The selective sorption of pentachlorophenol (PCP) in a multiple solute system provides the possibility of using the cetyltrimethylammonium bromide (CTMAB)/bentonite one-step process as a promising technique for hydrophobic organics removal from wastewater. The PCP sorption mechanism, especially the effects of coexisting solutes, was studied. Compared to raw bentonite and conventional CTMAB modified organobentonite, the one-step process exhibited higher PCP removal efficiency. In a single solute system, the PCP sorption isotherm implied that the dominating sorption mechanism is a partition mechanism. The logarithms of sorption coefficients (Kd) for different organics are linearly related to the logarithm of their octanol–water partition coefficients (Kow). In a multiple solutes system, phenol and 2,4-dichlorophenol (2,4-DCP) could effectively enhance PCP sorption. The PCP sorption coefficient increases in the order: PCP/phenol < PCP/2,4-DCP < PCP/phenol/2,4-DCP. The PCP sorption enhancement is likely resulted from the interlayer space expansion and the organic carbon content increase. On the basis of the comparison between the single and the multiple solute systems, phenol and 2,4-DCP sorption coefficients decrease in the order: Kd of a single solute system > Kd of a binary solute system > Kd of a ternary solute system, and no enhancement for phenol and 2,4-DCP sorption was observed.

Atmospheric water surface discharge is a promising method for water treatment. The selection of discharge gap distance must take a pair of conflicting aspects into account: the chemical efficiency grows as the discharge gap distance decreases, while the spark breakdown voltage decreases as the gap distance decreases. To raise the spark breakdown voltage and the chemical efficiency of atmospheric pressure water surface discharge, resistive barrier discharge is introduced in this paper. Both the high voltage electrode and the ground electrode are suspended above water surface to form an electrode-water-electrode discharge system. The water layer plays the role of a resistive barrier which inhibits the growth rate of discharge current as voltage increases. Experiments conducted at different discharge gap distances and water conductivities indicate that both the spark breakdown voltage and the chemical efficiency are remarkably raised in comparison with traditional water surface discharge. After parameter optimization, the discharge reactor is scaled up with activated carbon fiber electrodes and advantages of water resistive barrier discharge are kept.

Seawater flue gas desulfurization (SFGD) is a promising process for coal-burning power plants located along the coast. The aim of this work was to study the seawater outflow characteristics, especially the relationship between absorbed S(IV) and pH in the SFGD process. The equilibrium concentration of SO2 in seawater was studied under different seawater usages and SO2 concentrations in the flue gas. The experimental results showed that approximately 25% of absorbed S(IV) was oxidized to S(VI) by surplus oxygen in the flue gas during the absorption process. An equilibrium model was established to describe the relationship between absorbed SO2 and pH. The integral desulfurization efficiency of the absorption system was analyzed, and the results showed that desulfurization efficiency can reach up to 90%.

In this paper, the conversion of methane to methanol on CuO/Al2O3 and Mo–CuO/Al2O3 catalysts in a plasma reactor was tested. A comparison between catalytic and plasma-catalytic systems had been made in tested temperature range of 50–300°C. Experimental results showed that plasma-catalytic system demonstrated a much better methane conversion than catalytic system in tested temperature range and Mo–CuO/Al2O3 revealed a higher catalytic activity than CuO/Al2O3 for methanol synthesis. Furthermore, an Arrhenius plot was made in order to deduce the mechanism of plasma activation, which revealed that the presence of plasma decreased the activation energy for both catalysts. In the case of Mo-CuO/Al2O3 catalyst, the enhanced activity for methanol synthesis was assumed due to the oxygen vacancies on Mo–CuO/Al2O3 catalyst, which can utilize plasma-induced species to improve the catalytic efficiency.

For seawater flue gas desulfurization (SWFGD), oxidation of S(IV) to S(VI) in the effluent of the gas desulfurization (FGD) system is very critical for its industrial application, because the additional S(IV) results in high chemical oxygen demand (COD) value. This paper reports a novel pulsed corona discharge oxidation process to convert S(IV) to S(VI) by use of a cylindrical wetted-wall pulsed high voltage reactor. Several important parameters, including pH values, flow rate of the solution, voltage, electrode radius and the length of the plasma region, were investigated for S(IV) oxidation and energy efficiency (G) of the process. After discharge for 12 min, with the electrode radius of 8 mm, pH value of 3, flow rate of 40 L h−1, more than 95% of S(IV) was oxidized and the energy efficiency was about 5.8 × 10−9 mol J−1. Compared with the traditional air oxidation process, the plasma-induced oxidation is a promising and attractive technology for the SWFGD system.