纳米伊/蒙黏土对水体中重金属的吸附去除效果

为明确纳米伊/蒙黏土(下称伊/蒙黏土)作为修复材料在去除水体重金属方面的应用潜力,研究了伊/蒙黏土对水体中Ni2+、Cu2+和Cd2+的去除效果与吸附规律,并通过小麦水培试验分析伊/蒙黏土降低水体重金属在小麦地上部分的累积和缓解重金属对小麦的毒害效应等效果. 结果表明:伊/蒙黏土可以吸附去除水体中的Ni2+、Cu2+和Cd2+,当水体中ρ(Ni2+)、ρ(Cu2+)和ρ(Cd2+)分别为5、10、2 mg/L时,添加2%(以w计)的伊/蒙黏土对3种重金属的去除率均达到95%以上. 伊/蒙黏土对重金属的吸附等温线符合Langmuir方程,对Ni2+、Cu2+和Cd2+的理论最大吸附量分别为2.13、8.52和1.56 mg/g. 在培养液中添加2%伊/蒙黏土可降低小麦对Ni2+、Cu2+和Cd2+的累积富集,缓解重金属对小麦生长的毒害效应. 研究显示,纳米伊/蒙黏土可有效去除水体中的Ni2+、Cu2+和Cd2+,并缓解其对小麦的毒性,因此其在修复水体重金属污染、恢复水环境生态功能方面具有潜在的应用前景.      

Fe2+和Fe3+在4-氯酚光化学反应中性质的相似性

研究在光照条件下,２０ｍｇ／ｌ４－氯酚＋１ｍｇ／ＬＦｅ＾２＋（体系Ａ）和２０ｇ／Ｌ４－氯酚＋１ｍｇＦｅ＾３＋（体系Ｂ）中Ｆｅ＾２＋和Ｆｅ＾３＋的浓度变化,通过离子色谱手段,在体系Ａ中能够同时检测出Ｆｅ＾２＋,在体系Ｂ中亦能够同时检测到Ｆｅ＾２＋,故Ｆｅ＾２＋和Ｆｅ＾２＋在４－氯酚光化学反应中的性质,表现出相似性。     

Effect of heavy metals and phenol on bacterial decolourisation and COD reduction of sucrose-aspartic acid Maillard product

Melanodins are amino-carbonyl complex, predominantly present in sugarcane molasses based distillery wastewater as major source of colourant. The microbial decolourisation of melanoidin is a challenge due to its binding property with other co-pollutants of distillery waste. Results revealed that the presence of Zn2+ (2.00-20.00 mg/L) in melanoidin solution (1200 mg/L) stimulated the bacterial growth and sucrose-aspartic acid Maillard product (SAA) decolourisation as compared to control, while Fe 3+ and Mn2+ at the same concentration inhibited the process. However, the presence of phenol (100 mg/L) along with Zn2+ , Fe3+ and Mn2+ suppressed the bacterial growth, SAA decolourisation and MnP activity. The shrinkage and reduced number of bacterial cell count at higher concentration of heavy metals in presence of phenol was also observed under scanning electron microscope.     

Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals

A novel nanoadsorbent for the removal of heavy metal ions is reported.Cotton was first hydrolyzed to obtain cellulose nanocrystals(CNCs).CNCs were then chemically modified with succinic anhydride to obtain SCNCs.The sodic nanoadsorbent(NaSCNCs) was further prepared by treatment of SCNCs with saturated NaHCO 3 aqueous solution.Batch experiments were carried out with SCNCs and NaSCNCs for the removal of Pb 2+ and Cd 2+.The effects of contact time,pH,initial adsorption concentration,coexisting ions and the regeneration performance were investigated.Kinetic studies showed that the adsorption equilibrium time of Pb 2+ and Cd 2+ was reached within 150 min on SCNCs and 5 min on NaSCNCs.The adsorption capacities of Pb 2+ and Cd 2+ on SCNCs and NaSCNCs increased with increasing pH.The adsorption isotherm was well fitted by the Langmuir model.The maximum adsorption capacities of SCNCs and NaSCNCs for Pb 2+ and Cd 2+ were 367.6 mg/g,259.7 mg/g and 465.1 mg/g,344.8 mg/g,respectively.SCNCs and NaSCNCs showed high selectivity and interference resistance from coexisting ions for the adsorption of Pb 2+.NaSCNCs could be efficiently regenerated with a mild saturated NaCl solution with no loss of capacity after two recycles.The adsorption mechanisms of SCNCs and NaSCNCs were discussed.     

