Study on polyepoxysuccinic acid reverse osmosis scale inhibitor

The effectiveness and applicability of polyepoxysuccinic acid (PESA) as a reverse osmosis (RO) scale inhibitor were studied using static and dynamic methods. In the static study, PESA performed very well in the treatment of water samples with various types of scale that commonly exist in RO water (i.e., CaCO₃, CaSO₄, BaSO₄, SrSO₄), showing an average scale inhibition ratio of above 90% at a dosage of 10 mg/L. SEM analysis showed a disordered CaCO₃ crystal in the presence of PESA, suggesting the scale-inhibiting mechanism. In the dynamic experiment, PESA also showed great performance in the treatment of 10 samples of synthetic tap water or sea water with different ion composition (i.e., Ca²⁺, HCO₃^?, Fe³⁺, Al³⁺). After one cycle (7 d) of RO treatment of each sample at full recycle operation mode under a constant pressure of 1×10⁶ Pa, the differences in water permeability and desalination ratio among samples are within 5%, suggesting that PESA is capable of treating waters of different quality, and has a strong resistance to ions that are harmful to scale inhibiting (i.e., Fe³⁺ and Al³⁺). All these results suggest that PESA should be an effective scale inhibitor that is applicable to RO treatment of waters with a wide range of ion compositions.     

Performance of landfill leachate treatment system with disc-tube reverse osmosis units

Reverse osmosis system with the disc-tube module (DT-RO) was applied to treat landfill leachate on full scale at the Changshengqiao Sanitary Landfill, Chongqing City, China. In the first six-mouth operation phase, the treatment performance of DT-RO system had been excellent and stable. The removal rate of chemical oxygen demand (COD), total organic carbon (TOC), electrical conductivity (EC), and ammonia nitrogen (NH₃-N) reached 99.2–99.7%, 99.2%, 99.6%, and over 98%, respectively. The rejection of Ca²⁺, Ba²⁺, and Mg²⁺ was over 99.9%, respectively. Suspended solid (SS) was not detected in product water. Effective methods had been adopted to control membrane fouling, of which chemical cleaning is of utmost importance to guarantee the long smooth operation of the DT-RO system. The DT-RO system is cleaned in turns with Cleaner A and Cleaner C. At present, the 1st stage cleaning cycle by Cleaner A and Cleaner C is conducted every 100 and 500 h, respectively, depending on raw the water quality.     

Low-pressure reverse osmosis as a process for treatment of anionic pollutants in water environment

The recent development of new generation Low-Pressure Reverse Osmosis (LPRO) or nanofiltration membranes have received attraction for application in the field of wastewater and water treatment through an increasingly stringent regulation for drinking purpose and water reclamation. In this research, the application on treatment of anionic pollutants (NO₃ ^-, NO₂ ^-, Cl^-, SO₄ ^2- &; H₂PO₄ ^-) was done under very much lower pressure range of operation (0.49 to less than 0.1 MPa) than any other previous research has done. Moreover, the extended Nernst-Planck equation was used for analysis of the experimental data by considering effective charge density of the membranes.     

Metal recovery in surface treatment units by using the 3PE reactor

Pollution from heavy metals arises mainly from industrial activities and, in this respect, it may be controlled and consequently reduced. The recovery of metals from industrial wastes is important, not only from an ecological point of view (toxicity), but also for economical reasons (recycling). At the present time, a large number of techniques are available to satisfy the stringent low concentration standards for waste water (Crine 1993; Verma et al. 1993). But for most of these techniques, it is not possible to have an immediate and total recycling of the recovered metal. With the development of the volumic electrodes, also called the flow-through porous electrodes, the electrochemical technique could be applied for the recovery of usable metals from effluents or dilute solutions and depollution. These electrodes are made up of a good conductor which has a porous structure through which the solution flows to be treated. In order to avoid disadvantages, such as the potential drop in the liquid phase and the problem of sealing, a new type of reactor called the Pulsating Porous Percolated Electrode (3PE) has been developed. This reactor eliminates the problem of plugging the particle bed by moving the matrix conductor during a fraction of time of the functioning of the reactor. This is done by using pulsed columns, which are largely used in different processes in chemical engineering. In this manner, one could expect to obtain the advantages of both the fixed and fluidized bed.     

