Oxidised carbon nanoplatelets for remediation of inorganic pollutants from a natural industrial effluent

Industrial effluents are a major environmental contaminant; therefore, strategies are needed to manage and reduce potential hazards. This study evaluated the removal of inorganic pollutants from industrial effluent collected from a manufacturing company in Harare using oxidized carbon nanoplatelets (OCNPs) through an adsorption process. The removal was spontaneous ( $$\varDelta {\text{G}}_{\text{a}\text{d}\text{s}}^{^\circ}$$ < 0) and followed a pseudo-second-order kinetic model. The maximum equilibrium adsorption amounts recorded for Al, Fe, Ca, and Pb were approximately 9522, 456, 106, and 0.89 mg g−1, respectively. The optimal pH, adsorbent dose, temperature (considering Gibbs free energy), and contact time for treating the industrial effluent were 6, 20 g L−1 of industrial effluent, 40 °C, and 1.5 h, respectively. The removal of Al, Fe, Pb, and Ca contaminants from pristine industrial effluent by OCNPs was best described by a spontaneous monolayer adsorption model. The oxygen-containing moieties, especially the OHˉ groups on the OCNPs, enhanced remediation by attracting and chemically binding inorganic pollutants to the surfaces of the OCNPs. Thus, the study demonstrated that OCNPs are effective adsorbents for managing industrial effluent contaminated with inorganic pollutants. This offers a sustainable, cost-effective, and versatile solution that can significantly protect the environment.