Simultaneous removal of arsenite and fluoride via an integrated electro-oxidation and electrocoagulation process

An integrated electro-oxidation and electrocoagulation system was designed and used to remove As(III) and F⁻ ions from water simultaneously. Dimensionally stable anodes (DSA), Fe electrodes, and Al electrodes were combined into an electrochemical system. Two pieces of DSA electrodes were assigned as the outside of the Fe and Al electrodes and were directly connected to the power supply as anode and cathode, respectively. The Fe and Al ions were generated by electro-induced process simultaneously. Subsequently, hydroxides of Fe and Al were formed. Arsenic ions are mainly removed by iron hydroxides and F⁻ ions are mainly removed by the Al oxides. At the initial concentration of 1.0 mg L⁻¹, most of As(III) was transferred into As(V) within 40 min at current density of 4 mA cm⁻², whereas F⁻ ions can be efficiently removed simultaneously. The effect of the ratio of Fe and Al plate electrodes and current density on the removal of As(III) and F⁻ was investigated. With one piece of Fe plate electrode and three pieces of Al plate electrodes, it is observed that As(III) with concentration of 1 mg L⁻¹ and F⁻ with concentration of 4.5 mg L⁻¹ can be removed and their final concentrations were below the values of 10 μg L⁻¹ and 1.0 mg L⁻¹, respectively within 40 min. Removal efficiency of As(III) increases with the increase of solution pH. However, in the pH range of 6-7, removal efficiency of F⁻ is the largest.     

Electrochemical EDTA recycling with sacrificial Al anode for remediation of Pb contaminated soil

Recycling chelant is a precondition for cost-effective EDTA-based soil remediation. Extraction with EDTA removed 67.5% of Pb from the contaminated soil and yielded washing solution with 1535 mg L⁻¹ Pb and 33.4 mM EDTA. Electrochemical treatment of the washing solution using Al anode, current density 96 mA cm⁻² and pH 10 removed 90% of Pb from the solution (by electrodeposition on the stainless steel cathode) while the concentration of EDTA in the treated solution remained the same. The obtained data indicate that the Pb in the EDTA complex was replaced by electro-corroded Al after electro-reduction of the EDTA and subsequently removed from the solution. Additional soil extraction with the treated washing solution resulted in total removal of 87% of Pb from the contaminated soil. The recycled EDTA retained the Pb extraction potential through several steps of soil extraction and washing solution treatment, although part of the EDTA was lost by soil absorption.     

Electrochemical Detection of Pathogen Infection Using Cell Chip

The immobilized cell using self-assembled synthetic oligopeptide was applied to the electrochemical detection of pathogen infection. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for the immobilization of HeLa cell on gold (Au) substrate. Layer formation and immobilization of the cell were investigated with surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS). Experimental results showed that the thin film of cysteine-terminated synthetic oligopeptide was successfully fabricated and it could be applied for the immobilization of HeLa cells. The adhered living cell was exposed to E. coli O157:H7, which induced the change of SPR angle and electrochemical impedance signal. The proposed cell immobilization method using self-assembly technique can be applied to construct the cell microarray for on-site pathogen monitoring.     

Fabrication of electrochemically-modified BiVO4-MoS2-Co3O4composite film for bisphenol A degradation

A new electrochemically-modified BiVO₄-MoS₂-Co₃O₄ (represented as E-BiVO₄-MoS₂-Co₃O₄) thin film electrode was successfully synthesized for environmental application. MoS₂ and Co₃O₄ were grown on the surface of BiVO₄ to obtain BiVO₄-MoS₂-Co₃O₄. E-BiVO₄-MoS₂-Co₃O₄ film was achieved by further electrochemical treatment of BiVO₄-MoS₂-Co₃O₄. The as-prepared E-BiVO₄-MoS₂-Co₃O₄ exhibited significantly enhanced photoelectrocatalytic activity. The photocurrent density of E-BiVO₄-MoS₂-Co₃O₄ thin film is 6.6 times that of BiVO₄ under visible light irradiation. The degradation efficiency of E-BiVO₄-MoS₂-Co₃O₄ for bisphenol A pollutant was 81.56% in photoelectrochemical process. The pseudo-first order reaction rate constant of E-BiVO₄-MoS₂-Co₃O₄ film is 3.22 times higher than that of BiVO₄. And its reaction rate constant in photoelectrocatalytic process is 14.5 times or 2 times that in photocatalytic or electrocatalytic process, respectively. The improved performance of E-BiVO₄-MoS₂-Co₃O₄ was attributed to the synergetic effects of the reduction of interfacial charge transfer resistance, the formation of oxygen vacancies and sub-stoichiometric metal oxides and higher separation efficiency of photogenerated electron-hole pairs. E-BiVO₄-MoS₂-Co₃O₄ is a promising composite material for pollutants removal.     

