环境pH条件下Fe2+活化过二硫酸盐降解有机污染物的效能与影响因素

利用Fe²⁺活化过二硫酸盐（PDS）产生SO₄^-·等高活性氧化物种是去除有机污染物的重要方法.然而该方法通常只有在酸性条件下才能获得良好的污染物去除效果,限制了Fe²⁺/PDS体系的实际应用.为此,分别从不同pH条件下Fe²⁺活化PDS降解水中有机污染物的效能、活性氧化物的种类和氧气的影响等角度,系统分析了中碱性条件下Fe²⁺/PDS体系难以氧化有机污染物的影响因素.结果发现,不同pH条件下Fe²⁺/PDS体系中均有SO₄^-·和Fe （Ⅳ）的生成;中碱性条件下溶解氧可与PDS竞争Fe²⁺,但此时仍有可观的PDS （37.6%~100%）得到了活化且排除氧气并不能提高污染物的去除效果.通过改变Fe²⁺的投量发现,过量的Fe²⁺会显著降低Fe²⁺/PDS体系对卡马西平的去除率,这表明过量的Fe²⁺对活性氧化物种是无谓消耗,是导致中碱性条件下Fe²⁺/PDS体系除污效能降低的重要原因.鉴于此,进一步探讨了零价铁或硫化零价铁替代Fe²⁺活化PDS去除污染物的可行性,并利用同步辐射技术分析了零价铁的腐蚀情况.结果为中碱性条件下PDS的有效活化和实际应用提供了理论支撑.     

沼渣与硫酸亚铁共处置含铬土壤的协同机制研究

利用沼渣和硫酸亚铁对含铬土壤进行共处置,在初步优化处置工艺参数后对共处置的协同效应进行验证,并通过XPS分析和微生物群落分析揭示了协同效用机理.结果表明,沼渣和硫酸亚铁共处置含铬土壤可实现土壤Cr (VI)含量低至未检出(检出限0.2mg/kg),优于硫酸亚铁处置法.共处置还原速率高于沼渣单独处置.微生物群落结构分析表明共处置组别细菌群落丰度与多样性高于沼渣单独处置,共处置土壤铬还原菌的相对丰度明显提高.此外,共处置组别内铁还原菌和硫酸盐还原菌的相对丰度也显著提升.通过XPS分析,共处置后的土壤中存在Fe (Ⅱ)、亚硫酸盐和硫化物,结合微生物群落分析结果,证实了铁和硫催化微生物还原六价铬过程.本研究为低碳型高浓度Cr (VI)污染土壤的治理提供新的思路.     

两段式还原工艺处理铬渣的生产性研究

利用焦亚硫酸钠和硫酸亚铁将铬渣中的六价铬进行两次溶出和两次还原,解毒后铬渣中总铬含量≤1.5 mg/L,六价铬含量≤0.5mg/L,远远低于HJ/T 301—2007《铬渣污染治理环境保护技术规范(暂行)》铬渣以一般工业固废进行固化填埋标准浓度值。该工艺技术解毒彻底,无返铬现象,过程简单,处理成本低,可实现规模化生产,具有广阔的推广应用前景,对周边环境的保护意义重大。     

Control of hydrogen sulphide in digestor gas using iron salts

Different dosages of ferrous chloride and ferric chloride were added to digestors separately, and the volumes of methane and hydrogen sulphide contained in the digestor gas (biogas) were monitored. It was noted that the effects of adding of 16, 18 and 32 kg ferrous chloride/ tonne volatile solids, and 16 and 18 kg ferric chloride/tonne volatile solids were similarly effective in controlling the hydrogen sulphide levels.

According to an average amount of undigested sludge (primary sludge mixed with surplus activated sludge) of 41 tonne volatile solids produced each day during the sewage treatment process in Shatin sewage treatment works, and the required dosage of 16 kg ferric chloride/ tonne volatile solids, the amount of iron salts required should be 656 kg/day or 3.3 mg/L for the actual application, based on an average sewage flow of 200,000 m³/day.     

次氯酸钠与亚铁对污泥破解及脱水效果的影响

采用次氯酸钠（NaClO）与亚铁（Fe（II））结合处理污泥以提高污泥破解和脱水效能,考察了NaClO和Fe（II）投加量的影响,并通过定量和定性分析污泥中胞外聚合物质（EPS）的迁移转化,确定NaClO和Fe（II）对污泥脱水和破解的机制.试验结果表明,NaClO和Fe（II）投加量（以干泥固体计）分别为44 mg·g^-1和66 mg·g^-1时,污泥毛细吸吮时间（CST）从原泥的112 s下降到66.3 s.同时,NaClO/Fe（II）处理污泥能够使上清液中化学需氧量（COD）显著升高,并使污泥中紧密束缚型EPS（TB-EPS）和松散束缚型EPS（LB-EPS）转化成溶解性EPS（S-EPS）,导致S-EPS的溶解性有机碳（DOC）含量升高,而LB-EPS和TB-EPS的DOC含量降低.此外,NaClO/Fe（II）还能使污泥中有机物质矿化,使3种EPS中蛋白质类和腐殖酸类物质减少.NaClO和Fe（II）能够改善污泥脱水性能,强化污泥破解效果,利于污泥后续的处理处置.     

