Removal of manganese from water by modified groundwater plant sludge: Mechanism and application as filter media

Application of modified water treatment residuals in water and wastewater treatment: A review

“…Alkali modification of WTRs, on the other hand, introduces oxygen-containing functional groups, which increase the negative charge on exchange sites on the surface of alkali modified WTRs. Alkalization augments the surface area and negative charge of alkalized WTRs, resulting in the deprotonation of accessible sites and the attraction of positively charged contaminants [ 61 ].…”

“…A significant increase in pore diameter and specific surface area was observed because of the replacement of the larger cations in raw WTRs with sodium ions and collapse in pore walls after high temperature firing [ 35 ]. After alkali modification of WTRs, Jiang et al [ 61 ] reported a dense laminar structure of WTRs with looser and larger pores. The flat surface of WTRs becomes covered in small particle bumps, hence increasing their surface area [ 61 ].…”

“…After alkali modification of WTRs, Jiang et al [ 61 ] reported a dense laminar structure of WTRs with looser and larger pores. The flat surface of WTRs becomes covered in small particle bumps, hence increasing their surface area [ 61 ]. Vinitnantharat et al [ 57 ] found that acid activated WTRs have more smooth and wide pores than raw WTRs indicating leaching of cations from the adsorbent surface on acid activation.…”

“…The Na + ions exchanged the Fe 3+ , Ca 2+ and Mg 2+ ions on modified WTRs surface. This increased the modified WTRs’ aperture size by 116.43% and surface area by 67.67% compared to raw WTRs [ 61 ].…”

“…removal efficiency = 85% [ 131 ] Thermal and acid activated WTRs F Initial concentration = 10 mg/L Temperature = 25 °C 40 g/L Max. removal efficiency = 98.90% [ 57 ] Calcium alginated WTRs F Temperature = 30 °C Time = 12 h pH = 6 10 g/L 39.59 mg/g [ 16 ] WTRs-geopolymer F Concentration = 100 mg/L, Time = 24 h pH = 8.3 10 g/L Removal efficiency = 100% [ 132 ] Fe WTR composite F pH = 6.5, Time = 1.5 h Initial concentration = 50 mg/L 10 g/L 16.09 mg/g [ 3 ] Alkali modified WTR Mn Time = 12 h 100 g/L 26.39 mg/g [ 61 ] …”