The conventionally employed zero-valent iron (Fe0) particles suffer a formation of surface oxides to lower their activity prior to use. During their using process for contaminant remediation, such oxide formation is also encountered, while the cumbersome handling of particles impedes the Fe0 recovery. To conquer the drawbacks, a Fe0 film was synthesized by electrodepositing ferrous ion cathodically on titanium (Ti) substrate to form a new Fe0/Ti system. X-ray diffraction (XRD) revealed that the freshly electrodeposited (FED) Fe0 film was free of oxides, which was attributed to the particularity of electrodeposition procedure. Reduction results of 10.0 mg/L chromium [Cr(VI)] indicated that the FED Fe0 film had higher activity than the oxide-covered counterpart. Further analysis of the pH-dependent Cr(VI) reduction reaction indicated that the Fe0/Ti system kept its activity and could be reused for further Cr(VI) reduction at pH 3.0 and 4.0, while it was inactivated at pH 5.0 and 7.0. Due to the easy handling of Fe0/Ti system, the inactivated Fe0 was recovered significantly through a cathodic reduction.

Thiswork investigated the effect of co-existing organic matters on aqueous Cr(VI) reduction by electrodeposited zero-valent iron (ED Fe0) at neutral pH. The ED Fe0 prepared in a solution containing mixture of saccharin, l-ascorbic acid and sodium dodecyl sulfate showed higher activity in reducing the aqueous Cr(VI) at neutral pH than that prepared without any organic presence. XRD and SEM indicated that the structure of ED Fe0 was significantly improved to nano-scale by the presence of organic mixture in the preparation solution. Further, the ED Fe0 activity in the Cr(VI) reduction at neutral pH was increased by the co-existence of citric acid or oxalic acid in the chromate solution. Electrochemical impedance spectroscopy (EIS) demonstrated that the corrosive current increased with the concentration of organic matter in the reaction solution. With the co-existing organic matters in the preparation solution, the ED Fe0 corroded more rapidly due to its nano-size, thus the Cr(VI) reduction by the ferrous iron was accelerated. With the co-existing organic matters in the reaction solution, the Cr(VI) reduction was accelerated by a Fe(II) complex as the main electron donor, and a prevention of the passivation due to the Fe(III) and Cr(III) complexes also accelerated the Cr(VI) reduction.

The photocatalytic (PC) degradation kinetics of sulfosalicylic acid (SSA) at different pH using TiO2 microspheres were elucidated by modeling. The resultant model had special consideration of adsorption and pH. The adsorption isotherms showed that the LC/MS2-identified intermediateswereweakly adsorbed on the TiO2 microspheres, thus their adsorptionwas neglected in the modeling. By contrast, the SSAwas significantly adsorbed, thus its adsorption retained as an item in the model. Consequently, a non-first-order modelwas obtained. Through the modeling, itwas elucidated that the reaction rate increased non-linearly with the SSA adsorption equilibrium constant. Meanwhile, it was elucidated that a pH increase favored the hydroxyl radical production to accelerate the SSA degradation, while impeded the SSA adsorption to slower it, hence a neutral pH caused the fastest SSA degradation.

The photocatalytic degradation of aniline was studied in annular photoreactor, with 2 6W (EmaxD365 nm) UV lamp as light source, borosilicate glass as wave filter and titanium dioxide immobilized on porous nickel as catalysts. Parameters such as the initial concentration, flow rate, initial pH, dissolved oxygen, electrolyte, hydrogen peroxide addition, temperature and external potential bias affecting the degradation rate of aniline were studied. The results showed that photocatalysis is an effective process for the degradation of aniline. The activated energy for the photocatalytic degradation of aniline is 6.13 kJ mol-1. The initial quantum yield is 1.89% for aniline 1.10×10-4 mol l-1. Total mineralization requires a much longer illumination time than the disappearance of anilines. The external potential bias can largely improve the efficiency of photocatalytic degradation of aniline. The degradation kinetic of aniline can be described by Langmuir-Hinshelwood equation.

a.c. impedance measurements are made on spiral-wound, size 4r5A, NirMH batteries, which are prepared by using direct-seal technology. Both the positive and the negative electrodes are fabricated by filling in a porous nickel substrate with the active materials. The main purpose of the investigation is to determine the causes. of the early cycling deterioration of this foam-type battery. The results demonstrate that the cycle-life curve can be divided into three parts. After little change in capacity and voltage, deterioration of the NirMH battery occurs as the voltage performance decreases. This is followed by a sharp decrease in both the discharge capacity and the voltage performance. The decrease in voltage performance is due to drying of the separator, which increases the total ohmic resistance of the battery, while the decrease of discharge capacity is due to an inactive surface that increases the charge-transfer resistance of the battery.