云南鹤庆西山岩溶地下水主要离子雨季和旱季对比及来源分析

鹤庆西山岩溶地下水是当地居民的主要生活用水来源,本文综合运用统计学分析方法对地下水主离子的雨季和旱季变化特征及其来源进行了研究。结果表明,研究区岩溶地下水主要补给来源为大气降水,TDS介于113.3~180.76mg/L属弱矿化度水,总硬度(Ca2++Mg2+)介于38~53 mg/L之间属于极软水。HCO-3和(Ca2++Mg2+)分别占主要阴阳离子的79.6%~95.5%和75%~94%,按照O.A.阿列金分类法研究区水质为HCO3-Ca·Mg型水。Ca2+、Mg2+、Cl-、SO2-4及HCO-3均未出现季节性变化,Na+与NO-3为丰水期枯水期,K+出现异常为丰水期枯水期。参照我国及世界卫生组织饮用水标准,锰矿黑龙潭泉受人为活动的影响较大,不宜长期饮用;其他地区主要离子浓度不会对人体产生危害。     

二硫代氨基甲酸盐絮凝处理模拟油田聚合物驱采油废水的效果研究

在碱性条件下,端氨基聚醚Jeffamine-T403与二硫化碳反应合成了二硫代氨基甲酸盐型絮凝剂DTC(T403).考察了DTC(T403)对模拟聚合物驱采油废水的絮凝除油性能,研究了DTC(T403)、水解聚丙烯酰胺(HPAM)、Fe2+和Fe3+的投加量以及pH值对除油效果的影响.结果发现,DTC(T403)与Fe2+络合形成的网状螯合物通过网捕作用取得良好的絮凝除油效果;HPAM的存在影响絮凝除油效果;在同时投加Fe2+和DTC(T403)且二者的投加量分别为10mg/L和25mg/L的条件下,HPAM含量在0～900mg/L范围和含油量约300mg/L的模拟水样经絮凝处理后其含油量均可降到10mg/L以下.DTC(T403)的絮凝除油效果受pH値的影响,在pH7.5条件下可取得良好的除油效果.DTC(T403)适用于含Fe2+的聚合物驱采油废水的处理.     

3类金属离子对活性污泥吸附水体腐殖酸的影响

研究了3类金属离子对活性污泥吸附水体腐殖酸效果的影响.结果表明,盐类金属离子(Na )、硬度金属离子(Ca2 、Mg2 )和水解金属离子(Al3 、Fe3 )均能在一定程度上提高吸附效率.作为活性污泥助凝剂,以大于10-2mol/L硬度离子的促进效果为好.加入10-2mol/L Ca2 、Mg2 48 h后溶液中的腐殖酸浓度分别为(0.64±0.17)mg/L和(2.32±0.40)mg/L,其去除率分别为98.4%和94.2%;当加入10-1mol/L Ca2 、Mg2 48 h后,其去除率均接近100%,而且Ca2 离子促进作用要优于Mg2 .盐类金属离子、硬度金属离子、水解金属离子提高活性污泥吸附腐殖酸的主要作用机理可能分别是压缩双电层、架桥作用、吸附共沉淀.同时,投加金属离子也可能使活性污泥上的吸附位性质改变或失效,对腐殖酸的吸附有一定的负面影响.     

