CdS Nanoparticle Photocatalysis of the Chain Oxidation of Sulfite Ions by Molecular Oxygen

High photocatalytic activity was found for colloidal cadmium sulfide nanoparticles in the radical chain oxidation of sulfite ions by molecular oxygen in aqueous solution. The kinetics of this reaction was studied and a mechanism was proposed, which is in satisfactory accord with the experimental data.     

聚苯胺表面修饰芳纶浆粕及其纸基材料的导电性能

通过在芳纶浆粕(AP)表面修饰聚苯胺(PANI)制备了聚苯胺-芳纶浆粕(PANI-AP), 然后与碳纤维(CF)共混, 采用湿法抄纸技术制备导电性能优异的纸基材料(PANI-AP/CP). 对其形貌结构、 导电性能及PANI分布均匀性进行了表征, 并研究了环境湿度、 温度、 pH值及放置时间对PANI-AP/CP导电性能的影响. 研究结果表明, PANI-AP表面粗糙度增加, 结晶度增加, 出现含醌式结构的导电PANI的衍射峰, 说明PANI成功修饰于AP表面. 采用该方法制备的PANI-AP/CP导电性能与分布均匀性均得到提高, 相对于碳纤维纸基材(CP), PANI-AP/CP的电导率为3.937 S/cm, 导电性能提高153.5%. 与PANI原位生长于CP(AP/CP-PANI)相比, PANI-AP/CP的导电性能提高34.6%, 总色差值(DE)降低74.9%.     

Advantage of selective production of green rusts for Sb(V) removal in Fe(0) electrocoagulation

The removal efficiency of pollutants in Fe(0) electrocoagulation (EC) has been associated closely with the speciation of generated Fe(II)/Fe(III) oxides during this process, which is very complicated and can be affected by various factors. In this work, in-situ Raman, X-ray diffraction and some other techniques have been used to study the speciation of Fe under different conditions and to establish a relationship between Fe speciation and Sb(V) removal efficiency. Results indicated that concentration of dissolved oxygen (DO) is a key factor influencing Fe(0) EC. It was found that green rusts (GRs) were formed and were then transformed into magnetite at lower DO concentration, and Sb(V) removal efficiency reached 99.9% after 30 min of EC. In contrast, γ-FeOOH was formed at high DO concentration, and the removal efficiency of Sb(V) after 30 min of EC was only 72.8%. In the presence of sulfite and phosphate with low concentrations, GRs can be stabilized and benefit the removal of Sb(V). We believe this work will provide some new insights on the mechanism of Fe(0) EC and the effective removal of other pollutants during Fe(0) EC process.     

Chloro-propylene Sulfite as Electrolyte Additive for Li/S Batteries

Chloro-propylene sulfite (ClPS) was employed as electrolyte additive of Li/S batteries for the first time. Linear potential sweep test showed that the C1PS keeps high electrochemical stability even under the voltage of 5.0V. Being used as electrolyte additive in Li/S batteries, C1PS displayed an excellent property for self-discharge prohibition. With C1PS additive the Li/S cells' initial discharge capacity was 856.2 mAh·g-1 and 830.8 mAh·g-1 at the current density of 15 mA·g-1 and 30 mA·g-1, after 30 cycles the discharge capacities were contained at as high as 753.8 mAh·g-1 and 715.6 mAh·g-1. By means of infrared spectra, TG/DTA experiment and element content analysis the speculated reason of CIPS's novel function as additive was proposed.     