金属尾矿制备生物陶粒的研究

阐述了利用江西某金属矿的尾矿、炉渣、粉煤灰制备一种多孔滤料陶粒的方法。实验结果表明：粒径5—30mm、粒子密度1．5-2．5g．／cm^3堆积密度0．65-1．3g／cm^3、比表面积7．2-13．5m^2／g、酸可溶率〈0．7％、筒压强度6．5-9．1MPa、吸水率0．1％～5％的陶粒质轻多孔,比表面积大,附着的微生物量大,孔隙率高,微生物挂膜快,老化生物膜易脱落。     

实验室重金属废水处理研究

根据实验室废水中Hg2+和Cr3污染特点,以硫酸亚铁、硫化钠作为还原剂,将废水中的Cr6+还原为Cr3+,Hg2+和Cr3+以沉淀的形式混凝去除。分别考察pH值、反应时间及还原剂投加量对两种重金属去除率的影响,结果表明过低的反应时间不利于Cr6+和Hg2+的去除,pH2.0时,Cr6+和Hg2+的还原效率较高,FeSO4和Na2S加量分别在1 000 mg/L和667 mg/L时,Cr6+和Hg2+具有较高的去除效率。利用正交实验对污染物去除条件进行优化,结果表明,两种无机还原剂投加比例对铬、汞两种重金属离子的去除率影响大,pH值次之,反应时间对去除率的影响最小,在pH为2.0、FeSO4和Na2S加量分别在1 000 mg/L和667 mg/L,反应时间为30 min时,废水中Hg2+和Cr6+的去除率最高,分别达到98.23%、95.97%,处理后废水达到国家污水排放标准。     

曲霉对水中重金属的吸附去除

利用2种曲霉A.sojae M146和A.oryzae M149的菌体，作为吸附剂对水中Pb^2＋和Cd^2 进行去除实验。结果表明，曲霉菌体的最佳培养时间为72h，吸附的最佳pH为5．5、温度为30℃、时间为1h。在最佳实验条件下，A.sojae M146对Pb^2 和Cd^2 的吸附率，分别为69．76％和72．28％；A.oryzae M149对Pb^2 和Cd^2 的吸附率，分别为60．64％和81．34％。使用稀碱溶液对曲霉菌体进行浸泡预处理后，可提高对重金属的吸附去除效果；而使用稀释、乙醇水溶液以及蒸馏水对菌体浸泡后，明显降低了重金属的去除效果。Na2CO3和EDTA溶液，可以有效地将重金属从曲霉体上解吸下来，从而达到重复利用菌体作为吸附剂的目的。     

某市工业源重金属污染源评价

针对某市工业源废水中6种重金属污染物产生现状,利用全国第一次污染源普查云南省数据,用等标污染负荷法计算出各种重金属污染负荷和负荷比,及每个工厂(地区)总的重金属污染负荷和负荷比,对某市工业废水重金属污染源进行评价,利用ARCGIS对该区域重金属产生量进行分析,明确重金属污染源空间分布规律,画出有重金属产生的企业的分布图,各种重金属产生空间分布图,和某市各乡镇的污染负荷等级图。结果表明该地区重金属污染源污染负荷的大小排列顺序是砷>汞>铅>六价铬>铬>镉。各企业的重金属源总污染负荷大小为化工厂>盐化昆明盐矿>盐化厂分厂>蓄电池厂>金属原料加工厂>电源厂>材料厂>废旧电瓶场>铸件厂。某市各镇的重金属污染源污染负荷大小排序为B镇>G镇>D镇>E镇。     

