Magnetically engineered sulfurized peat-based activated carbon for remediation of emerging pharmaceutical contaminants.

Activated carbon derived from peat-based biomass was sulfurized and magnetized forming magnetically-engineered sulfurized peat-based activated carbon (MEPBAC) and used for adsorption of caffeine (CFN) and sulfamethoxazole (SMX) from aqueous media. Modification increased the surface area (724 m2/g) and introduced sulphur-groups and Fe-based nano-structures in MEPBAC. Sulphur-groups enhanced adsorption efficiency, whereas Fe-based nano-structures facilitated easy magnetic separation of MEPBAC after intended use leading to high reusability with consistent removal efficiency (∼95 %). Response surface methodology was employed for design of experiments and process optimization. The results revealed that the maximum removal (SMX 94 %; CFN 97 %) could be achieved at an adsorbent dose of 1.4 and 1.6 g/L, respectively (pH 11, 311 K). Adsorption kinetics was best explained by a pseudo-second-order kinetic model. Adsorption data of SMX was fitted better to Langmuir (linear) and Freundlich (non-linear) isotherms, whereas that of CFN was fitted well with Freundlich (linear) and Langmuir (non-linear) isotherms (R2 ≥ 0.99).

Profiling of emerging contaminants and antibiotic resistance in sewage treatment plants: An Indian perspective.

In India, sewage (partially-treated/ untreated) is randomly used for irrigation because of easy availability and presence of residual organics and nutrients. However, data on the occurrence of contaminants of emerging concerns (CECs) such as pharmaceuticals and personal care products (PPCPs) and antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in sewage is scarce in Indian perspective. Herein, for the first time, we present a quantitative contamination profiling of selected PPCPs and antibiotic resistance in untreated and biologically-treated sewage from three different sewage treatment plants, located in northern and central part of India. Profiling of PPCPs were done using LC-ESI-MS/MS whereas antibiotic resistance was analyzed using gradient PCR and qPCR techniques. PPCPs were detected both in untreated and treated samples (0.4 - 1340 µg/L). A reduction in ARB and ARG load (2-3 log) and an increase in ARG copy number with respect to beta lactams and tetracycline were observed in treated sewage. Triclosan, estrone and 17α-ethynylestradiol, ubiquitous in all samples, could be used as markers for performance monitoring of sewage treatment facilities. The results obtained in this study help evaluate health and ecological risks associated with the presence of CECs in treated sewage used for irrigation and frame future policies.