Removal of Iron from Groundwater by Ozonation: The Response Surface Methodology for Parameter Optimization

This research studied the possibility of using ozone to remove iron from groundwater. The optimum conditions were investigated using a Box-Behnken experiment design with statistical analysis by response surface technique. The three parameters investigated, pH (6.0-8.0), hardness (300-500 mg/L as CaCO3) and removal time (10 to 60 min) were independent parameters of iron removal. Data was examined for optimal conditions and included main effects and their interactions. Analysis of variance indicated that the proposed quadratic model successfully interpreted the experimental data with a coefficient of determination (R2) of 98.83% and adjusted R2 of 96.72%. Through this model, it could predict the iron removal efficiency under variable conditions. Furthermore, the optimum conditions were pH 6.99, hardness of 300 mg/L as CaCO3, and 10 min of reaction time. The predicted iron removal efficiency obtained from the model under the optimum conditions was 99.00%. The experiment confirmed that the optimum condition which validated the model’s accuracy of iron removal efficiency was 98.45%. The results showed that ozone can remove iron from groundwater

Treatment of Iron from Groundwater by Ozonation: Influence of Hardness as a Scavenger

This study assesses the efficiency of using ozone technology to treat iron from groundwater while hardness acts as a radical scavenger. Batch experiments were conducted to determine the effects of initial pH 6, 7 and 8, and hardness of 300, 400 and 500 mg L-1 and kinetic analysis. The optimum conditions were found to be initial pH of 8 and hardness of 300 mg L-1. The removal efficiency of iron by ozonation was 99.97%, which was higher than that of air without ozone applied (83.67%). However, the presence of hardness and tert-butanol (TBA) had a negative effect on the oxidation of iron from groundwater. By increasing the carbonate hardness concentration, the oxidation rate of iron by ozone was reduced. The results of kinetic analyses indicated that the reactions of ozonation to remove iron from groundwater followed a pseudo-first order kinetic model with a rate constant of 0.0881 min-1, while air without ozone applied (aeration) was 0.0051 min-1. This finding suggests the potential use of ozone to remove iron from groundwater. Iron concentration from groundwater samples treated by ozonation have met the World Health Organization (WHO) guidelines (0.3 mg L-1)

Catalytic Ozonation using Iron-Doped Water Treatment Sludge as a Catalyst for Treatment of Phenol in Synthetic Wastewater

In this study, iron (Fe)-doped water treatment sludge, designated as Fe/WTS, was prepared by a hydrothermal method using phosphoric acid and impregnation with ferric nitrate. The results from X-ray diffraction (XRD) confirmed the presence of Fe loaded on the WTS support, while Brunauer-Emmett-Teller (BET) analysis indicated an increase of specific surface area of the WTS from 37.37 m2/g to 118.51 m2/g after acid modification. The Fe/WTS was successfully used as a catalyst in catalytic ozonation for degradation of phenol in synthetic wastewater. Factors affecting phenol removal efficiency including reaction time, pH, catalyst dosage, and Fe content were investigated. At the optimum condition, i.e., reaction time of 120 min, pH of 11, catalyst dosage of 1 g/L, and Fe content of 2% (w/w), the removal efficiency of phenol was 99.16% which was higher than that of sole ozonation (44.61%). The results of kinetic analyses indicated that the reactions of catalytic ozonation in the presence of Fe/WTS and WTS catalysts followed pseudo-first order kinetic model with rate constants of 0.0362 and 0.0065 min-1, respectively, while that of sole ozone was 0.0046 min-1. This finding presented the potential use of Fe/WTS as a novel catalyst for catalytic ozonation