Investigating the Use of Iron Reducing Bacteria for the Removal of Arsenic from Contaminated Soils

Clean-up techniques, which were developed for removing cationic heavy metals from contaminated soils, are inappropriate for the metalloid As, which is a common and highly toxic pollutant. Because arsenic is mainly found associated with the hydrous ferric oxides of the soil, a possible mechanism for the mobilisation of this element is the reductive dissolution of Fe(III) oxyhydroxides. In this paper we investigate the possibility to mobilise arsenic, using the Fe(III)-reducing bacterium Desulfuromonas Palmitatis. The initial experiments were carried out using a crystalline ferric arsenate as model compound, i.e. scorodite (FeAsO₄.2H₂O). D. palmitatis was found able to reduce the trivalent iron of scorodite at a percentage of 80% within 16 days, but arsenic remained in the pentavalent state, and reprecipitated with Fe(II) in the form of low solubility ferrous arsenates. To avoid the precipitation of ferrous arsenates the subsequent experiments with soil were conducted by combining the reducing ability of D. palmitatis with the chelating strength of EDTA (ethylenediamine tetracetic acid), which can form strong aqueous complexes with Fe(II). Approximately 60% of Fe and 75% of As were recovered in the aqueous solution in the presence of EDTA, while in the simple biological treatment no Fe was dissolved and only a 3% of As was mobilised.     

磷钼蓝分光光度法测定水中磷的改进

用硫酸亚铁铵和葡萄糖作为混合还原剂,建立了用分光光度法测定磷的方法,确定了最佳测定条件。在浓度为0.6mol/L的H2SO4介质中,硫酸亚铁铵-葡萄糖将磷钼杂多酸还原成杂多蓝,其最大吸收波长为820nm,表观摩尔吸光系数为1.38×104L/(mol·cm),PO3-4质量浓度在0～2.8mg/L范围内符合比耳定律,线性回归方程A=0.1453ρ 0.02744,相关系数(r)=0.9933。用硫酸亚铁铵-葡萄糖混合还原剂还原速度快,灵敏度高,产物稳定性好,线性范围宽。将该方法用于环境水样中磷的测定,结果令人满意。     

硫化亚铁自燃温度影响研究

硫化亚铁自燃是引起石油化工行业火灾爆炸事故的重要原因之一。为了规避此类事故的发生,利用自燃温度测试仪测定了不同粒径硫化亚铁以及硫磺与硫化亚铁混合物的自燃温度。结果表明:随着硫化亚铁粒径比表面积的增大,其自燃温度先减小后增大,之后随着粒径的继续增大,自燃温度基本保持平稳状态;硫磺与硫化亚铁混合物自燃温度彼此具有协同作用,其自燃温度比硫化亚铁自燃温度降低了116.3℃,使硫化亚铁自燃失控危险性大大增加,为采取安防措施带来了极大的不便。     

亚铁盐对二氧化氯杀藻副产物亚氯酸盐去除的研究

实验研究亚铁盐对来自于供水水库的含藻原水二氧化氯杀藻过程中产生的无机副产物亚氯酸盐去除的效果及亚铁盐的投加量,同时考察亚铁盐在去除亚氯酸盐的过程中的除浊作用。实验结果表明,FeSO4能完全去除二氧化氯杀藻的无机副产物亚氯酸盐。FeSO4在去除亚氯酸盐的同时也与二氧化氯反应而使二氧化氯的浓度降低。FeSO4的用量是亚氯酸盐和二氧化氯与FeSO4反应的理论用量的总和。在二氧化氯预氧化杀藻与投加FeSO4的时间间隔较短的情况下,FeSO4的投加量按照初始投加量70%的二氧化氯与FeSO4反应的化学计量关系计算确定,此时亚氯酸盐能完全被去除。FeSO4在去除亚氯酸盐的同时具有除浊作用,在饮用水的净化中可以减少常规混凝剂的用量,当浊度为23.3 NTU或24.3 NTU时,不需再投加常规混凝剂。FeSO4的絮凝作用对除藻有协同作用。     

亚铁离子活化过硫酸氢钾复合盐降解水溶液中萘普生

在不同pH值、Fe2浓度和过硫酸氢钾复合盐(PMS)浓度下,探究降解萘普生(NPX)的最佳条件,并通过分批投加Fe2+和改变投加顺序的方式,提高降解NPX的效率.结果表明,NPX在pH =3的条件下,降解效果最好;Fe2+浓度改变时,PMS/Fe2+/NPX=1/0.75/1条件下,NPX去除率最高;分批投加Fe2+和先投加Fe2+均可大幅提高NPX去除率.缓慢少量的产生硫酸根自由基(SO4--)更利于处理有机物,Fe2+的浓度则在产生自由基方面起着重要作用.