Treatment of naphthalene derivatives with iron-carbon micro-electrolysis

The degradation of five naphthalene derivatives in the simulated wastewater was investigated using the iron-carbon micro-electrolysis method.The optimal initial pH of solution and adsorption of iron-carbon and removal efficiency of the total organic carbon(TOC)were investigated.The results show that the removal efficiency of the naphthalene derivatives can reach 48.9%?92.6% and the removal efficiency of TOC is 42.8%?78.0% for the simulated wastewater with 200 mg/L naphthalene derivatives at optimal pH of 2.0?2.5 after 120 min treatment.The degradation of five naphthalene derivatives with the micro-electrolysis shows the apparent first-order kinetics and the order of removal efficiency of the naphthalene derivatives is sodium 2-naphthalenesulfonate,2-naphthol,2,7-dihydroxynaphthalene,1-naphthamine,1-naphthol-8-sulfonic acid in turn.It is illustrated that the substituents of the naphthalene ring can affect the removal efficiency of naphthalene due to their electron-withdrawing or electron-donating ability.

Structural parameter optimization for novel internal-loop iron–carbon micro-electrolysis reactors using computational fluid dynamics

It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.

Degradation of Nitrobenzene Wastewater via Iron/Carbon Micro-electrolysis Enhanced by Ultrasound Coupled with Hydrogen Peroxide

The zero valent iron/granular active carbon(ZVI/GAC) micro-electrolysis enhanced by ultrasound(US) coupled with hydrogen peroxide(H_2O_2) was investigated for the deep degradation of nitrobenzene-containing wastewater. The results of scanning electron microscopy-energy dispersive X-rays analysis(SEM-EDS) demonstrated that continuously accelerated regeneration of ZVI and GAC in situ by US could improve the process for converting nitrobenzene(NB) to aniline(AN). H_2O_2 was decomposed catalytically by the byproduct Fe^(2+) ions generated in the micro-electrolysis process to hydroxyl radicals and the organic pollutants in the wastewater were finally mineralized to CO2 and H2O. Effects of the ZVI dosage, the ZVI/GAC mass ratio, the initial pH value and the H_2O_2 dosage on the efficiency for degradation of NB were studied in these experiments. The optimal operating conditions covered a ZVI dosage of 15 g/L, a ZVI/GAC mass ratio of 1:2,an initial pH value of 3 and a H_2O_2 dosage of 4 mL. In this case, the NB removal efficiency reached 97.72% and the total organic carbon(TOC) removal efficiency reached 73.42% at a NB concentration of 300 mg/L. The reduction of NB by USZVI/GAC followed the pseudo-first-order kinetics model, and the pseudo-first-order rate constants were given at different initial pH values. The reaction intermediates such as AN, benzoquinonimine, p-benzoquinone, p-nitrophenol and other organic acids were detected and a probable pathway for NB degradation has been proposed.

氮、硫双掺杂荧光碳点制备及用于铁离子检测研究

目的建立基于荧光碳点快速检测铁离子的新方法。方法以邻苯二胺和Na_(2)SO_(4)为前驱体,采用水热法制备氮、硫双掺杂荧光碳点,对碳点的形貌、表面官能团以及光学性能等进行表征;同时制备了荧光碳点功能化纸基芯片,利用碳点的荧光淬灭实现铁离子快速检测。结果成功合成了氮、硫双掺杂荧光碳点,碳点的荧光强度与铁离子浓度在1×10^(-3)~20 mM范围内呈良好的线性关系(r^(2)=0.9812),检测限为0.066μM,血清加标回收率为99%~106%,RSD值小于4%;利用荧光碳点功能化纸基芯片,实现对铁离子的可视化检测。结论该方法简便、快捷,特异性好,对于开发成本低的铁微量元素检测方法具有重要参考价值。

Reduced graphene oxide-nano zero value iron(rGO-nZVI) micro-electrolysis accelerating Cr(Ⅵ) removal in aquifer

Nanoscale zero-valent iron （nZVI） assembled on graphene oxide （GO） （rGO-nZVI） composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr（VI） removal from aqueous solution. The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe0, thus overcoming the bottleneck of aggregation for nZVI. Also, rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr（VI）-contaminated aquifers, enhancing and accelerating electron transfer, exhibiting high rate and capacity for Cr（VI） removal. The optimum dosage of the applied rGO-nZVI was linearly correlated with the initial Cr（VI） concentration. Characterization of rGO-nZVI before and after reaction with Cr（VI） revealed the process of Cr（VI） removal： rGO-nZVI firstly transferred electrons from Fe0 cores via their Fe（II）/Fe（III） shells to the GO sheet; there, negatively charged Cr（VI） received electrons and changed into positively charged Cr（III）, which was adsorbed by the negatively charged GO sheet, avoiding the capping and passivating of nZVI rGO-nZVI formed a good electrically conductive network, and thus had long-term electron releasing properties, which was important for groundwater remediation.

