Multivariate analysis of pharmaceutical pollutants adsorption in aqueous media with tailored waste-based carbonaceous adsorbent materials and commercial activated carbons

Abstract

The purpose of this research is to determine the effectiveness of various biocollagenic waste-based activated carbons (BWAC) and a sludge biochar (SBC) in removing emerging pharmaceutical pollutants (phenol, salicylic acid, paracetamol, diclofenac and iodixanol) present in aqueous media and its comparison with commercial and manufactured adsorbent from different origins. In addition, principal component analysis is applied to elaborate multiple linear regression models to predict maximum adsorption capacities for future new waste based-activated carbons. The BWACs were obtained by alkaline chemical activation (KOH or K2CO3), and the SBC by physical activation. Elemental and textural analysis were conducted on all adsorbents to determine their physico-chemical properties. In addition, adsorption tests of five pharmaceuticals were performed with the adsorbents. Finally, multivariate analysis (principal component analysis) was applied with the physico-chemical and adsorptive properties of the adsorbents, in order to elaborate multiple linear regression models to predict maximum adsorption capacities for future new waste based-activated carbons. The results showed high adsorption capacities of phenol and paracetamol for BWAC (up to 2.78 and 2.2 mmol g−1, respectively) influenced by chemical groups. While maximum adsorption capacity of diclofenac and iodixanol were obtained in adsorbents with higher textural development. The results of the multivariate analysis concluded that BWAC clustered in most of the adsorbents respect textural properties and differ on their chemical properties (presence of nitrogen groups). Proposed multiple linear regression models gave superior fits of r2 = 0.7512 up to r2 = 0.9830. BWACs could potentially be used as alternative sources for pharmaceutical adsorption in aqueous environment.