Fabrication of pollution-free coal gangue-based catalytic material utilizing ferrous chloride as activator for efficient peroxymonosulfate activation

Novel coal gangue-based persulfate catalyst(CG-FeCl_(2))was successfully synthesized by the means of calcinating under nitrogen atmosphere with the addition of ferrous chloride tetrahydrate(FeCl_(2)·_(4)H_(2)O).The phase transformation of the prepared materials and gas products during the heating process are thoroughly investigated.It is suggested that ferrous chloride participated in the phase transformation and formed Si-O-Fe bonds.And the main gaseous products are H_(2)O,H_(2),and HCl during the heating process.Besides,the ability of CG-FeCl_(2) to activate peroxymonosulfate(PMS)for catalytic degradation of polycyclic aromatic hydrocarbons(PAHs)and phenol was deeply studied.More than 95%of naphthyl,phenanthrene and phenol were removed under optimizied conditions.In addition,1O_(2),·OH,and SO_(4)·−were involved in the CG-FeCl_(2)/PMS system from the free radical scavenging experiment,where 1O_(2) played a major role during the oxidation process.Furthermore,CG-FeCl_(2)/PMS system exhibited superior stability in a relatively wide pH range and the presence of common anion from related degradation experiments.Overall,the novel CG-FeCl_(2) is an efficient and environmentally friendly catalyst,displaying potential application prospect in the field of PAHs and phenol-contaminated wastewater treatment.

Effect of different surfactants on removal efficiency of heavy metals in sewage sludge treated by a novel method combining bio-acidification with Fenton oxidation

The aim of this work was to investigate the effect of different surfactants on the removal efficiency of heavy metals in sewage sludge treated by a method combining bio-acidification with Fenton oxidation. Four surfactants were adopted such as anionic surfactant(sodium dodecyl benzene sulfonate, SDBS), nonionic surfactants(tween-20 and tween-60) and cationic surfactant(hexadecyl trimethyl ammonium chloride, HTAC), respectively. The indigenous sulfur-oxidizing bacteria in bio-acidification phase were enriched and cultured from fresh activated sludge obtained from a wastewater treatment plant. It is shown that different surfactants exhibited distinct effect on the removal efficiency of heavy metals from sewage sludge. The nonionic surfactants,especially tween-60, promotes the solubilization of heavy metals, while the anionic and cationic surfactants hinder the removal of heavy metals. Copper is efficiently leached. The removal efficiency of cadium is relatively lower than that of Cu due to the demand for rigorous p H value. Lead is leached with a low efficiency as the formation of low soluble Pb SO4 precipitates.

Effect of hydraulic retention time and pH on oxidation of ferrous iron in simulated ferruginous acid mine drainage treatment with inoculation of iron-oxidizing bacteria

The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.

Effect of Selenium on Root Oxidizing Ability and Yield of Rice under Ferrous Stress

To study the effects of selenium on root oxidizing ability and yield of rice under ferrous stress, a pot culture experiment was conducted, the activity of glutathione peroxidase (GSH-Px) and the concentration of malonaldelyde (MDA) were determined. The root oxidizing ability and yield characters of rice were examined. Results showed that appropriate amount of Se enhanced the activity of glutathione peroxidase and the oxidizing ability of rice roots significantly, reduced the concentration of MDA, increased 1000-grain weight of rice, F = 26.96**, decreased empty and blighted grain rate, increased the rice yield, F = 11.53**, and enhanced the rice resistance under ferrous stress.

Reduction Rate of Ferrous Oxide in Smelting Reduction

Reduction rate of ferrous oxide in smelting reduction with iron bath has been studied. The main affecting factors on reduction rate, such as composition of the melt, temperature of molten bath, basicity of slag and the way of supplying carbonaceous materials have also been investigated.

