Studies on the Adsorption Efficiency of Activated Carbon for Pesticide Vapour: Brief Overview

Chlorpyrifos pesticides are endocrine disruptors, inhibitors of acetyl cholinesterase, used to control
pests and prime contributors to indoor pollution in retail stores. Seven selected locally sourced
adsorbents; Bone charcoal (BCA), corncobs, cotton seed, kokoli, sawdust, coconut shell (CSA) and
Muruchi were evaluated. Only BCA and CSA shows peaks and were further examined at adsorptive
temperatures of 283, 293, 303 and 313K. Adsorbents physical properties that is, micro pore surface
area, total pore volume; micro pore volume, particle density and true density were measured and
compared. Results from gas chromatography and surface characterization revealed that the
adsorptive capacities of carbon (CSA) at various temperatures were higher than that of carbon (BCA).
The plots of Langmuir and Freundlich Isotherms were well fitted by the measured adsorption data.
The parameters of adsorption equation for both Langmuir and Freundlich were determined for the two
adsorbents, which indicates increased values of adsorptive capacity at low temperature and
decreases at high temperature. This study shows that activated carbon made from coconut shell has
high surface area, micro porous structure, high degree of surface reactivity and higher heterogeneous
properties that suggest it to be a better adsorbent sufficient for the adsorption of chlorpyrifos vapour in
an indoor environment.