铜和锌离子对真鲷幼鱼组织酶活性的影响

研究水中Ｃｕ＾２＋、Ｚｎ＾２＋对真鲷幼鱼组织ＣＡＴ、ＧＰＴ、胃蛋白酶活性的影响。结果表明：真鲷幼鱼暴露于不同浓度Ｃｕ＾２＋（０．５、０．７５、１．５ｍｇ／Ｌ）、Ｚｎ＾２＋（１、２、４ｍｇ／Ｌ）海水中４ｄ后,Ｃｕ＾２＋、Ｚｎ＾２＋对鳃,肝脏ＣＡＴ,胃蛋白酶有抑制作用。     

镉对大鼠肾皮质结合反应的影响

通过体内和体外试验分别研究了镉对肾皮质微粒体谷胱甘肽转移酶(GST)及游离肾近曲小管细胞中葡萄糖醛酸(GA)结合反应的影响.结果表明:(1)体外试验中,在10~(-7)—10~(-3)mol/L浓度范围内,镉可抑制肾皮质微粒休GST活力;(2)体内腹腔注射CdCl_2(2.4mg/kg,连续3天)后,大鼠肾皮质GST活力无明显改变;(3)按同样方式腹腔注射CdCl_2后,可降低游离肾近曲小管细胞中GA和7-羟基香豆素(7-HC)的结合反应;(4)体外试验中,低浓度镉(10~(-7)mol/L)可使肾皮质细胞中GA和7-HC的结合反应增强,而在10~(-6)—10~(-2)mol/L浓度范围内,镉可降低GA和7-HC的结合反应.     

Decontamination of alachlor herbicide wastewater by a continuous dosing mode ultrasound/Fe2+/H2O2 process

We used a ultrasound/Fe2+/H2O2 process in continuous dosing mode to degrade the alachlor.Experimental results indicated that lower pH levels enhanced the degradation and mineralization of alachlor. The maximum alachlor degradation(initial alachlor concentration of 50 mg/L) was as high as 100% at pH 3 with ultrasound of 100 Watts, 20 mg/L of Fe2+, 2 mg/min of H2O2 and 20℃ within60 min reaction combined with 46.8% total organic carbon removal. Higher reaction temperatures inhibited the degradation of alachlor. Adequate dosages of Fe2+and H2O2 in ultrasound/Fe2+/H2O2process not only enhance the degradation efficiency of alachlor but also save the operational cost than the sole ultrasound or Fenton process. A continuous dosing mode ultrasound/Fe2+/H2O2 process was proven as an effective method to degrade the alachlor.     

Mg2+ improves biomass production from soybean wastewater using purple non-sulfur bacteria

Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria (PNSB). This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg²⁺ under the light-anaerobic condition. Results showed that with the optimal Mg²⁺ dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L, and biomass yield also was improved by 60%. Chemical Oxygen Demand (COD) removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg²⁺ could promote the content of bacteriochlorophyll in photosynthesis because Mg²⁺ is the bacteriochlorophyll active center, and thus improved adenosine triphosphate (ATP) production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials (biomass yield) and COD removal, leading to more biomass production. With 10 mg/L Mg²⁺, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.     

Cadmium removal from wastewater by sponge iron sphere prepared by charcoal direct reduction

Sponge iron sphere (SIS), made of concentrated iron powder and possessed high activity and intension, was prepared through the process of palletizing, roasting and direct reduction by charcoal. The sponge iron sphere could remove most of Cd²⁺ from wastewater. The results showed the Cd²⁺ removal followed the first order reaction. Initial pH value played an important role in Cd²⁺ removal. With original initial pH, Cd²⁺ removal decreased to the minimum and then increased slightly with the rising of original concentration. The removal rate constant was ?0.1263 and ?0.0711 h^?1, respectively, under the Cd²⁺ concentration of 50 and 200 mg/L. When the initial pH was adjusted to 3.0, the removal rate constant could increase to ?9.896 and ?4.351 h^?1, respectively. The removal percentage almost reached to 100% when Cd²⁺ concentration was below 100 mg/L. While Cd²⁺ concentration was above 100 mg/L, Cd²⁺ removal percentage decreased slightly. In dynamic experiments, the column filled with sponge iron sphere exhibited favorable permeability. There was no sphere pulverization and conglutination between spheres. In contrast to the static state experiments, the Cd²⁺ removal percentage in dynamic state experiment was lower, and the removal Cd²⁺ quantity was 1.749 mg/g.     