Fast and Living Ring-Opening Polymerization of l-Lactide Initiated with In-situ–Generated Calcium Alkoxides

The ring-opening polymerization of l-lactide with calcium alkoxides generated in-situ from bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] and 2-propanol are presented. The polymerization in THF at room temperature proceeds rapidly and in a living manner, giving poly(l-lactide)s of controlled molecular weight, low polydispersity, and tailored end-functionalities. Kinetic studies show the absence of an induction period and a pseudo-first order rate constant of 6.41 L mol^–1 min^–1, which is significantly higher than for related Y₅(-O)(O ⁱ Pr)_13– or aluminum alkoxide-initiated polymerizations. The initiation involves a two-step process: (1) alcoholysis of bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] to give the corresponding calcium alkoxide and (2) ring-opening of l-lactide via acyl-oxygen cleavage and insertion into the calcium-alkoxide bond. In the presence of excess alcohol, fast and reversible exchange between free alcohol molecules and coordinated alkoxide ligands takes place. This allows tuning of the poly(l-lactide) molecular weight over a wide range.     

Species analysis methods for hydrolysis polymerization of aluminum

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DSA类电极催化降解硝基苯及其动力学研究

用新兴的电化学催化系统，采用特殊工艺自制的DSA类电有作为阳极，对模拟硝基苯废水进行降解处理。结果表明，最佳试验条件为：电流密度15mA/cm^21、Na2So4浓度5g/L、pH以中性和碱性较好。在适合的条件下。硝基苯废水CODcr去除率可达到90％以上，DSA类电极能有效地催化降解硝基苯。对试验结果进行的非线性最小二乘法分析表明，硝基苯在电化学催化系统中的降解过程符合一级反应模型，在硝基苯质量浓度200mg／L、pH11．0、Na2SO4浓度10g／L、电流密度15mA/cm62的试验条件下，CODcr去除速度常数为0．0395min^-1。     

APM对小麦根尖分生组织细胞异常有丝分裂的诱导

探讨了不同浓度（c／μmol．L－1）和不同处理时间（t／h）下APM对小麦根尖分生组织细胞有丝分裂的影响．实验结果表明，在c（APM）＝1～4μmol／L、处理t＜5h可明显提高有丝分裂指数，对前期和中期细胞分裂的促进作用更为明显；但c（APM）的增加与有丝分裂指数的提高无明显线型关系；APM可促使间期细胞微核形成、中期细胞染色体聚合现象和扰乱纺锤丝的功能．纺锤丝功能上的扰乱可引起细胞的“不均等分裂”和“多极化分裂”形成上述两种细胞异常有丝分裂的临界浓度和处理时间分别为c＝5μmol／L和t＞5h．     

不饱和聚酯树脂生产废水治理技术

不饱和聚酯树脂生产废水CODCr高达 10 0 0 0 0mg/L ,pH为 1— 2 ,且排放无规律 ,处理难度大。采用先对缩聚废水进行蒸馏浓缩 ,再真空泵废水混合调质、降温、缺氧水解后 ,经高效的好氧生物处理工艺 (HCR)处理后与低浓度的冲洗水、生活废水混合 ,进行低负荷的生物接触氧化处理 ,出水CODCr稳定在 10 0mg/L以下。     

卤代烃污染物的电化学氧化还原降解技术研究进展

开发新型的、无害化降解卤代烃污染物的处理方法已成为环境科学研究的难点和热点.有关卤代烃污染物的电化学氧化还原处理方法也逐渐引起了国际上的重视.在论述了电化学氧化和电化学还原两种方法处理卤代烃污染物的技术原理基础上,对电化学处理卤代烃污染物的研究现状进行了综述,着重介绍了目前应用该技术处理一些卤代烃污染物的电流效率以及电极研究的进展.探讨了电化学氧化还原降解技术在这一领域应用的可行性.