Single adsorption of diclofenac and ronidazole from aqueous solution on commercial activated carbons: effect of chemical and textural properties.

Adriana I Moral-Rodríguez,Damarys H Carrales-Alvarado,María F Alexandre-Franco,Roberto Leyva-Ramos,Carmen Fernández-González,Paola E Díaz-Flores,Esmeralda Mendoza-Mendoza

doi:10.1007/s11356-021-17466-7

Abstract

The importance of the textural and physicochemical characteristics upon the adsorption capacity of the commercial activated carbons (ACs) Coconut, Wood, Merck, Darco, and Norit towards ronidazole (RNZ) and diclofenac (DCF) from water solution was investigated thoroughly in this work. At pH = 7, Coconut AC and Wood AC presented the highest adsorption capacity towards RNZ (444mg/g) and DCF (405mg/g). The maximum mass of RNZ adsorbed onto Coconut AC was higher in this study than those outlined previously in other works. Besides, the maximum capacity of Wood AC for adsorbing DCF was comparable to those found for other ACs. The adsorption capacity of all the ACs was increased by surface area and was favored by incrementing the acidic site concentration. The π-π stacking interactions were the predominant adsorption mechanism for the RNZ and DCF adsorption on ACs, and the acidic sites favored the adsorption capacity by activating the π-π stacking. Electrostatic interactions did not influence the adsorption of RNZ on Coconut AC, but electrostatic repulsion decreased that of DCF on Wood AC. The adsorption of DCF on Wood AC was reversible but not that of RNZ on Coconut AC. Besides, the adsorption of RNZ and DCF on the Coconut and Wood ACs was endothermic in the range of 15-25°C.

Highlights

The excessive utilization of pharmaceuticals in animal and human health care has originated that considerable amounts of drugs are being discharged to the aquatic environment, sediments, soil, and food chains (Wang and Wang 2016)
The results showed that AC1 at a pH of 6.47 presented the highest adsorption capacity (61 mg/g) than the other activated carbons (ACs)
The results indicated that the textural and chemical characteristics of ACs significantly influenced the ACs adsorption capacities towards RNZ and DCF from water solutions

Summary

Introduction

The excessive utilization of pharmaceuticals in animal and human health care has originated that considerable amounts of drugs are being discharged to the aquatic environment (surface, drinking and ground waters), sediments, soil, and food chains (Wang and Wang 2016). Effluents from municipal wastewater treatment plants release pharmaceutical compounds into surface water sources since the existing biological water treatment processes do not successfully remove these compounds. Antibiotics and anti-inflammatories are some of the most commonly detected organic microcontaminants in municipal wastewater, posing a disturbing hazard since these compounds are toxic even at trace levels (Jeon and Hollender 2019). The scarce information about the toxicity of these compounds constitutes a potential hazard to human health (Halling-Sørensen et al 1998; Ternes and Hirsch 2000). Distinct antibiotics were found in the hospital residual waters, industrial and municipal wastewater and surface water. Amoxicillin (900–9940 ng/L) (Watkinson et al 2009), ampicillin (5800 ng/L) (Lin et al 2008), cephalexin (3100–64000 ng/L) (Watkinson et al 2009), ciprofloxacin (11-15000 ng/L) (Spongberg and Witter 2008; Watkinson et al 2009), sulfamethoxazole (4-9460 ng/L) (Díaz-Cruz et al 2008) and tetracycline (15000 ng/L) (Lin et al 2008) are some of the antibiotics detected in water resources

Methods

Results

Conclusion