Abdul Raman Abdul Aziz

Recent advances and prospects of catalytic advanced oxidation process in treating textile effluents

Abstract In the past few years, there have been many researches on the use of different types of homogenous catalyst for the degradation of textile wastewater in conventional advanced oxidation processes (AOPs). However, homogenous AOPs suffer from few limitations, including large consumption of chemicals, acidic pH, high cost of hydrogen peroxide, generation of iron sludge, and necessity of post-treatment. Therefore, recently, there have been more researches that focus on improving the performance of conventional AOPs using heterogeneous catalysts such as titanium dioxide, nanomaterials, metal oxides, zeolite, hematite, goethite, magnetite, and activated carbon (AC). Besides, different supports such as AC that have been incorporated with transition metals and clays have been proven to have excellent catalytic activity in AOPs. This paper presents a comprehensive review of advances and prospects of catalytic AOPs for the decontamination of a wide range of synthetic and real textile wastewater. This review provides an up-to-date critical review of the information on the degradation of various textile dyes by a wide range of heterogeneous catalysts and adsorbents. The future challenges of AOPs, including chemical consumption, toxicity assessment, reactor design, and limitation of catalysts, are discussed in this paper. In addition, this paper also discusses the presence of ions, generation of by-products, and industrial applications of AOPs. Special emphasis is given to recent studies and large-scale combination of AOPs for wastewater treatment. This review paper concludes that more studies are needed for the kinetics, reactor design, and modeling of hybrid AOPs and the production of their corresponding intermediate products and secondary pollutants. A better economic model should also be developed to predict the cost of AOPs, as the treatment cost varies with dyes and textile effluents.

Degradation performance and cost implication of UV-integrated advanced oxidation processes for wastewater treatments

Abstract Advanced oxidation processes (AOPs) are commonly used for treating recalcitrant wastewater with varying degree of efficiency, depending on several operating parameters. In this review, a comparative study among selected AOPs integrated with ultraviolet (UV) (UV/Fenton, UV/H2O2, UV/O3, UV/TiO2, UV/persulfate, UV/H2O2/O3, and UV/TiO2/H2O2) was conducted. The cost implication, changes in kinetics, changes in reaction rates, and effects of various parameters such as type of contaminants, pH, catalyst loading concentration of oxidants, and type of UV light are explained and concluded in this paper. From this review, it is concluded that UV-integrated AOPs are efficient for wastewater treatment. However, a few aspects must be considered including process scale-up, kinetics of combined processes, reactor configuration, modeling of a system, and optimization of operating parameters to enhance the process efficiency.

Sono assisted electrocoagulation process for the removal of pollutant from pulp and paper industry effluent

In the present work, the efficiency of the sonication, electrocoagulation, and sono-electrocoagulation process for removal of pollutants from the industrial effluent of the pulp and paper industry was compared. The experimental results showed that the sono-electrocoagulation process yielded higher pollutant removal percentage compared to the sonication and electrocoagulation process alone. The effect of the operating parameters in the sono-electrocoagulation process such as electrolyte concentration (1–5xa0g/L), current density (1–5xa0A/dm2), effluent pH (3–11), COD concentration (1500–6000xa0mg/L), inter-electrode distance (1–3xa0cm), and electrode combination (Fe and Al) on the color removal, COD removal, and power consumption were studied. The maximum color and COD removal percentages of 100 and 95xa0%, respectively, were obtained at the current density of 4xa0A/dm2, electrolyte concentration of 4xa0g/L, effluent pH of 7, COD concentration of 3000xa0mg/L, electrode combination of Fe/Fe, inter-electrode distance of 1xa0cm, and reaction time of 4xa0h, respectively. The color and COD removal percentages were analyzed by using an UV/Vis spectrophotometer and closed reflux method. The results showed that the sono-electrocoagulation process could be used as an efficient and environmental friendly technique for complete pollutant removal.

Removal of pollutants with determination of power consumption from landfill leachate wastewater using an electrocoagulation process: optimization using response surface methodology (RSM)

Treatment of landfill leachate wastewater by electrocoagulation process using an aluminium electrode was investigated in a batch electrochemical cell reactor. Response surface methodology based on central composite design was used to optimize the operating parameters for the removal of % color and % total organic carbon (TOC) together with power consumption from landfill leachate. Effects of three important independent parameters such as current density (X1), inter-electrode distance (X2) and solution pH (X3) of the landfill leachate sample on the % color and % TOC removal with power consumption were investigated. A quadratic model was used to predict the % color and % TOC removal with power consumption in different experimental conditions. The significance of each independent variable was calculated by analysis of variance. In order to achieve the maximum % color and % TOC removal with minimum of power consumption, the optimum conditions were about current density (X1)—5.25xa0A/dm2, inter-electrode distance (X2)—1xa0cm and initial solution of effluent pH (X3)—7.83, with the yield of color removal of 74.57%, and TOC removal of 51.75% with the power consumption of 14.80xa0kWh/m3. Electrocoagulation process could be applied to remove pollutants from industrial effluents and wastewater.

Liquid-liquid mass transfer studies in various stirred vessel designs

Abstract A general review on correlations to evaluate mass transfer coefficients in liquid-liquid was conducted in this work. The mass transfer models can be classified into continuous and dispersed phase coefficients. The effects of drop size and interfacial area on mass transfer coefficient were investigated briefly. Published experimental results for both continuous and dispersed phase mass transfer coefficients through different hydrodynamic conditions were considered and the results were compared. The suitability and drawbacks of these correlations depend on the operating conditions and hydrodynamics. Although the results of these models are reasonably acceptable, they could not properly predict the experimental results over a wide range of designs and operating conditions. Therefore, proper understanding of various factors affecting mass transfer coefficient needs to be further extended.