低浓度硫化氢废气的液相催化氧化法净化实验研究

针对H2S浓度为750~1500mg/m3的气体的液相催化氧化技术进行了动力学实验研究。配制了以铁基离子作为主催化剂的复合吸收净化溶液,同时加入稳定剂和表面活性剂提高催化剂在碱性吸收溶液的活性。分别考察了原料气中H2S、O2含量以及吸收液中催化剂离子浓度、温度等因素对吸收速率的影响;确定了较为理想的吸收操作条件并获得了较好的吸收净化效果;饱和吸收液易于再生,净化性能恢复良好,可重复使用。     

COS,CS2 and SO2 in aluminium smelter exhaust

Measurements of carbonyl sulfide (COS) and carbondisulfide (CS₂) were carried out on samples drawn from a smoke stack of an aluminium smelter. Volume mixing ratios of 6 ppm COS and 0.1 ppm CS₂ were measured for gases from the electrolysis unit that had previously passed an Al₂O₃ fluid bed reactor and electrostatic precipitators. Specific emissions of 1.6 kg COS and 0.03 kg CS₂ per ton of primary aluminium were found. Extrapolating from this particular smelter’s conditions to a world mix specific COS emissions of about 4 kg/t(Al) are calculated resulting in emissions of annually 0.08 Tg COS into the atmosphere due to electrolytic aluminium production in 1995. Besides the photochemical conversion of anthropogenic CS₂ aluminium production is established to be the second major industrial source of COS probably exceeding automotive tire wear’s and coal combustion’s contributions.     

硫化氢气体快速检测方法研究

研究了快速监测硫化氢气体的新方法——硫化氢被动式检气管方法。该法是基于气体分子扩散(Fick)定律和化学吸收原理,将检气管内的海棉载体涂渍上对硫化氢有特效的显色剂(缓冲液G和醋酸铅)。测定时,硫化氢通过检气管端口扩散进入管内,在经过载体时,与载体上的显色剂发生反应,从而产生明显的颜色变化(浅黄色变成棕黑色)。检气管显色长度的平方与硫化氢质量浓度及采样时间的乘积在50~1500mg·m-3范围内成线性关系,从而快速监测环境中硫化氢的时间加权平均质量浓度。该检气管集采样与分析为一体,可快速测定硫化氢气体的质量浓度。与传统的采样分析方法比较,该检气管结构简单,操作方便,不受被测环境的空间大小、有无电源等影响;携带方便,利于外出测定和大面积布点测定。经过应用实验表明,该检气管具有较高的灵敏度,达到设计要求。     

垃圾填埋场硫化氢恶臭污染变化的成因研究

通过对阿苏卫填埋场沼气工程改造前期和后期污染状况的现场监测，重点分析北方平原型填埋场H2S产生原因和影响因素。结果表明，沼气工程改造前期，填埋区内新鲜垃圾年填埋高度为2m时，H2S质量浓度随季度有显著的变化，其浓度峰值出现在9月，可达179．1mg／m^3；新鲜垃圾年填埋高度为0．5m时，H2S质量浓度的季度性变化不明显，峰值仅为21．8mg／m^3；这是新鲜垃圾含水率的季度性变化和年填埋高度共同作用的结果。沼气上程改造后期(2003年6～7月)，在渗滤液收集井内，H2S的浓度变化趋势与水而蒸发量的变化趋势有良好的相关性。平均38℃的堆体内部温度和垃圾降解过程的pH值决定其浓度变化。填埋场H2S气体丰要在填埋区释放。因此，控制新鲜垃圾年填埋高度，足控制H2S质量浓度季节性变化和出现高峰值的关键。     

Re-Os同位素体系在金属矿床研究中的应用

Re－Os法能够对金属硫化物矿物直接进行同位素定年，并可以根据矿物的Os同位素初始比值探讨成矿物质来源。它的研究对象还包括黑色页岩和洋底含金属沉积物等。普通Os法可以用于铂族元素矿物定年和成矿物源区的讨论。近年由常规Re－Os法衍生的Os－Os法有可能避免前者在定年技术方面的一些困难。Re-Os同位素体系为成矿年代学研究提供了广阔的前景。     

铬在土壤和地下水中的相互迁移规律及地下水中铬的去除方法

本文以泰安市一处多年前受电镀铬严重污染地区为研究对象,对比研究六价铬在不同岩土中吸附、转化及迁移的特征和规律,铬易在水土共存的含水层中富集,并可转移到地下水中.土壤中三价铬可引起潜在的危害.水体中六价铬在富氧的情况下是稳定的,并能维持一个较长的时期.铁盐是一种较好的除铬剂,可以有效地去除水中六价铬离子,从而提高了地下水的利用价值.     

