Targeting of cationic organic pesticide residues using polymer inclusion membranes containing anacardic acid from cashew nut shell liquid as a green carrier

Many emerging organic pollutants exist as cationic residues at environmentally relevant pH. This indicates a need to develop economically viable and robust methods to remove such residues from environmental waters. In this paper, we report using polymer inclusion membranes (PIMs) containing anacardic acid (AA), sourced from cashew nut shells, as an acidic carrier for the extraction and transport of 4-amino-2-chloropyridine (ACP), paraquat and diquat as representative target solutes of organic pesticide residues in aqueous solutions. Amounts of cellulose triacetate (CTA) as polymer, 2-nitrophenyl octyl ether (NPOE) as plasticiser, AA as carrier, and 1dodecanol as modifier were used to prepare membranes. An optimal composition of 30 wt% CTA, 40 wt% NPOE, 10 wt% AA and 20 wt% dodecanol produced an initial flux of 364 (+/- 16) x 10-8 mol m- 2 s- 1 for transport of ACP. The extraction performance of AA was comparable to bis-(2-ethylhexyl) phosphoric acid, a widely used acidic carrier, in PIMs of similar composition. PIMs utilizing AA were also successfully applied to a sample of environmental water for the competitive recovery of ACP, paraquat and diquat, each at 500 mu g/L. Using chemicals from plants as active reagents was shown to be an effective strategy to enhance the green chemistry credentials associated with methods for water remediation.