Arsenic and chromate removal from water by iron chips-Effects of anions

The purpose of this study is to estimate the removal efficiency of As and Cr(VI)by one kind of industrial waste–iron chips,as well as to estimate the effects of typical inorganic anions(sulfate,phosphate,and nitrate),and typical organic anions(citrate,oxalate,and humate)on As or Cr(VI)removal.The results showed that 98%of As(V)and 92%of As(III)could be removed from aqueous phase by the iron chips within 60 min.Compared with As species,Cr(VI)was removed much more rapidly and efficiently with 97%of Cr(VI)being removed within 25 min.The removal efficiency for arsenic was in the order:As(III)(sulfate),As(III)(nitrate)or As(III),As(III)(humate),As(III)(oxalate),As(III)(citrate),As(III)(phosphate),and for chromate was in the order:Cr(VI)(sulfate),Cr(VI)(phosphate)or Cr(VI)(nitrate)or Cr(VI)(oxalate),Cr(VI),Cr(VI)(citrate),Cr(VI)(humate).In all the treatments,pH level increased with time except for As(III),the removal of which was either without anions or in the presence of humate or nitrate.

铁屑微电解法处理电解锰生产废水

用废铁屑为原料对电解锰生产废水进行处理 ,考察了铁屑用量、反应时间和废水pH值对Cr6+ ,Mn2 + 去除率的影响 .实验结果表明 ,在铁屑用量为 15 % ,废水pH值为 4 ,常温下反应 12 0min的条件下 ,Cr6+ ,Mn2 + 的去除率在 99.7%以上 ,总铬去除率达 99.2 % .同时 ,将实验结果用于工厂废水处理运行 ,效果良好 ,Cr6+ 的去除率为 99.4 5 % ,Mn2 + 的去除率为95 .5 3% .

铁屑内电解法对苎麻废水的预处理研究

在研究铁屑内电解工艺的基本原理和反应机理的基础上,通过正交实验和单因素影响试验,研究各工艺因素对处理效果的影响。实验结果显示,在pH越低、停留时间越长、通气量越大、温度越高的情况下,处理效果越好,影响大小依次为:pH值→温度→通气量→停留时间。色度和CODCr的去除率分别在40%和30%左右,且可生化性提高,达到了预处理的目的。对pH和停留时间进行的单因素实验发现pH在2～4效果最好,停留时间在40min以上,处理效果趋于稳定。为研究添加剂对处理效果的影响,特选定三氧化二铝、二氧化锰和氧化铜这几种金属氧化物作为添加剂,在相同的条件下,添加不同比例不同的金属氧化物后,处理效果均有提高。

铁屑法处理含染料废水中铁屑表面化学研究

采用扫描电镜和X射线光电子能谱技术对铁屑法处理含染料废水中铁屑反应前后的表面进行了研究 ,结果表明 :铁屑表面主要由Fe ,C ,O ,S,Si以及其它构成铸铁的微量元素等组成 .铁屑表面快速氧化是染料脱色的关键和前提步骤 ,铁屑表面铁的羟基氧化物增多是铁屑失活的重要原因 .超声方法是铁屑再生方法之一 .

油田酸化废水COD去除方法的研究

油田酸化废水由于所含添加剂种类繁多 ,且有机成分复杂 ,使COD值的降解难度增大。本实验以磨 140井为研究对象 ,通过大量室内实验 ,提出了“中和 -Fe/C微电解 -催化氧化 -活性炭吸附”四步法处理工艺。实践证明 ,该处理工艺流程简单、处理效果较好。

铁屑腐蚀电池在工业废水治理中的应用

用铁屑腐蚀电池处理工业废水是一种比较新的方法，目前在印染废水、石油化工废水、砷氟废水及电镀废水等的治理方面得到应用，并取得了较好的效果，作者就其上述处理过程的机理作了简要介绍，也对他们近阶段在废水处理方面的工作进行了总结。

铁屑微电解法处理光致抗蚀剂废水的研究

采用色谱 -质谱联用分析仪和电感耦合等离子体发射光谱仪分析和鉴定了光致抗蚀剂废水中的污染物。结果表明 ,污染物的去除或降解是铁的还原、铁的电化学腐蚀、活性炭吸附和铁离子、亚铁离子混凝沉淀等机理共同作用的结果 ;废水中铜、锌、钒、锡等无机污染物的去除率分别为 1 0 0 % ,4 7.0 % ,1 0 0 % ,98.1 %。邻苯二甲酸酐、聚丙二醇、丁烯酸、苯甲酸等有机物去除率分别为 1 0 0 % ,2 9.9% ,2 7.7% ,5 6 .5 %。硝基苯、2 -氯代苯甲酸等污染物的降解率分别为 1 0 0 %。

铁屑法脱色效率与染料结构的关系

33种水溶性染料溶液的铁屑法脱色试验结果表明,所有染料在10min内脱色率达到55%以上,其中33%的染料脱色率超过90%,61%的染料脱色率超过80%.初步探讨了染料结构与其铁屑法脱色效率之间的定性关系.结果表明,铁屑法脱色效率与染料结构之间有较密切关系,染料共轭链的长短、染料分子空间位阻的大小、是否有互变异构现象、偶氮双键中的氮原子是否与临近基团形成氢键以及取代基的电负性大小等对脱色效果有影响.