Electrochemical Properties of the Oxo‐Manganese‐Phenanthroline Complex Immobilized on Ion‐Exchange Polymeric Film and Its Application as Biomimetic Sensor for Sulfite Ions

A biomimetic sensor containing the oxo‐bridged dinuclear manganese‐phenanthroline complex incorporated into a cation‐exchange polymeric film deposited onto glassy carbon electrode for detection of sulfite was studied. Cyclic voltammetry at the modified electrode in universal buffer showed a two electron oxidation/reduction of the couple Mn^IV(μ‐O)₂Mn^IV/Mn^III(μ‐O)₂Mn^III. The sensor exhibited electrocatalytic property toward sulfite oxidation with a decrease of the overpotential of 450 mV compared with the glassy carbon electrode. A plot of the anodic current versus the sulfite concentration for potential fixed (+0.15 V vs. SCE) at the sensor was linear in the 4.99×10^?7 to 2.49×10^?6 mol L^?1 concentration range and the concentration limit was 1.33×10^?7 mol L^?1. The mediated mechanism was derived by Michaelis? Menten kinetics. The calculated kinetics values were Michaelis? Menten rate constant= =1.33 µmol L^?1, catalytic rate constant=6.06×10^?3 s^?1 and heterogeneous electro‐chemical rate constant=3.61×10^?5 cm s^?1.     

多相条件下亚硫酸镁非催化氧化反应动力学及机理

副产物的氧化回收利用是影响镁法脱硫工艺发展的关键.本文通过真空旋转蒸发的方式制备了高纯度的亚硫酸镁样品,并利用鼓泡式反应装置,研究了亚硫酸镁非催化氧化的反应动力学,考察了pH、氧分压、亚硫酸镁浓度、气体流量、温度等因素对亚硫酸镁氧化反应速率的影响,得到了各反应物的分级数及表观活化能.结合三相反应过程的数学模型推断出亚硫酸镁氧化的本征反应在慢反应区进行,且氧的传质扩散是总反应的速率控制步骤.研究结果为氧化回收镁法脱硫副产物提供了理论依据.     

Preparation and thermal reactivity of some rare earth and uranyl hydrazinesulfinates and sulfite hydrazinates

Hydrazinesulfinate and sulfite hydrazinate derivatives of rare earth elements of composition Ln(N₂H₃SOO)₃(H₂O) and Ln₂(SO₃)₃(N₂H₄)_x(H₂O)_y, respectively, where Ln=La, Ce, Pr, Nd and Sm, have been prepared and characterized by chemical analysis and infrared spectra. The uranyl complexes of the composition UO₂(N₂H₃SOO)₂, UO₂(N₂H₃SOO)₂(N₂H₄) and UO₂SO₃(N₂H₄)(H₂O) have also been prepared under different reaction conditions and studied by different physicochemical techniques. Thermal properties of all these complexes have been studied by thermogravimetry, and differential scanning calorimetry. The hydrazinesulfinate derivatives of rare earth elements undergo thermal decomposition in multisteps to give the respective metal sulfate as the residue. The other series of complexes, viz., rare earth sulfite hydrazinates gave a mixture of metal sulfate and metal oxide as the end products. However, all the uranyl complexes undergo decomposition in air to give UO₂SO₃ as the final product.     

Flow Injection Analysis of Hydrogen Peroxide,Sulfite, Formaldehyde and Hydroxymethanesulfonic Acid in Precipitation Samples

Abstract

Hydroxymethanesulfonic acid (HMSA), the reaction product of sulfite and formaldehyde plays an important part in the aqueous phase conversion of sulfite to sulfate. HMSA is fairly stable under acidic conditions and in presence of hydrogen peroxide. Sulfite is unstable under these conditions.

A flow injection set-up was developed, which allows the determination of H₂O₂, sulfite, formaldehyde and hydroxymethanesulfonic acid.

H₂O₂ analysis by amperometric detection offers the possibility of a simple, robust field instrument. The detection limit is 5μg/l and the method is linear up to 5mg/l.

Based on the 4,4-dithiodipyridine/sulfite reaction selective and sensitive spectrophotometric detections were developed for sulfite, formaldehyde and hydroxymethanesulfonic acid. The detection limit of these compounds is 50μg/l and the method is linear up to 5mg/l.

A large fraction of S(IV) is present as HMSA in fog, dew and precipitation samples in The Netherlands.