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This research was conducted to study the adsorption of ammonium ions onto pumice as a natural and low-cost adsorbent. The physico-chemical properties of the pumice granular were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Modeling and optimization of a NH4+ sorption process was accomplished by varying four independent parameters (pumice dosage, initial ammonium ion concentration, mixing rate and contact time) using a central composite design (CCD) under response surface methodology (RSM). The optimum conditions for maximum removal of NH4+ (70.3%) were found to be 100 g, 20 mg/l, 300 rpm and 180 min, for pumice dosage, initial NH4+ ion concentration, mixing rate and contact time. It was found that the NH4+ adsorption on the pumice granular was dependent on adsorbent dosage and initial ammonium ion concentration. NH4+ was increased due to decrease the initial concentration of NH4 and increase the contact time, mixing rate and amount of adsorbent.

Aerobic treatment processes using attached media have been studied extensively to remove organic matter from wastewater and also denitrification process. The objective of this study was to assess the ability of down flow anaerobic up flow oxic submerged bio-film reactor (DAUOSBR) to remove phosphorus, nitrogen compounds, BOD5, COD, turbidity and total suspended solids from the Farabi Hospital wastewater. The present work involved designing and building a reactor loaded with down flow anaerobic up flow oxic submerged bio-film reactor, thereby a total of 450 samples were taken from the inlet and outlet of the treatment plant to evaluate the efficiency of the system. The results on stage of the operation (three parts) showed that the removal rate of COD, BOD5, TSS, Phosphorus and turbidity at the third stage and Nitrogen, TKN at the second zone were excellent. Comparatively the average removal efficiency of the mentioned parameters (except COD and TSS) showed a significant difference within three retention times (P<0.05). This system has exhibited high performance and capacity with regard to the removal of the selected parameters from hospital wastewater. Thus, the optimal times of 3.6 h and 1.4 h under aerobic and anaerobic conditions for the removal of ammonia nitrogen as well as 4 h and1. 5 h under aerobic and anaerobic conditions for the removal of phosphorus, organic matter, suspended solids and turbidity, were obtained, respectively. [ABSTRACT FROM AUTHOR]

Malachite green (MG) is one of the most used dyes in textile industries. The aim of this research work was to degrade MG, a model dye, using nickel-doped TiO2nanocatalysts. Nickel-doped TiO2nanocatalysts were fabricated under mild hydrothermal conditions (p = autogenous,T = 100°C, andt = 12 h). Nickel oxide andn-butylamine were used as dopant and surface modifier, respectively. The samples dried were characterized using powder X-ray diffraction, zeta potential, SEM, and electron diffraction X-ray analysis. The batch experiments of MG degradation were performed under UV light and sunlight irradiation. The effect of operational parameters including nanocatalyst dosage, pH, contact time, initial concentration of dye solution, and light source were investigated systematically. It was found that nickel-doped TiO2nanocatalysts had better solar degradation efficiency compared with bare TiO2under both UV light and sunlight irradiation. The optimum solar degradation efficiency for MG dye solution was achieved at pH 8, nanocatalyst dosage = 1.2 g/l, contact time = 120 min, and initial dye concentration = 250 mg/l. [ABSTRACT FROM PUBLISHER]