Isolation and characterization of ferrous-and sulfur-oxidizing bacteria from Tengchong solfataric region,China

Microbial oxidation and reduction of iron and sulfur are important parts of biogeochemical cycles in acidic environments such as geothermal solfataric regions. Species of Acidithiobacillus and Leptospirillum are the common ferrous-iron and sulfur oxidizers from such environments. This study focused on the Tengchong sofataric region, located in Yunnan Province, Southwest China. Based on cultivation, 9 strains that grow on ferrous-iron and sulfuric compounds were obtained. Analysis of 16S rRNA genes of the 9 strains indicated that they were affiliated to AcidithiobaciUus, Alicyclobacillus, Sulfobacillus, Leptospirillum and Acidiphilium. Physiological and phylogenetic studies indicated that two strains （TC-34 and TC-71） might represent two novel members of Alicyclobacillus. Strain TC-34 and TC-71 showed 94.8%-97.1% 16S rRNA gene identities to other species of Alicyclobacillus. Different from the previously described Alicyclobacillus species, strains TC-34 and TC-71 were mesophilic and their cellular fatty acids do not contain w-cyclic fatty acids. Strain TC-71 was obligately dependent on ferrous-iron for growth. It was concluded that the ferrous-iron oxidizers were diversified and Alicyclobacillus species were proposed to take part in biochemical geocycling of iron in the Tengchong solfataric region.

Effects of iron oxide on crystallization behavior and spatial distribution of spinel in stainless steel slag

Chromium plays a vital role in stainless steel due to its ability to improve the corrosion resistance of the latter.However,the re-lease of chromium from stainless steel slag(SSS)during SSS stockpiling causes detrimental environmental issues.To prevent chromium pollution,the effects of iron oxide on crystallization behavior and spatial distribution of spinel were investigated in this work.The results revealed that FeO was more conducive to the growth of spinels compared with Fe2O3 and Fe3O4.Spinels were found to be mainly distrib-uted at the top and bottom of slag.The amount of spinel phase at the bottom decreased with the increasing FeO content,while that at the top increased.The average particle size of spinel in the slag with 18wt%FeO content was 12.8μm.Meanwhile,no notable structural changes were observed with a further increase in FeO content.In other words,the spatial distribution of spinel changed when the content of iron oxide varied in the range of 8wt%to 18wt%.Finally,less spinel was found at the bottom of slag with a FeO content of 23wt%.

Study on Catalytic Wet Oxidation of H_2S into Sulfur on Fe/Cu Catalyst

A wet catalytic oxidation at room temperature was investigated with solution containing ferric, ferrous and cupric ions for H2S removal. The experiments were carried out in a two step process, and the results obtained show that the removal efficiency of H2S can always reach 100% in a 300 mm scrubbing column with four sieve plates, and the regeneration of ferric ions in 200 mm bubble column can match the consumed ferric species in absorption. Removal of H2S, production of elemental sulfur and regeneration of ferric, cupric ions can all be accomplished at the same time. No raw material is consumed except O2 in flue gas or air, the process has no secondary pollution and no problem of catalyst degradation and congestion.

Fe(Ⅱ)非生物氧化-沉淀联合工艺对As(Ⅴ)去除的研究

由于现代化工业进程快速发展,大量砷污染物进入水体,引起水质恶化。提出了氧诱导Fe(Ⅱ)非生物氧化与As(Ⅴ)共沉淀,是一种节省成本、时间且高效的As(Ⅴ)去除方法。考察了pH、Fe(Ⅱ)/As(Ⅴ)摩尔比、溶解氧(DO)浓度、温度及共存离子对As(Ⅴ)去除的影响。结果表明,同步氧化Fe(Ⅱ)可显著提高亚铁除砷效率。随着pH从5.3增加到8.0,As(Ⅴ)去除能力先增大后减小,最佳pH为6.4;溶解氧质量浓度从0提高到4 mg/L,反应60 min后As(Ⅴ)的去除率提升了37.85%;反应体系中共存离子(Cu^(2+)、Ni^(2+)、Mn^(2+)、Cl-、NO_(3)^(-)、PO_(4)^(-))存在时,Mn^(2+)促进As(Ⅴ)的去除,Mn(Ⅱ)=0.5 mg/L,As(Ⅴ)的去除率提高了11%;提高温度和亚铁浓度均能增加As(Ⅴ)的去除率。SEM-EDS结果表明,氧气存在时固体颗粒由松散细小转化为轮廓清晰、簇团密实的球形团聚,颗粒粒径增大,增强了As(Ⅴ)的固定。以活性氧(ROS)为氧化剂,与Fe(Ⅱ)发生类Fenton反应是Fe(Ⅱ)氧化的机理,砷酸铁和含砷的铁(氢)氧化物是砷固定的主要形态。

