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
