渣资源化利用。     

不同种植方式蔬菜中农药残留的差异及污染控制研究

采集了陕西地区不同种植方式的瓜果类、叶菜类蔬菜样品,研究了其中各种农药的残留情况,并分析了农药残留对环境的污染及其控制措施。结果表明:露地种植蔬菜与设施种植蔬菜相比,无论是农药残留检出率还是超标率都略高,两者的农药残留检出率分别为42.0%、36.5%,超标率分别为12.0%、8.2%;叶菜类蔬菜与瓜果类蔬菜相比,无论是农药残留检出率还是超标率都较高,两者的农药残留检出率分别为52.6%、29.6%,超标率分别为17.3%、5.4%;设施种植的瓜果类蔬菜和叶菜类蔬菜的农药残留检出率基本接近,而叶菜类蔬菜的农药残留超标率明显高于瓜果类蔬菜,露地种植的叶菜类蔬菜的农药残留检出率和超标率都远高于瓜果类蔬菜;设施种植蔬菜与露地种植蔬菜相比,甲胺磷、对硫磷、甲基对硫磷、毒死蜱、三氟氯氰菊酯和氰戊菊酯的残留检出率更高;瓜果类蔬菜与叶菜类蔬菜相比,毒死蜱、甲氰菊酯、三氟氯氰菊酯、氰戊菊酯的残留检出率更高;叶菜类蔬菜的农药施用浓度较高,施用农药后要间隔一定时间后再上市销售,并应采用更科学的施药方式,以减少农药在蔬菜中的残留和降低对环境的危害;一方面要开发并积极倡导使用高效、低毒、低残留的无公害农药,另一方面则要开发能够高效、快速降解残留农药的物质,同时还要进行农产品的清洁生产,以提高农产品的安全性,并降低环境中农药的残留危害。     

医疗废物焚烧处理核心技术的开发及应用

国内已建成的医疗废物焚烧设施目前普遍存在进料系统不稳定、玻璃结渣和高浓度HCl气体的排放的问题。这些技术难点已成为医疗废物焚烧处置行业发展的瓶颈。本文介绍了可解决上述问题的"可调节医疗废物恒流量进料技术"、"医废焚烧防玻璃结渣技术"和"含高浓度氯化氢医废尾气处理技术"三项医疗废物焚烧处理核心技术的主要特点及技术指标与应用实例。     

脱硫灰与钾矿石复合生产钾钙硅镁硫肥料研究

对脱硫灰与钾矿石复合生产钾钙硅镁硫肥的研究意义、反应原理、生产流程、环境安全性能以及施肥方法等进行了介绍和评估,并对其应用前景进行了展望。研究结果表明:利用脱硫灰与钾矿石复合生产钾钙硅镁硫肥在理论上可行;生产出的产品中硫酸钾的含量达10.34%～12.0%,枸溶氧化钙19.06%～32.28%,枸溶二氧化硅10.98%～14.46%,枸溶氧化镁1.46%～1.82%。产品的pH值从原脱硫灰的10.65下降到9.60。重金属含量低于农用粉煤灰国家标准,生产过程中不会产生SO2等有害气体污染。肥料的生产成本低于350元/t,该肥料不但可以增加土壤中钾、钙、硅、镁和硫等中微量元素的含量,而且可以提高或改善农作物的产量和品质。达到变废为宝,促进循环经济发展之目的。     

Fungicide sensitivity of Trichoderma spp. from Agaricus bisporus farms in Serbia

Trichoderma species, the causal agents of green mould disease, induce great losses in Agaricus bisporus farms. Fungicides are widely used to control mushroom diseases although green mould control is encumbered with difficulties. The aims of this study were, therefore, to research in vitro toxicity of several commercial fungicides to Trichoderma isolates originating from Serbian and Bosnia-Herzegovina farms, and to evaluate the effects of pH and light on their growth. The majority of isolates demonstrated optimal growth at pH 5.0, and the rest at pH 6.0. A few isolates also grew well at pH 7. The weakest mycelial growth was noted at pH 8.0–9.0. Generally, light had an inhibitory effect on the growth of tested isolates. The isolates showed the highest susceptibility to chlorothalonil and carbendazim (ED₅₀ less than 1 mg L^?1), and were less sensitive to iprodione (ED₅₀ ranged 0.84–6.72 mg L^?1), weakly resistant to thiophanate-methyl (ED₅₀ = 3.75–24.13 mg L^?1), and resistant to trifloxystrobin (ED₅₀ = 10.25–178.23 mg L^?1). Considering the toxicity of fungicides to A. bisporus, carbendazim showed the best selective toxicity (0.02), iprodione and chlorothalonil moderate (0.16), and thiophanate-methyl the lowest (1.24), while trifloxystrobin toxicity to A. bisporus was not tested because of its inefficiency against Trichoderma isolates.