硫化亚铁处理含砷废水中砷的形态变化

本文对用硫化亚铁处理含砷废水时，在气相、液相和固相中砷的形态进行了研究结果表明，在气相中无ＡａＨ３，但在Ａｓ（Ｖ）废水的液相中有Ａｓ（Ｖ）和Ａｓ（Ⅲ）共同存在，在固相中有Ａｓ（０），ＦｅＡｓＯ４（ＦｅＡｓＯ３），Ａｓ２Ｓ３（Ａｓ２Ｓ５）和吸附砷，砷的形态变化表明，硫化亚铁处理含砷废水能取得良好的效果，是沉淀、沉淀转化、氧化还原、吸附共沉淀和中和五种反应共同作用的结果。     

硫化砷渣一步水热矿化成臭葱石和单质硫的研究

硫化物沉淀法是最常用的处理含砷废水的方法之一,但该方法会产生大量的无定形硫化砷渣,砷渣中的砷元素在微生物和pH值等环境因素的影响下,容易重新释放到环境中引起二次污染.因此本文选取硫化砷作为研究对象,借鉴含砷废水的处理思路,将硫化砷在氧化性条件下转化成化学性质和结构稳定的臭葱石,同时回收单质硫,单质硫的回收率为90％左右...     

尾砂除砷(Ⅲ)研究

本文对尾砂处理酸性含砷废水进行了研究,取得了良好的处理效果。     

正辛醇萃取苯酚稀溶液的特性研究

为探索工业含酚废水处理的适宜萃取剂，进行了正辛醇萃取苯酚稀溶液的实验研究，测定了不同pH值和苯酚初始浓度条件下的萃取平衡数据，萃残液CODCr值，分析了萃残液中CODCr值的来源。综合考虑萃取剂的萃取能力和产生的CODCr值，提出了酸性和中性溶液为正辛醇处理苯酚废水的适宜操作条件。以正辛醇为萃取剂对工业含酚废水进行了错流萃取实验，论证了其应用的可行性。     

腐植酸重金属废水净化剂对汞、镉、铅等金属离子的吸附能力

腐植酸重金属废水净化剂(简称腐植酸净化剂)性似弱酸型阳离子交换树脂,其主要工作功能团为羧基和酚羟基。吸附金属离子的主要反应有离子交换、络合和表面吸附等。 腐植酸净化剂对重金属离子只有吸附能力强和选择性吸附特点。对Hg~(2 )、Cd~(2 )、Pb~(2 )、Ni~(2 )等重金属离子的饱和吸附最可达180—420毫克/克。与732~#阳离子交换树脂相比,腐植酸净化剂在废水中Ca~(2 )、Mg~(2 )等干扰离子含量较高(1—5克/升)时,仍可从中有     

离子色谱测定三价砷和五价砷的研究

本文对抑制电导离子色谱法测定三价砷和五价砷进行考察,对测定的条件如标样的配制、淋洗液的选择、三价砷的氧化进行了讨论.并推荐了一种三价砷和五价砷的快速、分辨率好的方法,该方法可望对废水中的砷进行测定.     

活性碳去除过硫酸盐生产废水氧化性的研究

本文提出以活性碳处理含Ｓ２Ｏ８＾２－氧化物质废水的工艺路线，其特点较其它处理方法效率高、简便、成本低、易推广。经处理效果比较，发现在动态处理条件下，废水中氧化性物质的去除率达到９９．９％，其机理与活性碳起催化还原作用有关。     

砷在土壤中的吸附与释放的初步研究

本文对无机砷(As~(3+))和有机砷(苯砷酸)在土壤(0—23cm深)中的行为进行了试验,发现无机砷及有机砷在土壤中吸附1h以上才能达到平衡,体系的pH、砷化物浓度等对土壤吸附砷量影响较大。土壤对砷化物的吸附量随砷化物浓度加大而增加。对无机砷的最大吸附量在pH 6—8,对有机砷(苯砷酸)的最大吸附在pH4。无机砷的吸附开始受温度影响不大,50℃以后吸附量明显降低,对有机砷的吸附最大值在40℃左右。含砷废水中的砷在土壤中微生物作用下逐渐向大气扩散。释放速度在60d左右最大。通空气或氮气对砷的释放影响不明显。     

pH值和矿物成分对砷在红土中迁移的影响

研究了体系pH值和土壤矿物成分对贵州省安顺和遵义两个地区碳酸盐岩红土吸附砷的影响，探讨了红土对砷的吸附机理。研究发现：pH值是影响砷吸附的重要因素，一般来说，酸性环境（pH=4-7)有利于红土对砷的吸附，随着体系pH值的升高，红土对砷的吸附量逐渐降低；不同矿物成分的红土对砷的吸附性能差异很大；含针铁矿高的红土对砷的吸附量逐渐降低；不同矿物成分的红土对砷的吸附性能差异很大；含针铁矿高的红土对砷表现出良好的吸附性能。说明针铁矿与红土吸附砷有很大的正相关性。     