盐度对硝酸盐还原型铁氧化菌亚铁氧化与硝酸盐还原的影响研究

作为重要的嗜中性铁氧化菌,硝酸盐还原型铁氧化菌一直以来都被认为是在环境污染修复中具有广阔应用前景的一类微生物,其广泛分布于淡水沉积物、地下水、稻田土壤、海岸沉积物等各种盐度的水土环境中。已有研究指示,盐度可能会对此类铁氧化菌的生长代谢和亚铁氧化过程产生抑制作用,但是具体作用机制尚不清楚。为深入探究盐度对硝酸盐还原型铁氧化菌生长代谢的影响,选取Acidovorax sp.BoFeN1为模式菌株,设置微宇宙培养实验,并利用NaCl调节反应体系盐度(NaCl质量浓度分别为0、15、35、55 g·L^(-1))。通过监测反应过程中亚铁离子和硝酸盐的浓度变化,并对产物进行矿物学表征,探究硝酸盐还原型铁氧化菌在不同盐度条件下亚铁氧化和硝酸盐还原过程;进一步设置真实海水(盐度为34 g·L^(-1))的模拟实验对实验结果进行验证。亚铁氧化和硝酸盐还原动力学结果表明,尽管低浓度氯化钠影响不大,但当NaCl质量浓度为35 g·L^(-1)和55 g·L^(-1)时,Acidovorax sp.BoFeN1的亚铁氧化和硝酸盐还原过程会被促进。利用SEM、XRD和FTIR对反应终点产物进行物相分析,结果显示盐度会促进微生物亚铁氧化成矿类型由纤铁矿向针铁矿转变。最后,真实海水验证实验表明,在海水提供的盐度条件下Acidovorax sp.BoFeN1的亚铁氧化和硝酸盐还原能力分别提升了1.2倍和1.3倍;此时,微生物亚铁氧化的成矿类型为纤铁矿和针铁矿。这一结果与微宇宙培养实验所得结论一致。从环境意义上看,该研究证明了硝酸盐还原型铁氧化菌能够适应海水入侵等高盐水土污染环境,更新了盐度抑制细菌代谢的传统认识,这将有助于推动此类细菌在高盐环境污染修复中的应用。

普鲁士蓝类钠电池正极生产废水预处理工艺研究

钠离子电池作为新兴产业,有关其生产工艺的研究较多,但是鲜少见到关于钠电池生产废水处理工艺的研究。因此,本文对普鲁士蓝类钠电池正极废水的预处理工艺进行实验研究,探究最佳处理工艺。最终确定了母液废水采用直接氧化法预处理工艺,即先加入H_(2)O_(2)(1.18倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9左右,静置30 min,再经过管式超滤膜过滤,母液中铁锰元素的去除率分别约为99.93%和99.99%。洗水废水采用两段式沉淀法预处理工艺,即第一阶段采用固氰除铁法,先用质量分数为30%的NaOH溶液调pH至7左右然后加入硫酸亚铁(硫酸亚铁投入量与废水中铁元素质量比为5.2),反应静置30 min。主要去除废水中绝大部分的铁元素和少部分锰元素。在一段处理的基础上再采用氧化沉淀法,先加入H_(2)O_(2)(0.83倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9,反应静置30 min,再经过管式超滤膜过滤,最终铁和锰元素的去除率分别约为99.87%和99.99%。为实际工程中钠电池废水预处理提供了重要技术参考。

Reaction behavior of ferric oxide in system Fe_2O_3-SiO_2-Al_2O_3 during reductive sintering process

