Refractory pollutants like pharmaceuticals and dyes have become excessively prevalent in most Malaysian water bodies because of the growing textile and pharmaceutical industries. Hence, this work employed activated carbon prepared from freely available paper mill sewage sludge for removing chloramphenicol (CAP) and methylene blue (MB). Modest treatment of low-temperature carbonisation assisted with a short activation time of microwave radiation had been used. Analysis of variance of central composite design resulted in the optimum conditions of 440-W radiation power and 3-min activation time for optimum removal of 70% CAP and 51% MB. The surface area of the paper mill sewage sludge activated carbon (PMSSAC) improved greatly from 1.14 to 412 m2/g, with the highest adsorption capacity of 13 mg/g. The scanning electron microscope images demonstrated the efficiency of microwave radiation treatment, where more cavities and pores were observed on activated carbon for improved adsorbate penetration. The Freundlich isotherm and the pseudo-second-order model appeared to best fit the kinetic data. Furthermore, the high affinity of adsorbate towards the PMSSAC surface could be the plausible mechanism, as indicated by the high amount of adsorption within the initial stage of adsorption. Thus, it is envisaged that our PMSSAC could be effectively employed in actual wastewater systems, as evidenced by excellent CAP and MB removal. Graphical abstract: [Figure not available: see fulltext.]