活性碳去除过硫酸盐生产废水中氧化性的研究

本文提出以活性碳处理含Ｓ２Ｏ２－８氧化性物质废水的工艺路线，其特点较其它处理方法效率高、简便、成本低、易推广。经处理效果比较，发现在动态条件下，废水中氧化性物质的去除率达到９．９％，其机理与活性碳起催化还原作用有关。     

PDMDAAC-阳离子膨润土的比表面积和吸蓝量的研究

以工业聚二甲基二烯丙基氯化铵和钠基膨润土为原料,采用水溶液吸附的方法和高温活化法合成阳离子膨润土复合材料,用次甲基蓝滴定法测定膨润土与阳离子膨润土的吸蓝量;用BET氮气吸附法测定比表面积,最后用阳离子膨润土处理染料废水．结果表明,与膨润土相比,阳离子膨润土的吸蓝量和比表面积有了不同程度的提高,随着吸附量的增加,吸蓝量和比表面积都增大,对废水的处理效果表明,阳离子膨润土的脱色率和COD的去除率都有较大的提高．     

Removal of arsenic by pilot-scale vertical flow constructed wetland

• VFCWs are effective for the treatment of arsenic-containing wastewater. • Arsenic removal did not affect the removal of nutrients, except for TP in CW500. • Arsenic removal was highest when the temperature peaked and the reed was in bloom. • Substrate accumulation contributed more to arsenic removal than plant absorption. Four pilot-scale Vertical Flow Constructed Wetlands (VFCWs) filled with gravel and planted with Phragmites australis were operated for seven months in the field to study the efficiency of arsenic removal in contaminated wastewater. The average arsenic removal efficiency by the VFCWs was 52.0%±20.2%, 52.9%±21.3%, and 40.3%±19.4% at the theoretical concentrations of 50 μg/L (CW50), 100 μg/L (CW100), and 500 μg/L (CW500) arsenic in the wastewater, respectively. The results also showed no significant differences in the removal efficiency for conventional contaminants (nitrogen, phosphorus, or chemical oxygen demand) between wastewater treatments that did or did not contain arsenic (P>0.05), except for phosphorus in CW500. The highest average monthly removal rate of arsenic occurred in August (55.9%–74.5%) and the lowest in November (7.8%–15.5%). The arsenic removal efficiency of each VFCW was positively correlated with temperature (P<0.05). Arsenic accumulated in both substrates and plants, with greater accumulation associated with increased arsenic concentrations in the influent. The maximum accumulated arsenic concentrations in the substrates and plants at the end of the experiment were 4.47 mg/kg and 281.9 mg/kg, respectively, both present in CW500. The translocation factor (TF) of arsenic in the reeds was less than 1, with most of the arsenic accumulating in the roots. The arsenic mass balance indicated that substrate accumulation contributed most to arsenic removal (19.9%–30.4%), with lower levels in plants (3.8%–9.5%). In summary, VFCWs are effective for the treatment of arsenic-containing wastewater.     

Human carcinogenesis by arsenic

Arsenic is one of the few human carcinogens for which there is not yet a reliable animal cancer model. As such, the classification of arsenic as a carcinogen is based upon data derived from human epidemiologic studies. Although the mechanisms of action of arsenic as a toxic agent have been known for many years, the inability to produce cancer with arsenic in laboratory animals has confounded the operational characterisation of arsenic as initiator, promoter, complete carcinogen, or cocarcinogen for humans. Arsenic is clearly a genotoxic agent that induces chromosomal aberrations, micronuclei and sister chromatid exchange in mammalian cells as well as neoplastically transforms Syrian hamster embryo cells; however, it is not a classical point mutagen. This paper reviews some of the scientifically based issues relating to arsenic and risk assessment.     

敌百虫萃取分离的研究

在考察敌百虫亲油性的基础上,本文对敌百虫稀溶液进行了溶剂萃取和络合萃取的研究。结果表于敌百虫的亲油一般,溶剂萃取分配系数较小,加入胺类络合剂提高了溶剂对敌百虫的萃取分配系数。     

黄河(内蒙古段)水体及悬浮物中砷的形态分布

以系统形态分析结合上浮水和悬浮物中砷的总量及形态分布特征,评价了黄河(内蒙古段)水体中砷的潜在危害程度.结果表明,水和悬浮物中砷的总含量出现了比较一致的沿河变化趋势,说明水中的砷主要是泥沙携带的砷,水中含砷量的高低取决于水中悬浮物即泥沙的含量.悬浮物中的砷以Ca-As为主,O-As次之,其它三种形态砷的含量均很低,与黄土中各形态砷的含量比较接近,进一步说明了黄河水体中的砷主要来源于自然界.     

