Facile and cost-effective fabrication of activated charcoal-carboxymethyl cellulose composite fiber for high-rate water-softening application

Fabrication of a simple carboxymethyl cellulose (CMC)-anchored activated charcoal (AC)-based low-cost composite fiber for water-softening in a membrane system. [Display omitted] •Facile fabrication of activated charcoal-carboxymethyl cellulose (AC-CMC) fiber.•Sorption kinetics of the fiber was 15.5 times faster than that of commercial beads.•The fiber exhibited proficient reusability performance.•The fiber was successfully applied in membrane system.•The fiber showed high breakthrough bed volume within a short residence time. Sustainable cost-effective activated charcoal-carboxymethyl cellulose (AC-CMC) fiber was developed through a benign method for high-rate water-softening applications. The as-developed fiber was characterized using FTIR, BET, stereomicroscope, XRD, and FESEM. The fiber was not only used for the removal of hardness (adsorptions of Ca(II) and Mg(II)) from different aqueous media but also successfully applied in a membrane system. The effect of pH, contact time, isotherm, and kinetic experiments were conducted to examine the sorption efficiency of the fiber. The fiber showed an adsorption efficacy of 46.1 mg/g and fast rate kinetics of 0.1521 L/min for Ca(II). The results were compared to that of the commercial ion-exchange fibers and beads namely Fiban K-1 and 001X8 NA, respectively. The experimental results fitted the best with the Langmuir isotherm and pseudo-first-order kinetic models. It can be assumed that the electrostatic and dipole-ion interactions between the fibers and Ca(II)/Mg(II) played a vital role during the sorption process. The fiber also showed proficient reusability performance. The developed fiber was applied in the membrane system and it showed high breakthrough bed volume within a short residence time of 25.7 seconds. So, this work demonstrates the significant potential of the AC-CMC fiber for high-rate water-softening application in the membrane system.