Pesticides abatement using activated carbon produced from a mixture of synthetic polymers by chemical activation with KOH and K2CO3

Abstract

Highly efficient low cost carbon adsorbents were prepared from synthetic polymers mixture, such as polyethyleneterephthalate (PET) and polyacrylonitrile (PAN), by chemical activation, with potassium hydroxide or potassium carbonate, at 1073 K. Mixtures polymers carbon activation is more effective with KOH than with K2CO3, since the apparent surface area and the micropore volume were always higher on those prepared with KOH. The activated carbons (ACs) obtained presented a high thermal stability, a basic character and a very high apparent surface area (between 1206 and 2828 m2 g-1), micropore volume (between 0.35 and 1.38 cm3 g-1), with mean pore sizes ranging the supermicropores region. These ACs were successfully tested on 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA) removals from the liquid phase. The results achieved are very promising, as the adsorption capacity of these AC is higher than that obtained with commercial AC used for this end.

Current State of Porous Carbon for Wastewater Treatment

“…Thus, the sodium hydroxide appeared to be more reactive, which resulted in the micropores fusing to form mesopores [135,145,193,204]. Indeed, several studies have reported that potassium hydroxide is an activator that promotes the formation of activated carbon with a microporous structure [166,167,183,206,221]. However, some authors obtained a mesoporous structure by activation with potassium hydroxide [134].…”

“…These properties with the conditions of application determine the applicability of the activated carbon. Large-pore activated carbon is effectively used for the adsorption of large pollutants and vice versa [135,179,204,206].…”

“…Da Paixao Cansado et al [206] did a comparative study of the adsorption of pesticides on chemically prepared activated carbon involving K 2 CO 3 and KOH. The aim was to obtain activated carbon from polymer waste (Polyacrylonitrile (PAN) and Polyethyleneterephthalate (PET)) and to determine their main characteristics, namely the characterization of their porosity, their functional groups on the surface, and their adsorption capacities for 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D).…”

“…The aim was to obtain activated carbon from polymer waste (Polyacrylonitrile (PAN) and Polyethyleneterephthalate (PET)) and to determine their main characteristics, namely the characterization of their porosity, their functional groups on the surface, and their adsorption capacities for 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D). The results showed that these pollutants were better adsorbed on the activated carbon obtained with KOH, which has a microporosity and a specific surface area greater than that obtained with K 2 CO 3 [206]. In the same context, Laksaci et al [136] studied the influence of the combination of CO 2 with KOH on the morphological properties and the sorption capacities of adsorbents from coffee grounds for phenol and MB.…”

“…In addition, the search for inexpensive alternative resources as well as methods of preparing activated carbon has attracted the attention of scientific researchers. Several researchers are interested in converting waste from the polymer and textile industries into activated carbon as a favorable approach [176,206,[217][218][219]225]. In this context, activated carbon derived from acrylic fiber waste is obtained by physical activation in the presence of air via controlled heat treatment and used as an adsorbent for the removal of MB from aqueous media [176].…”