Pure compounds and kaolin were employed to investigate the reaction behavior of ferric oxide in thetrinarysystem Fe2O3?SiO2?Al2O3 during reductive sintering process. The thermodynamic analyses and reductive sintering experimental results show that ferrous oxide generated from the reduction of ferric oxide by carbon can react with silicon dioxide and aluminum oxide to form ferrous silicate and hercynite at 1173 K, respectively. In the trinary system Fe2O3?SiO2?Al2O3, ferrous oxide obtained from ferric oxide reduction preferentially reacts with aluminum oxide to form hercynite, and the reaction of ferrous oxide with silicon dioxide occurs only when there is surplus ferrous oxide after the exhaustion of aluminum oxide. When sintering temperature rises to 1473 K, hercynite further reacts with silicon dioxide to form mullite and ferrous oxide. Results presented in this work may throw a new light upon the separation of alumina and silica present in Al/Fe-bearing materials with low mass ratio of alumina to silica in alumina production.

羟基乙叉二膦酸对Fe^(2+)活化O_(2)降解污染物的强化效果及机制

羟基乙叉二膦酸(HEDP)常与Fe^(2+)形成Fe^(2+)-HEDP配合物,本文验证了HEDP存在可以促进Fe^(2+)活化分子氧产生活性自由基(ROS),研究结果显示添加2mmol/L HEDP后,Fe^(2+)/O_(2)体系中苯酚(10mg/L)的降解效果从0.69%提升到69.31%,在此过程中,体系中的HEDP还能够实现部分自降解.电子自旋共振(ESR)和掩蔽实验结果表明体系中主要ROS为HO^(•)和O_(2)^(•–),双电子传递途径(O_(2)→H_(2)O_(2)→HO^(•))是体系中产生HO^(•)的主要方式.在3.0~9.0的pH值范围内,HEDP都能够促进ROS的产生和污染物的降解,常见环境阴离子对体系影响较小.

硫酸亚铁废液的综合回收利用

在工业生产中每年都会产生大量的硫酸亚铁废液,其中钢铁深加工过程的产出量最大。硫酸亚铁废液中含有硫酸,pH值较低,且含有铁、钴、镍、铝、铬等金属离子,直接排放不仅浪费其中的金属资源,还会对土壤和水体造成严重污染。综合回收硫酸亚铁废液对企业具有巨大的经济效益,对社会具有一定的环境效益。目前主要的处理方法有中和处理法、化学沉淀法、结晶析出法、溶剂萃取法、微生物法等。针对不同生产过程产生的硫酸亚铁废液应采用相应的处理办法。由于中和处理法产生大量金属污泥、结晶析出法的产品市场需求低、溶剂萃取法处理能力低、微生物法处理周期长,化学沉淀法是目前主要采用的回收方法。化学沉淀法操作简单、无需高性能设备,但试验影响因素多,产品性质波动大。硫酸亚铁废液回收产品主要被应用于颜料行业、水处理行业、磁性材料行业等。多数产品仅利用了废液的铁元素,而硫酸和硫元素并未得到回收利用,如何对废液进行综合回收是一个研究重点。由于硫酸亚铁废液中杂质元素含量较多,对其进行提纯具有很大的难度,所需生产成本也较高,因此如何直接利用废液也是未来研究的主要方向。

影响Sulfobacillus thermosulfidooxidans生长及亚铁氧化的因素研究

在测定 Sulfobacillus thermosulfidooxidans生长曲线的基础上 ,以 Fe2 +的氧化表征细菌的生长规律 ,考察了初始 p H、接种量、初始 Fe2 +浓度对细菌生长及亚铁氧化的影响。实验结果表明 ,在混合营养条件下 ,初始 p H1 .6、接种量 1 0 %、初始 Fe2 +浓度 50～ 1 0 0 m mol/ L适宜细菌的生长及亚铁的氧化。

硝酸盐依赖型亚铁氧化研究进展

传统生物反硝化受限于废水中碳源的不足导致总氮去除率低,在实际处理中需要额外投加碳源。硝酸盐依赖型亚铁氧化(NDFO)作为一种经济且无二次污染的自养反硝化技术,可有效应对进水碳源不足的问题。本文总结了NDFO反应原理与NDFO功能微生物,通过阐述乙酸盐对NDFO的影响以及NDFO与Feammox的耦合,综述了NDFO的脱氮强化措施。

