Study of arsenic adsorption on Fe (hydr)oxides and Fe-Mn binary oxide and its application

随着我国沼气工程的迅猛发展，沼液量也大幅增加。由于沼气发酵的原料如畜禽类粪便等中含有大量的重金属，导致沼液中的重金属污染越来越严重，严重威胁着食品安全及人类健康。砷作为沼液中主要重金属污染物之一，且是一种高毒性的致癌物受到了广泛关注。铁锰氧化物在水体沉积物及土壤中分布广泛，且具有比表面积大和较高的氧化还原活性等特点使其在控制砷污染方面发挥着重要的作用。本课题以铁氧化物及铁锰复合氧化物为研究对象，研究三种铁氧化物（水铁矿、针铁矿及赤铁矿）在不同溶液pH条件下对As(V)的吸附机理以及铁锰复合氧化物对As(III)、As(V)的吸附氧化特性及共存物质对吸附效果的影响。本研究主要结论如下： （1）...With the rapid development of biogas project in china, biogas slurry also increases significantly. Since methane fermentation feedstock such as livestock and poultry contain a lot of heavy metals, which resulting from heavy metal pollution is getting worse and seriously threatening food safety and human health. Arsenic is one of the main heavy metal pollutants in biogas slurry and a highly toxic c...学位：工学硕士院系专业：环境与生态学院_环境工程学号：2262011115143

Adsorption behavior of Fe-Mn binary oxide towards As(Ⅲ) and As(Ⅴ) and its application in biogas slurry

研究了铁锰复合氧化物(fMbO)吸附去除AS(Ⅲ)、AS(V)的性能。结果表明fMbO对AS(Ⅲ)、AS(V)均具有较好的吸附能力,其饱和吸附量分别为111.10、71.40 Mg·g-1。AS(Ⅲ)和AS(V)是通过与fMbO表面的fE—OH基团进行交换并形成内层络合物的形式被fMbO吸附,且AS(Ⅲ)的吸附是吸附和氧化共同作用的结果。另外,沼液中共存离子对AS(Ⅲ)和AS(V)的吸附有不同的影响。zn2+能够增加fMbO对AS(Ⅲ)、AS(V)的吸附量,且增加幅度随着zn2+浓度的增加而增加;磷酸根对AS(Ⅲ)、AS(V)的吸附有明显的抑制作用,当磷与砷的分子摩尔比为1时,fMbO对AS(Ⅲ)、AS(V)的吸附量分别降低了34.70%、31.50%;但是有机物(腐殖酸、动物蛋白及尿素)对fMbO吸附AS(Ⅲ)、AS(V)的影响不大。利用fMbO对实际沼液中的砷进行吸附,结果表明砷的去除率平均达到65%左右,使吸附后某些沼液中砷的浓度达到生活饮用水标准和地表水排放标准。因此,将fMbO用于砷污染的沼液及水体的治理具有很好的应用前景。The adsorption behavior of arsenite(As(Ⅲ)) and arsenate(As(Ⅴ)) by Fe-Mn binary oxide(FMBO) was studied.The results indicated that FMBO had strong adsorption ability to both As(Ⅲ) and As(Ⅴ) and the maximum adsorption capacity was 111.10, 71.40 mg·g-1 respectively.As(Ⅲ) and As(Ⅴ) were adsorbed on FMBO surface through forming inner-sphere surface complexes by ligand exchange with hydroxyl groups, and As(Ⅲ) removal by FMBO was through an oxidation and adsorption combined process.In addition, the influences of co-existing substances generally present in biogas slurry were examined.Zinc ion could promote As(Ⅲ) and As(Ⅴ) adsorption on FMBO and the adsorption capacity increased with increasing zinc ion concentration.Phosphate had significant effect on As(Ⅲ) and As(Ⅴ) removal.When P/As ratio was equal to 1, the adsorption capacity of As(Ⅲ) and As(Ⅴ) was reduced by 34.70%, 31.50%, respectively.However, organics, such as humic acid, animal protein and carbamide had no significant effect on As(Ⅲ) and As(Ⅴ) removal.Moreover, FMBO as adsorbent for removal arsenic of actual biogas slurry was investigated.The average removal rate of arsenic of actual biogas slurry was about 65%, decreasing the arsenic concentration of some biogas slurry to the drinking water and surface water discharge standard.Therefore, FMBO could be an attractive adsorbent for both As(Ⅴ) and As(Ⅲ) removal from biogas slurry.国家重点基础研究发展计划项目(2013CB733505); 国家自然科学基金项目(21077086)~

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies