H2O2水解壳聚糖的阻垢性能研究

筛选出了具有较好阻垢性能的H2O2水解壳聚糖,通过单因素试验考察了H2O2水解壳聚糖对模拟工业冷却水的阻垢效果以及壳聚糖浓度、Ca2+浓度、温度、pH、反应时间和浓缩倍数等对阻垢率的影响,并通过正交试验确定了最佳工艺条件.结果表明,H2O2水解壳聚糖对Ca2+成垢具有明显的阻碍效果;阻垢剂量8 mg/L,温度80℃,反应时间6 h,pH为7时,阻垢率达到97.4%.     

研究生论文摘要

本文在分析由虾蟹壳制备壳聚糖絮凝剂反应机理的基础上 ,通过试验分别确定了从蟹壳、虾壳制备壳聚糖絮凝剂的优化工艺参数 ;开展了产品在地表水、城市污水和染料配水、废水中的应用研究 ;确立了由虾壳制备壳聚糖絮凝剂的中试方案。对制备过程中的三个主要过程进行了清洁生产工艺设计 ,并用试验加以验证。由虾蟹壳制备壳聚糖絮凝剂主要有三步反应 :第一步主反应是盐酸使碳酸钙溶出 ,副反应是酸催化使得甲壳素糖酐键断裂 ;第二步主反应是热碱催化使蛋白质断裂成多肽和氨基酸溶出 ,副反应是甲壳素在热碱的作用下糖酐键断裂 ;第三步主反应是热浓…     

给水管网中硝化作用与金属离子释放交互作用研究进展

氯胺消毒给水管网中伴随着硝化作用的发生,会造成亚硝酸盐含量升高,消毒剂衰减加速,pH、溶解氧降低,异养菌过度繁殖以及管网中金属离子的释放。重点介绍了给水管网中硝化作用引起金属离子释放的成因,硝化作用对管网水质参数的变化和金属离子释放的影响,以及金属离子对硝化的反作用,并阐述了金属离子释放的控制方法。     

壳聚糖类絮凝剂及其在水处理中的应用

在对天然有机高分子絮凝剂———壳聚糖的理化性质及其对天然水和污水的絮凝进行研究的基础上，本文选择了壳聚糖作为新型有机絮凝剂制备的基质，研究了壳聚糖的提取和制备的工艺，对实验室制备的条件进行了优化，针对壳聚糖水溶性差和正电荷密度低的问题，探索了壳聚糖季铵盐和羧甲基衍生物的制备工艺，并对改性产品在污水处理中的应用加以研究，最后针对染料废水的絮凝脱色处理进行了复合絮凝剂研制和应用效果的初步探索。壳聚糖应用于给水处理时，与无机聚电解质复合可以改善絮体质量，与低分子量的无机盐复合可以提高浊度去除率，去除率…     

表面化学改性活性炭在水处理中的应用

介绍表面化学改性活性炭研究进展,针对其特点和改性方法作了系统描述.在此基础上,对其去除水中有机物、重金属离子、亚硝酸盐等污染物质做了简要说明.     

给水管网中管材对水质变化的影响研究

研究了给水管网中镀锌钢管、铝塑管等常用管材中水质变化的规律,得出了三种管材中游离氯和化合氯的衰减规律,分析了金属离子溶出的影响因素.发现三种管材中旧镀锌钢管的余氯衰减最快,新镀锌钢管比铝塑复合管余氯衰减要快,旧镀锌钢管中余氯衰减呈现一级动力学特征,新镀锌钢管和塑料管余氯衰减呈现零级动力学特征.随着管网水停留时间的增加,锌、铁等金属离子浓度增加,溶出铁的含量与浊度、色度呈现很好的线性相关关系.     

电镀废水外理工程设计实例

电镀废水水质复杂,含有多种金属离子,成分不易控制,适宜采用分质处理方式.介绍了广东江门某电镀厂废水处理工艺流程及相关技术参数和经济指标.     

阳离子型壳聚糖衍生物吸附性能研究

利用合成阳离子型壳聚糖衍生物通过镉离子的吸附试验，进行了改性壳聚糖动力吸附性能试验。经分析比较，结论认为：①改性的壳聚糖的吸附性能要好于壳聚糖。②在pH值较低时，改性壳聚糖的吸附量很小；随着pH值的增大，对镉离子的吸附量也逐渐增大；在pH值为7时，对镉离子的吸附最大，达到吸附平衡。     

壳聚糖-沸石复合体对铜绿微囊藻的去除效果

研究壳聚糖、沸石单独絮凝除藻以及壳聚糖沸石复合体对铜绿微囊藻去除效果。结果表明：单独使用壳聚糖,质量浓度在0.6～1.1 mg/L时,对铜绿微囊藻的去除率超过90％;单独使用沸石,沸石质量浓度小于500 mg/L时,对铜绿微囊藻的去除率低于40％。经壳聚糖包覆改性后,壳聚糖沸石复合体对铜绿微囊藻絮凝去除能力大幅提高。当壳聚糖质量浓度为0.5 mg/L,沸石质量浓度为6～14 mg/L时,壳聚糖沸石复合体对铜绿微囊藻的去除率达90％以上。壳聚糖沸石复合体适用的pH值范围在5～7之间。     

壳聚糖纱线对铜离子的吸附及抗菌性能的研究

以壳聚糖纤维为吸附原料,纺制成壳聚糖纱线,测试壳聚糖纱线的抗菌性能。探讨了壳聚糖纱线对铜离子吸附过程的动力学和热力学特性,铜离子吸附过程符合准二级动力学方程。结果显示,壳聚糖纱线对大肠杆菌和金黄色葡萄球菌的抑菌率达99%以上。可用Langmuir等温线拟合,纱线对铜离子的吸附是既有物理吸附又有化学吸附的自发放热反应,最佳吸附时间为90 min,达到吸附平衡时的时间为180 min,最佳的吸附pH为5,最适的吸附温度为25℃。在正交试验中,铜离子浓度对吸附量的影响最明显,溶液pH对吸附效率的影响最显著。最优的吸附组合为铜离子浓度为150 mg/L,pH为3,温度为15℃。对壳聚糖纱线吸附铜离子前后的材料用SEM、XRD、DSC、FT-IR进行了表征,分析其吸附机理。     

Membrane-flocculation-adsorption hybrid system in wastewater treatment: micro and nano size organic matter removal .

Cross flow microfiltration with in-line flocculation reduces the fouling of membranes thus leading to high quality product water. A detailed experimental study conducted with an artificial suspension (particle size distribution similar to that of surface water) revealed that the filtration rate can be increased by several times by adopting in-line flocculation. In-line flocculation-microfiltration is therefore an attractive technique to reduce internal clogging while improving the permeate flux significantly. A detailed ultrafiltration (UF) study was conducted with biologically treated sewage effluent with pretreatment by flocculation and powdered activated carbon adsorption. The TOC removal by the NTR 7410 UF membrane alone was 43.6%. The TOC removal increased significantly by the use of pretreatment: 69.3% by flocculation and 91% by flocculation followed by adsorption. The organic colloidal portion (between 3,500 dalton and 0.45 microm) in the biologically treated effluent was removed up to more than 65% by the pretreatment of flocculation. The molecular weight of the biologically treated effluent ranged from 250 to about 3,573 dalton with the highest fraction in the range of 250-845 dalton. By the incorporation of pretreatment, the majority of both large and small molecular weight organic matter was removed. This hybrid system led to practically no filtration flux decline in membrane filtration.     

Enhancement of removal efficiency of heavy metal ions by polyaniline deposition on electrospun polyacrylonitrile membranes

This paper describes the preparation of a membrane of polyacrylonitrile(PAN) and its corresponding membrane coated with polyaniline(PANI) for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb~(2+) and Cr_2 O_7~(2-).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC) conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1 202.53 mg/g,respectively.     

泥沙粒径对重金属污染物吸附影响的研究

本文系统研究了不同粒径泥沙颗粒对重金属污染物的吸附作用，粗细不同的泥沙对重金属污染物的吸附能力差异很大，因此研究天然河流泥沙吸附能力必须考虑泥沙组成的非均匀性和各级泥少的含量，度量泥少量粒吸附能力的标准主要是吸附活性组分的含量，而不仅是粒径大小。     

氨基功能化CaCO3粉末材料吸附重金属离子的研究

用直接沉淀法和包覆法相结合,制得氨基功能化CaCO3粉末材料,并对其作为某些重金属离子(Pb2+、Cu2+和Mn2+)的有效吸附剂进行表征及测定。X射线衍射(XRD)、能谱分析和扫描电子显微镜(SEM)证明该材料含有CaCO3,通过红外测定可知,功能性基团(-NH2)已成功包覆于CaCO3粉末材料上。氨基对重金属离子的吸附起主要作用,考察了吸附时间、重金属离子的初始浓度和溶液的pH值对吸附的影响。     

Flocculation mechanism by a novel combined aluminum-ferrous-starch flocculant (CAFS)

A combined flocculant (CAFS) was prepared with Al(2)(SO(4))(3)·18H(2)O, FeSO(4)·7H(2)O and starch. The flocculation mechanism of reactive brilliant red X-3B was studied. The results showed that CAFS was a cationic polymeric flocculant with high charge density, and its mesh starch chains grafted polyaluminum and polyferrous. At the preliminary stage, the main flocculation mechanism was adsorption and charge neutralization. At a later stage, the high molecular weight and flexible linear chains of CAFS initiated bridge-aggregation and sweep-flocculation. Moreover, the zeta potential and dynamic changes of flocs were closely related to flocculant dosages and the pH. The optimum dosage of CAFS and pH value were 0.990 mg/L and 5.0. Taken together, these results suggested CAFS as a novel flocculant in water treatment, with good results for the studied conditions.     

Heavy metal adsorption changes of EAF steel slag after phosphorus adsorption

A kind of electric arc furnace (EAF) steel slag was phosphated, and its isothermal and dynamic adsorptions of copper, cadmium, and lead ions were measured to determine if heavy metal adsorption changes after phosphorus adsorption. The surface area increased greatly after the slag was phosphated. Isothermal adsorption experiments showed that the theoretical Q(max) of the EAF steel slag on Cu(2+), Cd(2+), and Pb(2+) improved 59, 50, and 89% respectively after it was phosphated. Dynamic adsorption results showed that the greatest adsorption capacities of unit volume of Cu(2+), Cd(2+), and Pb(2+) were 2.2, 1.8, and 1.8 times that of the column packed with original EAF steel slag when the column was packed with phosphate EAF steel slag at the same heavy metal ion concentration. The breakthrough time, the exhaustion time and elution efficiency of the column also increased when the column was packed with phosphated EAF steel slag compared with that packed with original EAF steel slag. Phosphorus adsorption could further improve the heavy metal ion adsorption of the EAF steel slag.     

泥沙粒径对铜离子吸附贡献率的影响研究

含有重金属的工业废水排放到河道中,通过河道底泥的吸附作用,不断累积到底泥中,对环境和人类健康构成威胁。研究河涌底泥重金属吸附特性,对于解决重金属污染问题具有科学意义和现实价值。该文通过研究泥沙粒径对底泥吸附铜离子的影响规律,分析泥沙粒径对于铜离子的吸附量和吸附速率的影响特征。结果表明:在相同条件下,随着泥沙粒径的增大,泥沙对铜离子吸附速率的贡献率随之增大,粗颗粒泥沙的吸附速度要比细颗粒泥沙的迅速的多;而随着粒径的增大,泥沙对铜离子吸附量的贡献率随之减小,细颗粒泥沙的吸附量则远大于粗颗粒泥沙。     

不同粒径泥沙解吸重金属污染物静态试验研究

从吸附反应动力学方程和质量守恒方程出发，导得静态解吸试验中泥沙剩余吸附量和水相重金属浓度随时间变化的计算公式，并导得泥沙剩余平衡吸附量和水相平衡浓度随泥沙吸附－解吸的特性、泥沙初始重金属吸附量和泥沙浓度变化的计算公式。在此基础上，结合试验进一步研究了不同粒径泥沙解吸重金属污染物的能力。     

EXPERIMENTS ON SELF-PURIFICATION OF HEAVY METALPOLLUTANTS IN NATURAL RIVERS

1.INTRODUCTIONThemovementofwater,sedimentandpollutantsandtheinteractionamongtheminnaturalriversareverycomplicated.Movementofwater,sedimentandPOllutantsarerandom.ButfromastatisticalviewPOint,theirmovementfollowssomerules.Twokindsoftypicalcases,thatis,atributarywithheavymetalpollutantsjoiningamainstream,andanunPOllutedtributarywithmuchsedimententeringamainstreamcontaminatedbyheavymetals,arestudiedinthispaper.Besides,flowscenesinnaturalriversaredifferentindifferentseasons.InthenabPeriod,g…     

两种絮凝工艺去除污水中金属元素的对比试验

分别采用化学生物絮凝与化学絮凝两种工艺处理同一低浓度城市污水,对比分析污水中金属元素的去除效果。试验结果表明,在相同加药量的条件下,化学生物絮凝工艺在增加絮凝产物中铝元素含量的同时,对部分有害重金属的控制也优于化学絮凝工艺。但该工艺在处理高浓度污水时,处理效果会受重金属浓度的制约。