Impact of roxarsone on the UASB reactor performance and its degradation

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, ROX) has been widely used for decades as an organoarsenic feed additive to control intestinal parasites and improve feed efficiency in animal production. However, most of the ROX is excreted into the manure, causing arsenic contamination in wastewater. The arsenic compounds are toxic to microorganisms, but the influence of continuous ROX loading on upflow anaerobic sludge blanket (UASB) reactor is still unknown. In this study, the impact of ROX and its degradation products on the performance of the UASB reactor and the degradation and speciation of ROX in the reactor were investigated. The UASB reactor (hydraulic retention time: 1.75 d) was operated using synthetic wastewater supplemented with ROX for a period of 260 days. With continuous ROX addition at 25.0 mg·L^–1, severe inhibition to methanogenic activity occurred after 87 days operation accompanied with an accumulation of volatile fatty acids (VFAs) and a decline in pH. The decrease of added ROX concentration to 13.2 mg·L^–1 did not mediate the inhibition. As(III), As (V), MMA(V), DMA(V), HAPA and an unknown arsenic compound were detected in the reactor, and a possible biotransformation pathway of ROX was proposed. Mass balance analysis of arsenic indicated that 60%–70% of the arsenic was discharged into the effluent, and 30%–40% was precipitated in the reactor. The results from this study suggest that we need to pay attention to the stability in the UASB reactors treating organoarsenic-contaminated manure and wastewater, and the effluent and sludge from the reactor to avoid diffusion of arsenic contamination.

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叶面喷施硒硅复合溶胶抑制水稻砷积累效应研究

砷是一种毒性较强的类金属元素,稻米砷污染是近年来环境科学关注的难点和热点问题。为了控制稻米对砷的吸收积累,利用水热合成法制备了一系列浓度硒掺杂硅复合溶胶。采用盆栽和大田试验结合的方法,研究了硒掺杂纳米硅溶胶对水稻（Oryza sativa L.）砷吸收积累的影响。结果显示,叶面喷施硒掺杂纳米硅溶胶可以有效缓解水稻砷毒害,增加稻米硒含量,抑制稻米砷积累。盆栽试验结果表明：叶面喷施质量分数1%的硒掺杂纳米硅溶胶（1%Se-Si处理）后,水稻籽粒干质量比对照增加了43.8%,砷含量下降了46%,硒含量由对照的0.050 mg·kg-1增加到0.272 mg·kg-1。且与喷施亚硒酸钠相比（1%Se处理）,喷施硒掺杂纳米硅溶胶更有利于水稻生长,抑制稻米砷积累。与喷施硒质量分数1%的亚硒酸钠（1%Se处理）相比,喷施质量分数1%的硒掺杂纳米硅溶胶（1%Se-Si处理）后,水稻籽粒干质量增加了65.4%,砷含量下降了33.1%。大田试验结果也表明：叶面喷施硒硅复合溶胶可以显著抑制稻米砷积累,且随着硒掺杂量的增加,稻米砷含量显著降低、硒含量显著增加;硒的最佳掺杂量质量分数为0.5%,叶面喷施这种硒掺杂硅溶胶,稻米总砷质量分数由对照的0.25 mg·kg-1下降到0.14 mg·kg-1,稻米中硒的质量分数为0.26 mg·kg-1,符合富硒大米标准。砷污染稻田上,叶面喷施硒硅复合溶胶不仅使稻米砷含量达标,而且可以生产出富硒大米。因此,叶面喷施硒硅复合溶胶可能是治理稻米砷污染的新途径。     

膜技术在电镀漂洗废水处理与回用中的应用

介绍了膜技术应用在电镀漂洗废水处理与回用中的运行效果及成本分析的实例。将连续膜过滤技术（CMF）用于反渗透的预处理,采用微滤膜在线连续反冲洗技术,成功解决了传统中空纤维膜易堵塞,不能连续工作的难题,保证了系统连续稳定运行。采用一级二段式RO（反渗透）系统,产水率65%,制备纯水180 m3/d,既提高了产水率也可满足生产用水要求。将抑菌剂、阻垢剂、在线监测和控制系统等关键技术,系统性、集成性引入连续微滤和反渗透装置,为其应用于废水脱盐深度处理提供支撑和保障。     

密切值法在污水土地处理工程选址中的应用

本文对密切值法在污水土地处理工程选址中的应用进行了探讨，通过实例分分析看出该方法科学可行且简易。