Phosphorus recovery from biogas fermentation liquid by Ca-Mg loaded biochar

Shortage in phosphorus(P) resources and P wastewater pollution is considered as a serious problem worldwide. The application of modified biochar for P recovery from wastewater and reuse of recovered P as agricultural fertilizer is a preferred process. This work aims to develop a calcium and magnesium loaded biochar(Ca–Mg/biochar) application for P recovery from biogas fermentation liquid. The physico-chemical characterization, adsorption efficiency, adsorption selectivity, and postsorption availability of Ca-Mg/biochar were investigated. The synthesized Ca–Mg/biochar was rich in organic functional groups and in Ca O and Mg O nanoparticles. With the increase in synthesis temperature, the yield decreased, C content increased, H content decreased, N content remained the same basically, and BET surface area increased. The P adsorption of Ca–Mg/biochar could be accelerated by nano-Ca O and nano-Mg O particles and reached equilibrium after 360 min.The process was endothermic, spontaneous, and showed an increase in the disorder of the solid–liquid interface. Moreover, it could be fitted by the Freundlich model. The maximum P adsorption amounts were 294.22, 315.33, and 326.63 mg/g. The P adsorption selectivity of Ca–Mg/biochar could not be significantly influenced by the typical p H level of biogas fermentation liquid. The nano-Ca O and nano-Mg O particles of Ca–Mg/biochar could reduce the negative interaction effects of coexisting ions. The P releasing amounts of postsorption Ca–Mg/biochar were in the order of Ca–Mg/B600 Ca–Mg/B450 Ca–Mg/B300. Results revealed that postsorption Ca–Mg/biochar can continually release P and is more suitable for an acid environment.     

从含银的废催化剂中回收白银

介绍了从含银的废催化剂中回收白银的一种新方法。采用氨浸A还原剂还原,浸出率98.5%,还原率99.9%,直接可获高纯度的银粉,金属银纯度可达99.9%。     

北京某道路外侧土壤重金属形态特征与污染评价

选取北京城区某主干道两侧土壤样品作为研究对象,测定其中Cr、Ni、Cu、Zn、Cd和Pb等重金属之总量,利用修正的BCR提取法分析各种重金属存在的形态。结果显示:Cr、Ni、Cu、Zn、Cd和Pb总量平均值分别超过北京地区背景值的1.51、3.84、1.78、2.33、13.92和1.32倍;Cr、Ni、Cu、Zn和Cd元素各形态分布情况为:残渣态>氧化态>酸提取态>还原态>水溶态;而Pb为残渣态>氧化态>还原态>酸提取态>水溶态。采用4种不同评价方法对研究区域土壤重金属污染现状进行评价。结果显示,基于总量评价方法中的地累积法得到的污染顺序为Cd>Ni>Zn>Cu>Cr>Pb,而潜在生态评价法得到的潜在污染顺序为:Cd>Ni>Cu>Pb>Cr>Zn;基于形态学的评价方法中RAC风险评价法得到生物可利用性顺序为:Ni>Cd>Zn>Cu>Pb>Cr;而次生相与原生相比值法得出:生物潜在可利用性依次是:Pb>Ni>Zn>Cd>Cu>Cr。     

松花江底泥沉积物中重金属释放影响因素的研究

以松花江哈尔滨段底泥沉积物为实验对象,研究松花江底泥沉积物中重金属的释放规律,使用循环槽(circulating flume)模拟松花江水力学条件,考察了重金属在上覆水和底泥中的沉积和释放。结果表明:松花江哈尔滨段底泥沉积物中重金属只有镉(Cd)超标,其它检测出重金属没有超标;随着温度升高,沉积物重金属溶出释放量也随之增加;重金属在酸性条件下的释放量明显高于碱性条件下的释放量;水体盐度升高,沉积物重金属的溶出释放也随之升高;水体扰动达到160 r/min时,重金属的释放达到最高值。     

从电子废弃物中提取贵金属的方法综述

对国内外电子废弃物的处理与回收技术进行了综合论述,并介绍了氨-硫代硫酸盐浸出法、生物法、液膜萃取法等现今较具前景的提取金属的新方法.提出了电子废弃物提取金属技术在今后的发展动向.     

乙酸-铁氧体共沉法处理城市污泥中的重金属

以天津东郊污水处理厂污泥为例,实验研究了乙酸-铁氧体共沉法去除城市污泥中重金属的技术条件和可行性。利用易获得、易降解的乙酸溶液,分析了乙酸浓度(H2O2含量2%)、pH值等与城市污泥中铜和锌去除效果之间的关系,表明当乙酸的浓度为2mol/L、反应时间4h、反应温度为室温、pH为4时,可以将95%以上的铜和锌淋滤去除,达到淋滤去除污泥中铜和锌的目的。采用改进铁氧体共沉淀法,用石灰乳溶液做中和剂,从污泥的乙酸-H2O2浸出液中去除含量超标的铜、锌、铬、镍、镉、铅。表明在pH为9、反应温度为室温、反应时间为1h、FeCl3和FeSO4初始浓度分别为0.1mol/L和0.05mol/L;Fe3+/Mn(+Cu、Zn、Ni、Cr、Cd、Pd离子总和)=10的最佳工艺条件下,铜、锌、铬、镍、镉、铅去除率为94%、98%、86%、92%、89%、99%;处理后的液体中铜、锌、铬、镍、镉、铅含量达到安全排放标准。     