粉煤灰酸法生产氧化铝过程中气体氧化剂氧化Fe^(2+)的动力学研究

对粉煤灰酸法生产氧化铝浸出液进行化学成分分析,结果显示:浸出液中铝、铁为主要元素,以氯化铝计的铝质量浓度为263.5 g/L,以FeO计的总铁质量浓度为4.4 g/L,Fe^(2+)质量浓度为2.17 g/L。开展了空气、富氧气体、臭氧气体氧化Fe^(2+)的氧化反应动力学研究,得到了3种气体氧化剂氧化Fe^(2+)的动力学方程,对比了3种气体氧化剂的氧化速率,发现臭氧气体氧化速率是富氧气体的1.7倍,是空气的1.9倍。

滴定硅酸盐岩石与土壤中氧化亚铁的对比研究

【研究目的】由于硅酸盐岩石与土壤的成分不同,开展硅酸盐岩石与土壤中氧化亚铁的对比研究有利于更加准确地滴定氧化亚铁的含量。【研究方法】本文对重铬酸钾滴定法滴定硅酸盐岩石与土壤中氧化亚铁进行了对比,重点比较了溶样时间对氧化亚铁的影响,实验使用硫酸(1+1)和氢氟酸溶样,多余的氟用硼酸络合,以二苯胺磺酸钠为指示剂,重铬酸钾标准溶液滴定氧化亚铁。【研究结果】分析结果表明,溶样时间对硅酸盐岩石和土壤中氧化亚铁影响较大,硅酸盐岩石和土壤样品分别在溶液完全沸腾0~2 min和8~10 min时滴定为宜;方法经国家一级标准物质分析验证,结果与参考值相符,硅酸盐岩石和土壤的精密度RSD(n=10)分别为1.94%、1.78%。【结论】因此,在实际操作中应根据样品的类型选择合适的溶样时间,能够更加准确地确定氧化亚铁的含量。

高酸液体硫酸亚铁在污水芬顿处理中的应用

以不锈钢酸洗废硫酸经扩散渗析分离得到的稀硫酸和渗析残液为研究对象,残液经铁粉除杂后得到高纯硫酸亚铁水,高纯硫酸亚铁水与扩散渗得到的回收酸配置成高酸硫酸亚铁溶液,进行污水芬顿处理试验,考察了双氧水添加量、硫酸亚铁添加量、硫酸用量等因数对芬顿处理效果的影响,并与低酸液体硫酸亚铁、固体硫酸亚铁处理效果进行比较,高酸液体硫酸亚铁在污水芬顿处理中效果好,成本低,值得推广。

基于六偏磷酸钠-Fe^(2+)的铁盐脱氮反应器运行性能及微生物学特征研究

以实验室高效反硝化反应器中的反硝化污泥作为接种污泥,启动自养型六偏磷酸钠-Fe^(2+)脱氮反应器,试验采用模拟废水通过88 d的不间断运行,研究了铁盐脱氮工艺的脱氮效能及其微生物学特性。结果表明,当反应器硝态氮容积负荷为0.42 kg/(m^(3)·d)时,最高稳定氮去除负荷为0.41 kg/(m^(3)·d);当Fe^(2+)容积负荷为4.92 kg/(m^(3)·d)时,最大铁去除负荷为2.77 kg/(m^(3)·d)。反应器稳定运行时硝态氮、Fe^(2+)的去除率分别达94.6%、52.6%,最佳效能可维持28 d。反应器运行到第82天时,颗粒污泥由黄色变为灰褐色,颗粒解体,污泥比活性逐渐升高,比反硝化活性由0.71 mg[N]/(g[VSS]·h)升高到2.3 mg[N]/(g[VSS]·h),同比上升224%;比铁氧化活性由7.3 mg[Fe]/(g[VSS]·h)升高到15 mg[Fe]/(g[VSS]·h),同比上升105%。六偏磷酸钠-Fe^(2+)脱氮作为一种新型自养反硝化技术,不仅增强了活细菌的生物活性和反硝化活性,还延长了铁盐脱氮污泥反硝化的高效期。