铁屑—炭粒法处理纺织印染废水

采用铁屑和炭粒材料所构成的内电解装置处理纺织印染废水，结果表明铁屑炭粒法对纺织印染废水的脱色率和ＣＯＤ去除率为７５％～９０％，同时提高纺织印染废水的可生化性，为进一步生化处理创造了有利条件。

零价铁Fenton技术处理含聚乙烯醇的印染退浆废水

采用零价铁Fenton技术处理含聚乙烯醇（PVA）的印染退浆废水。通过单因素实验和正交实验,考察了初始pH、H2O2投加量、铁屑粒径及投加量和反应时间对实验结果的影响。结果表明,初始pH和H2O2投加量对处理效果影响很大。最佳反应条件是初始pH=4.0,H2O2投加量为100mmol/L,铁屑（粒径为〉1~3mm）投加量为15g/L,反应时间为30min。在该条件下,出水PVA质量浓度为0.9mg/L,PVA去除率为99.9%,COD去除率为23.6%,BOD5/COD由0.12升高至0.34,可生化性明显提高。无论从处理效果考虑还是从成本考虑,零价铁Fenton技术都优于传统Fenton技术。

电动力和铁PRB技术联合修复铬(Ⅵ)污染土壤

考察了电动力学方法对模拟铬(Ⅵ)污染土壤以及天津市原同生化工厂遗留下的铬渣山周边土壤的修复效果,并将该技术与铁可渗透反应格栅(permeable reactive barrier,PRB)技术联用,找出了较好的联用方式,与单一电动修复进行了对比.研究表明,电动力学技术能有效地修复被铬(Ⅵ)污染的土壤,模拟污染土壤铬(Ⅵ)的去除率达98%-100%,总铬去除率在阳极室附近为80%左右,而阴极室附近则为90%以上,恢复到土壤背景值;铬(Ⅵ)去除的同时伴随着铬(Ⅵ)向铬(Ⅲ)的转化,修复结束时土壤中残留的铬90%以上为铬(Ⅲ);污染极其严重的铬渣山下土,由于含约28%的铬(Ⅲ),修复结束时铬(Ⅵ)的去除率达98%以上,而总铬去除率仅为75%-77%;阳极室附近土壤pH降低而阴极室附近土壤pH升高,处于两极中间位置的pH变化不大.电动力学与铁PRB原位联用方式能充分地利用这2种技术的优点,修复后,土壤任意位置的总铬去除率接近90%,阳极室附近尤为好于单一电动修复,对土壤pH的影响也较小.

废铁屑-H_2O_2法处理炼油厂含酚废水

用废铁屑作催化剂，Ｈ２Ｏ２作氧化剂，对炼厂汽提后含硫废水进行了除酚试验研究。考察了初始ｐＨ、Ｈ２Ｏ２投加量、废铁屑投加量对酚去除率的影响。对含酚量为３３１．５ｍｇ／Ｌ的废水，将其初始ｐＨ调至７．２，３０％Ｈ２Ｏ２的投加量为７．５ｍＬ／Ｌ，废铁屑的投加量为３～８ｇ／Ｌ，经２ｈ反应后，酚的脱除率可达９９．９％。

高浓度硫化染色废水处理新工艺研究

采用混凝沉淀－铁屑过滤－碱析组合工艺处理高浓度硫化染色废水。生产性试验结果表明；此工艺对硫化物、ＣＯＤ、ＢＯＤＳ和色度的去除率分别达９７．０％、８４．７％、８５．７％和９８．９％，处理后出水的各项污染指标均符合国家排放标准，具有系统运行稳定，操作管理简便，工程投资少，处理费用低等优点。

铁屑-粉煤灰微电解法处理DDNP废水

研究用铁屑-粉煤灰微电解法处理二硝基重氮酚生产废水,通过正交试验优化了处理条件,考察废水pH值、反应时间和反应温度等因素对处理效果的影响。对处理后废水的色度和CODcr进行了测试。结果表明,影响废水色度去除率和CODcr去除率的主要因素是废水的pH值。

铁炭联用修复硝酸盐污染地下水

针对地下水中硝酸盐污染,提出了废铁屑与颗粒活性炭联用,开展了修复模拟硝酸盐地下水的批试验研究。结果表明,铁炭总量为8.0～10.0 g时,残留NO3-为34.23～35.21 mg.L-1,此时介质用量为最佳值。介质粒径对NO3-去除效果的影响不明显。反应时间从1 h增至5 h,水相pH由初始值6.42增至7.09。中性时铁炭联用可以保持水相pH的稳定。在弱酸性条件下,只有特定的金属氧化物对NO3-去除具有促进效果,5种氧化物均导致水相中NO2-和NH4+增加。铁炭联用的修复机理包括化学还原、原电池反应、絮凝(共)沉淀、电泳富集和吸附,是一种经济有效修复硝酸盐地下水的方法。