Potential of natural ferruginous manganese (NFM) ore as a natural adsorbent for As(III) removal at low concentration

ABSTRACT

The findings of the current work pertain to the assessment of potential of natural ferruginous manganese (NFM) as a green, effective and economic adsorbent for decontamination of As(III) from aqueous media. Several techniques such as SEM coupled with EDX, BET, FTIR and XRD were used to characterise the NFM adsorbent. The adsorption parameters such as pH, contact time, temperature and NFM dose were considered and investigated in detail for the As(III) removal. The adsorption of As(III) was observed to increase with increasing temperature, concentration, adsorbent dosage and contact time of the system. The maximum As(III) adsorption of 1.9 mg g⁻¹ over NFM revealed it to be an effective adsorbent for removing As(III) in the range of 0.45–2.5 mg/L. Langmuir, Freundlich and Dubinin Radushkevich (D-R) adsorption models were used to analyse the adsorption data and the Langmuir model provided the best fit with high regression coefficient (R²). The time profile studies demonstrated that As(III) uptake followed a pseudo-second-order kinetics while the maximum As(III) removal of 96% was obtained within the first 50 min of contact time within a pH range of 4–6. Thermodynamics results showed that As(III) adsorption by NFM was spontaneous and endothermic in nature. Based on the results, it is claimed that natural NFM can effectively serve as green, economic and potential natural adsorbent for As(III) removal and likewise from the aqueous solutions.

KEYWORDS:

• As(III)
• ferruginous manganese ore
• adsorption
• isotherms
• kinetics

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research work was supported by National Research Program for Universities (NRPU) Project No. 8817 by the Higher Education Commission of Pakistan.