Surface characterization of metal oxides-supported activated carbon fiber catalysts for simultaneous catalytic hydrolysis of carbonyl sulfide and carbon disulfide

The sol–gel method was used to synthesize a series of metal oxides-supported activated carbon fiber (ACF) and the simultaneous catalytic hydrolysis activity of carbonyl sulfide (COS) and carbon disulfide (CS₂) at relatively low temperatures of 60°C was tested. The effects of preparation conditions on the catalyst properties were investigated, including the kinds and amount of metal oxides and calcination temperatures. The activity tests indicated that catalysts with 5 wt.% Ni after calcining at 400°C (Ni(5)/ACF(400)) had the best performance for the simultaneous catalytic hydrolysis of COS and CS₂. The surface and structure properties of prepared ACF were characterized by scanning electron microscope-energy disperse spectroscopy (SEM-EDS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), carbon dioxide-temperature programmed desorption (CO₂-TPD) and diffuse reflectance Fourier transform infrared reflection (DRFTIR). And the metal cation defects were researched by electron paramagnetic resonance (EPR) method. The characterization results showed that the supporting of Ni on the ACF made the ACF catalyst show alkaline and increased the specific surface area and the number of micropores, then improved catalytic hydrolysis activity. The DRFTIR results revealed that -OH species could facilitate the hydrolysis of COS and CS₂; -COO and -C–O species could facilitate the oxidation of catalytic hydrolysate H₂S. And the EPR results showed that high calcination temperature conditions provide more active reaction center for the COS and CS₂ adsorption.     

Town-scale microbial sewer community and H2S emissions response to common chemical and biological dosing treatments

Controlling hydrogen sulfide (H₂S) odors and emissions using a single, effective treatment across a town-scale sewer network is a challenge faced by many water utilities. Implementation of a sewer diversion provided the opportunity to compare the effectiveness of magnesium hydroxide (Mg(OH)₂) and two biological dosing compounds (Bioproducts A and B), with different modes of action (MOA), in a field-test across a large sewer network. Mg(OH)₂ increases sewer pH allowing suppression of H₂S release into the sewer environment while Bioproduct A acts to disrupt microbial communication through quorum sensing (QS), reducing biofilm integrity. Bioproduct B reduces H₂S odors by scouring the sewer of fats, oils and grease (FOGs), which provide adhesion points for the microbial biofilm. Results revealed that only Mg(OH)₂ altered the microbial community structure and reduced H₂S emissions in a live sewer system, whilst Bioproducts A and B did not reduce H₂S emissions or have an observable effect on the composition of the microbial community at the dosed site. Study results recommend in situ testing of dosing treatments before implementation across an operational system.     

氧化环境中FeS修复重金属的稳定性变化与机制

硫化亚铁(FeS)是良好的重金属修复剂,但它对氧化环境敏感.当环境氧气浓度升高时,FeS对重金属的固定效果可能发生改变.本研究考察了氧化环境中FeS与重铬酸根、铅和镉离子的反应规律和结合机制变化.结果表明,环境氧气浓度升高可促进Fe~(2+)的释放,且增加FeS表面S(-II)氧化态的比例(与Pb~(2+)反应:从24%增加到44%,与Cd~(2+)反应:从60%增加到78%).延长反应时间至30 d,虽然PbS和CdS结晶度提高,但两者表面出现Pb—O和Cd—O氧化形态,预示着重金属再释放的风险.有氧干燥条件下FeS表面矿物相转变为纤铁矿,对Cr(VI)的还原能力大幅下降.与未干燥FeS(FeS-Cr-3h)相比,当有氧干燥的FeS与Cr(VI)反应时,总铬的去除量下降约96%(由约100 mg·g~(-1)降至(3.74±1.12) mg·g~(-1)),Cr(VI)去除量下降约57%(由约100 mg·g~(-1)降至(43.28±0.46) mg·g~(-1)).FeS及重金属硫化物的氧化显然不利于重金属的长期稳定.如何延缓或抑制FeS与重金属硫化物的氧化因此成为未来研究需回答的问题.     

荧光灯管芯柱玻璃中金属铅的机械化学硫化

以硫化钠为硫化剂,机械化学硫化荧光灯管芯柱玻璃中金属铅,实现金属铅向硫化铅快速转化.通过单因素实验,考察了不同机械化学硫化条件,即球磨时间、球磨转速和球料比对硫化率的影响,并通过XRD、SEM和粒度对硫化产物进行表征.结果表明,硫化率随球磨时间和球磨转速的增大而增大,随球料比的增大先增大后减小,当球磨转速为750r/min、球磨时间为120min、球料比为50：1g/g时,荧光灯管芯柱玻璃中金属铅的硫化率可达96.18%.XRD结果表明,荧光灯管芯柱玻璃中金属铅的机械化学硫化产物为PbS、SEM和粒度结果表明,荧光灯管芯柱玻璃的粒径随球磨转速和球磨时间的增加而减小.