INVESTIGATION OF Pavonia urens AS A POTENTIAL BIOSORBENT IN HEAVY METAL REMOVALTHROUGH COMPLEXATION

Abstract

Metal ion-related environmental pollution poses a possible risk to human life. This is a result of various chemical wastes being released into the environment after being treated in an affordable and effective manner. Several herbs have been reported for use in heavy metals removal in wastewater. This study aimed at investigating the phytochemicals present and demonstrating the possible use of Pavonia urens leaves as adsorbent material through formation of a complex with selected metals zinc (Zn), copper (Cu) and nickel (Ni) from aquatic environment. The plant was collected from Uasin Gishu County and air dried before crushing. The ground powder was soaked in organic solvents (hexane, ethyl acetate, and acetone) of increasing polarity each for 48 hours followed by filtration and drying. The Four fractions obtained were labelled 1A, 2A, 3A and 4A. The GC-Mass spectrometer (MS) identified compounds with functional groups hydroxyl (OH), amine (-NH), and (-COOH). The ability of Pavoniaurens to complex with bimetallic ions in aqueous solution was also investigated using UV-VIS spectrometry. The interaction of these ions with functional groups revealed by UV-VIS analysis showed higher complexation for copper ions and zinc was the least. Plant material containing known concentration of the given metal ions was prepared for analysis at a fixed pH of 6, temperature of 298 K and 300 K, dosage of plant material 1 g and agitation speed at 125 rpm. One gram (1 g) of plant material was introduced to every 100 mL solution. Change in concentration was noted at intervals of 20 minutes using Atomic Absorption Spectrometer (AAS) until the rate of biosorption was constant. With regard to contact time and temperature, the biosorption of Cu (II), Ni (II), and Zn (II) ions on Pavonia urens leaves in a batch system was examined. The first step of the biosorption, which was rapid, happened in two stages, with Zn being the least biosorbed while Cu was the most. Compared to the Freundlich and Temkin isotherms, the Langmuir isotherm more closely matched the experimental results. The adsorption reactions were demonstrated to be spontaneous because ΔG 0< 0, feasible and exothermic (ΔHo < 0). P. urens contains bioactive species and is a viable alternative as an economical, environmentally friendly bio-sorbent that may successfully complex with metal pollutants in aqueous solution. As a result, P. urens merits exploration in the search for key chemicals in drug discovery as well as for use as an adsorbent.