Mechanism of combination membrane and electro-winning process on treatment and remediation of Cu^2＋ polluted water body

Mechanism of treatment and remediation of synthetic Cu2+ polluted water body by membrane and electro-winning combination process was investigated. The influences of electrolysis voltage, pH, and electrolysis time on the metal recovery efficiencies were studied. Relationship between trans-membrane pressure drop ( P), additions ratio, initial Cu2+ concentration on operating efficiency, stability of membrane and the possibility of water reuse were also investigated. The morphology of membrane and electrodes were observed using scanning electron microscopy (SEM), the composition of surface deposits was ascertained using combined energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectrophotometer. The results showed that using low pressure reverse osmosis (LPRO), Cu2+ concentration could increase from 20 to 100 mg/L or even higher in concentrated solutions and permeate water conductivity could be less than 20 μS/cm. The addition of sodium dodecy/sulfate sodium dodecyl sulfate improved Cu2+ removal efficiency, while EDTA had little side influence. In electro-reduction process, using plante electrode cell, Cu2+ concentration could be further reduced to 5 mg/L, and the average current efficiency ranged from 9% to 40%. Using 3D electrolysis treatment, Cu2+ concentration could be reduced to 0.5 mg/L with a current efficiency range 60%–70%.     

外源亚精胺缓解荇菜(Nymphoides peltatum)Cr6+毒害的生理研究

研究了不同浓度的Cr^6 胁迫下，荇菜叶中叶绿素含量、可溶性蛋白含量、O2^-产生速率、保护酶——超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的动态变化及外施亚精胺后对上述各指标的影响．结果表明：(1)单一Cr^6 处理下，叶绿素和可溶性蛋白含量在Cr^6 浓度为1mg／L时达到最大值，而后迅速下降；外施亚精胺(Spd)可显著提高二者的含量，延缓它们的下降速度．(2)单一Cr^6 处理下，SOD、POD、CAT活性分别在2、4、2mg／L Cr^6 处理下达到最大值．而后下降；外施亚精胺可提高这三种保护酶的活性，使其上升或稳定时期变长，从而降低O2^-等活性氧的产生速率．由此可见外源亚精胺可缓解Cr^6 对荇菜的胁迫效应．     

废水中GaAs、Ga3+、Ge4+对活性污泥脱氢酶的影响及其抑制动力学

以活性污泥脱氢酶的活性作为毒性指标,研究了半导体材料GaAs、Ga³⁺、Ge⁴⁺对活性污泥活性的抑制影响,并用Hg²⁺作为参比材料;同时对抑制动力学也作了初步研究。实验表明,GaAs、Ga³⁺、Ge⁴⁺及Hg²⁺的10％抑制浓度分别为45.00,371.63,0.13ppm/gMLSS,GaAs、Ga³⁺、Ge⁴⁺和Hg²     

微量金属元素投加量优化组合对污泥发酵产乙酸的影响

污泥厌氧发酵生产乙酸是实现污泥减量化和资源化的有效途径. 为了提高污泥中的ρ(乙酸),分别考察了Fe2+、Co2+、Cu2+、Zn2+和Mn2+5种微量金属元素的投加影响. 结果表明,5种微量元素都可以促进污泥中乙酸的产生,作用大小依次为Co2+>Mn2+>Fe2+> Zn2+>Cu2+. 但当Fe2+、Co2+、Cu2+、Zn2+和Mn2+投加量(以w计)分别超过0.100 0%、0.006 0%、0.002 0%、0.004 0%和0.100 0%时,ρ(乙酸)却明显下降. 分别选取Fe2+(0.040 0%~0.150 0%)、Co2+(0.002 0%~0.008 0%)、Cu2+(0.000 5%~0.006 0%)、Zn2+(0.000 5%~0.010 0%)和Mn2+(0.040 0%~0.150 0%)进行响应面条件优化试验. 在Fe2+、Mn2+投加量均为0.090 0%,Co2+、Zn2+投加量均为0.005 0%,Cu2+投加量为0.003 5%的组合优化条件下,ρ(乙酸)高达3 452 mg/L,比优化前提高了61.80%. 最优的微量元素投量组合条件下获得的试验结果与二次响应面回归模型预测值(3 475 mg/L)拟合率高达99.34%,表明所建立的回归模型可行.      

