NITRATE REDUCTION USING SYNTHESIZED G--NZVI AND G--NZVI--CU PREPAREDFROM OPTIMIZED EXTRACTED POLYPHENOLS FROM SUGANDA LEAVES

Abstract

Polyphenols present in Suganda (Plectranthus amboinicus (Lour.) Spreng) extract can reduce the cationic iron to zero valent iron while simultaneously forming nanoparticles. The study involved the phenolic extraction at different solvent concentrations and temperatures. The synthesized Green--Nanoscale Zero Valent Iron (G--nZVI) and Green--Nanoscale Zero Valent Iron -- Copper Bimetal (G--nZVI--Cu) were used to reduce nitrate in water. Scanning Electron Microscopy -- Energy Dispersive X--ray (SEM--EDX) and X--ray Diffraction (XRD) are used to characterize the particles. It was found out that at 35°C and 90% ethanol, the highest phenolic content was obtained. The Analysis of Variance (ANOVA) results showed that the effect of temperature and solvent concentration is significant on the phenolic extraction with a probability value of < 0.0001. The SEM analysis showed that the particles have sizes ranging from 100-- 150 nm. The EDX analysis showed higher amounts of oxygen ranging from 50--60%, iron having 40--50% weight and copper with nearly 4--5% weight. The green synthesized particles are amorphous in structure, with no clear peak at 2θ = 45°. The synthesized particles were successfully used to reduce nitrate in water. Analysis showed that significant amount of nitrate was reduced after 60 minutes, having a removal efficiency of 84.36% and 85.81% for G--nZVI and G--nZVI--Cu, respectively. It was found out that ammonium and nitrogen gas were the main products of the reaction. The results show that G--nZVI and G--nZVI--Cu can be used for the remediation of nitrate in water due to its high removal efficiency.