ABSTRACT
Coagulation with synthetic chemicals has been used to treat a wide range of industrial effluents. Herein, the unique characteristics of industrial effluents being detrimental to the environment warrants urgent resource-efficient and eco-friendly solutions. Therefore, the study investigated the use of two magnetized coagulants (chitosan magnetite (CF) and rice starch magnetite (RF)), prepared via co-precipitation in three different ratios (1:2, 1:1 and 2:1) of natural coagulants (chitosan or rice starch) and magnetite nanoparticles (F) as alternative coagulants to alum for the treatment of wastewater. A Brunauer-Emmett-Teller (BET) analyzer, an X-ray diffraction (XRD) analyzer, and energy-dispersive X-ray (EDX) spectroscopy were used to characterize the surface area, crystal structure, and elemental composition of the coagulants. The influences of settling time (10-60 min) on the reduction of turbidity, color, phosphate, and absorbance were studied. This was carried out with a jar test coupled with six beakers operated under coagulation conditions of rapid stirring (150 rpm) and gentle stirring (30 rpm). Wastewater with an initial concentration of 45.6 NTU turbidity, 315 Pt. Co color, 1.18 mg/L phosphate, 352 mg/L chemical oxygen demand (COD), and 73.4% absorbance was used. The RF with a ratio of 1:1 was found to be the best magnetized coagulant with over 80% contaminant removal and 90% absorbance. The treatability performance of RF (1:1) has clearly demonstrated that it is feasible for wastewater treatment.
ABSTRACT
The use of synthetic coagulants to reduce suspended particles from drinkable water and wastewater is prompting new issues because it poses many health and environmental risks. Hence, improving the coagulation process using sophisticated nanotechnology with a magnetic field (MF) for quick recoverability emerges as being useful. In this study, the effects of magnetite rice starch (MS) and aluminum sulfate (alum) were investigated at a constant dose (3 g or 3000 mg/L) using a Jar test (six beakers) as potential low-cost coagulants for industrial wastewater treatment. At a high magnification of 1000× and a surface pore size of 298 µm, scanning electron microscopy and energy dispersive X-ray (SEM/EDX) analyses were utilized to elucidate the morphology of the coagulants. Coagulation was performed at 150 rpm (quick mixing) for 2 min, and 30 rpm (slow mixing) for 15 min. Thereafter, samples were allowed to settle (10-60 min) with and without MF. The findings showed more than 65% contaminants removal (turbidity and TSS) and 30% chemical oxygen demand (COD) removal using alum while MS showed 80% contaminants removal (turbidity and TSS) and 50% COD removal. MS showed an increase of more than 3% in contaminants removal (COD, turbidity, and TSS) when exposed to MF. As a result, the use of MS together with MF in water and wastewater treatment is anticipated as an environmentally benign and effective coagulant.