Cd2+ removal from wastewater by sulfate reducing bacteria with an anaerobic fluidized bed reactor

A process of treatment for containing Cd²⁺ wastewater by sulfate reducing bacteria with upflow anaerobic fluidized bed reactor has been studied. When the concentration of COD and Cd²⁺ in the influent were 270 5mg/L and 100mg/L respectively and hydraulic retention time was 4 hours, the removal rate of COD and Cd²⁺ were higher than 73 8% and 99 8% respectively. The reactor can treat as high as 1000mg/L of concentration of Cd²⁺ . The highest removal velocity rate of Cd²⁺ reached 2999 1mg/(L·d). And the possible relationship between sulfate reducing bacteria and methanogenic bacteria was discussed.     

巯基树脂的合成及对Hg2+的吸附特征

使用聚苯乙烯交联微球为前驱体,经一系列反应合成了一种苯环上含巯基的离子交换树脂(巯基树脂),研究了其对水中Hg2+的吸附特征. 巯基树脂的红外与元素分析结果表明,巯基官能团成功地嫁接到树脂表面,树脂中b(巯基)为2.89 mmol/g. pH对吸附的影响较大,当pH为1时,巯基树脂对Hg2+的吸附量很低,因此,可以用酸洗树脂使其再生. 当pH为2～7时,巯基树脂对Hg2+的吸附量相差不大. 巯基树脂对水中Hg2+的吸附等温线结果表明,温度的升高有利于吸附,吸附量高达14.500 mg/g,且符合Langmuir模型. Hg2+在巯基树脂上的吸附符合准二级动力学方程,对于初始ρ(Hg2+)为1 mg/L的溶液,吸附后最终ρ(Hg2+)可降到0.003 mg/L.      

Effects of Al3+ on the microstructure and bioflocculation of anoxic sludge

The aluminum ions generated from mining aluminum,electrolytic aluminum and the industrial production of aluminum-based coagulants(such as AlCl_3 and Al_2(SO_4)_3) enter sewage treatment plants and interact with activated sludges.An anaerobic/anoxic/oxic(A~2 O) process was used to reveal the effects of Al~(3+) on the pollutant removal efficiencies,bioflocculation and the micro structure of sludge.The results showed that a low concentration of Al~(3+) improved the pollutant removal efficiencies and increased the sludge particle size.However,a high concentration of Al~(3+) hindered microbial flocculation and reduced the pollutant removal efficiencies.With a 10 mg/L Al~(3+) addition,the chemical oxygen demand(COD),total nitrogen(TN) and NH_4~+-N increased by 3%,16% and 27%,and reached as high as 68%,60% and 87%,respectively.At the same time,the dehydrogenase activity,flocculation ability(FA) and contact angle of the sludge reached their maximum levels at 41.3 mg/L/hr,45% and 79.63°,respectively.The specific surface area of the sludge decreased to 7.084 m2/g and the sludge pore size distribution shifted to concentrate in the me soporous range.Most of Al~(3+) was adsorbed on the surface of sludge,changing the physicochemical properties and physical structure of the sludge.     

Simultaneous removal of Cu(II) and Cr(VI) by Mg–Al–Cl layered double hydroxide and mechanism insight

Mg–Al–Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20 mg/L) and Cr(VI) (40 mg/L) were completely removed within 30 min by Cl-LDH in a dosage of 2.0 g/L; the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200 mg/L) and Cr(VI) (400 mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg²⁺ and Al³⁺ in relevant solutions were monitored. To get the underlying mechanism, the Cl-LDH samples before and after adsorption were thoroughly characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On the basis of these analyses, a possible mechanism was proposed. The coadsorption process involves anion exchange of Cr(VI) with Cl⁻ in Cl-LDH interlayer, isomorphic substitution of Mg²⁺ with Cu²⁺, formation of Cu₂Cl(OH)₃ precipitation, and the adsorption of Cr(VI) by Cu₂Cl(OH)₃. This work provides a new insight into simultaneous removal of heavy metal cations and anions from wastewater by Cl-LDH.