New biosorbents based on the seeds, leaves and husks powder of Moringa oleifera for the effective removal of various toxic pollutants

ABSTRACT

A new hydrogel beads-sponge structure (these new beads combine the properties of the beads with the sponge character) with a super rate of swelling hydrogel in water and wastewater and a large porosity was created during this research. New biosorbents were obtained by modification of three parts of Moringa oleifera (seeds, leaves and husks). Prepared adsorbent beads were characterised by some analytical methods, viz. FT-IR, SEM and SEM-EDX. The effects of operational parameters, such as pH, dose of sorbents, temperature, and others were investigated and compared with those of initial powder. EDX results of M. oleifera (MO) and M. oleifera-gelatin (MO-GEL) had the highest percentage of amino groups. The FT-IR spectra showed the existence of – NH, – OH, – COOH functional groups in the biomass and the modified beads. The maximal adsorption potential was observed at the range of pH value of (5–6) for all pollutants tested and the pH_pzc showed the charge carried by MO and MO-GEL in different pH conditions.

Conclusively, the objective of this study was the valorisation of the powder in the form of beads to facilitate its use in sorption processes, and without disturbing or diminishing efficiency. This study showed that the sorbents based on Moringa oleifera in their bead forms were good alternative adsorbent that could be used for recovery of dyes (the sorption capacity reaches up to 175.28 mg CV g⁻¹ (≈44%) and 493.76 mg BG g⁻¹ (≈65.8%) for MOS-GEL beads and reaches up to 475.27 mg CV g⁻¹ (≈63%) and 575.82 mg BG g⁻¹ (≈83%) for MOL-GEL) and heavy metal from water (47.08 mg Pb g⁻¹ ($\approx$57% for MOS-GEL), 25.99 mg Pb g⁻¹ ($\approx$38.41% for MOL-GEL) and 32.25 mg Pb g⁻¹ ($\approx$24,6% for MOH-GEL)).

KEYWORDS:

• Moringa oleifera
• biosorption
• toxic metal
• dyes
• wastewater
• MO-GEL

Acknowledgments

This paper is a personal work with the objective of designing some super biosorbents that are able to remove some of toxic pollutants that are used in the treatment of industrial solutions.

This project is part of the use of new biosorbents in the treatment of pollutants and the encouragement and valorization of master’s students in the research field. The majority of experiments were performed by the two master’s students of origin of ‘Mali’ and ‘Zimbabwe’, named, respectively, ‘Adama Traore’ and ‘Coffee Calvin Tinashe’ and this plant is of Mali origin. I am also thankful to Prof. Mu. Naushad, King Saud University for his valuable corrections to improve this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.