辐射污染区土壤中耐重金属细菌的分离及其多样性

从新疆辐射污染区采集的40份土样中,通过重金属离子压力富集筛选,获得46株细菌。通过序列比对、聚类分析,确定46株菌中16株为芽孢杆菌属(Bacillus),13株类芽孢杆菌属(Paneibacillus),1株欧文菌属(Erwinia),10株假单孢菌属(Pseudomonas),1株不动杆菌属(Acinetobacter),1株克氏菌属(Kocuria),1株泛菌属(Pantoea),1株沙雷氏菌属(Serrolia),2株链霉菌属(Streptomyces)。通过进一步的重金属耐性分析,结果显示菌株对5种重金属离子的耐受程度总体呈现Pb2+>Zn2+>Co2+>Hg2+>Cu2+的趋势,其中对Pb2+的最大耐受性可达2 100 mg/L,对Zn2+的最大耐受性可达1 200 mg/L,对Co2+的最大耐受性可达1 000 mg/L,对Hg2+的最大耐受性可达500 mg/L,对Cu2+的最大耐受性可达450 mg/L。表明干旱荒漠土壤中具有较丰富的耐重金属细菌属种多样性,为耐辐射微生物在重金属污染治理方面的应用提供理论依据。     

Bioenergy recovery from landfill gas: A case study in China

Landfill gas (LFG) utilization which means a synergy between environmental protection and bioenergy recovery was investigated in this study. Pressure swing adsorption technology was used in LFG purification, and laboratory experiment, pilot-scale test, and on-site demonstration were carried out in Shenzhen, China. In the laboratory experiment, A-type carbon molecular sieve was selected as the adsorbent by comparison of several other adsorbents. The optimal adsorption pressure and adsorption time were 0.25 MPa and 2 min, respectively, under which the product generation rate was 4.5 m³/h and the methane concentration was above 90%. The process and optimization of the pilot-scale test were also reported in the paper. The product gas was of high quality compared with the National Standard of Compressed Natural Gas as Vehicle Fuel (GB18047-2000), when the air concentration in feed gas was under 10.96%. The demonstration project was composed of a collection system, production system, and utilization system. The drive performance, environmental protection performance, and economic feasibility of the product gas — as alternative fuel in passenger car, truck, and bulldozer—were tested, showing the feasibility technology for LFG utilization.     

温州市售贝类中重金属含量的分析与评价

调查了温州市售贝类中重金属(Cu、Pb、Cd、Cr、As、Hg)的含量,并采用《农产品安全质量无公害水产品安全要求》(GB 18406.4-2001)对检测结果进行评价。检测结果显示:温州市售贝类中Cu:1.23~10.67 mg/kg,Pb:ND~0.47 mg/kg,Cd:0.055~0.579 mg/kg,Cr:0.24~4.12mg/kg,As:0.39~2.95 mg/kg,Hg:0.014~0.036 mg/kg。市售贝类中Cu、Pb、Hg含量低于限量标准,但Cd、As、Cr有超标。说明温州市售贝类存在食用风险,应引起足够的重视。     

废旧锂离子二次电池回收有价金属工艺研究

本文对从废旧锂离子二次电池中回收有价金属的工艺进行了研究。采用解体分选出塑料外壳、铜铁连接件、石墨负极和正极；采用碱浸－酸溶－净化－沉钴工艺回收政极废料中的铝和钴。LiCoO2在硫酸、双氧水体系中的分解反应为：2LiCoO2 3H2SO4 H2O2→Li2SO4 2CoSO4 4H2O O2↑。用硫酸中和碱浸液中的铝，制取化学纯氢氧化铝，回收率为94．89％；以草酸钴的形式回收钴，产品达到Q／GGHO1－89标准，直收率94．23％。