Removal Of Metals By Sorption With Metal Concentration Colour Sensitive Azotized Polyethylene Terephthalate Adsorbent

Abstract

This paper reports on the modification of polyethylene terephthalate (PET) by anchoring an azo group forming of a stable and colour sensitive absorbent capable of interacting with metal ions and removing them in aqueous media to alleviate heavy metal poisoning from its consumers. The modification was confirmed by FTIR (Fourier transform infrared) analysis and its metal adsorption property confirmed by FAAS (flame atomic absorption spectroscopic) analysis. The material exhibited colour variations upon interaction with copper, lead, cadmium and chromium ions which were the metal ions used in this study. This indicated when the material was exhausted thus signaling when to be regenerated. The modified material was then applied for their removal at their experimentally established parameters at a fixed temperature (25 °C). The optimum pH for the adsorption of copper, lead and chromium was 6.0 except for cadmium which was 5.5 as different pH values affects the stability of different complexes differently. The uptake of the metals was very fast as about 90% was adsorbed within the first 10 minutes of contact time. The sorption prescribed to second order kinetics thus bi molecular interaction of multilayer Langmuir adsorption. The adsorption capacities of copper, lead, cadmium and chromium were found to be 46.47, 33.65, 70.93 and 59.06 mg g-1 respectively. The study confirmed that adsorbent was regenerated by the use of 1.0 M nitric acid. This confirmed that azotized PET has potential application as a colour sensitive sorbent for the removal of heavy metal from water