Fluoride contamination in and around selected geothermal sites in Odisha, Eastern India: assessment of ionic relations, fluoride exposure and remediation

Maitra, Arpita; Keesari, Tirumalesh; Roy, Annadasankar; Gupta, Saibal

doi:10.1007/s11356-020-10948-0

Cited by 17 publications

(1 citation statement)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Removal of

F^{-}

remains a challenging task because of operational and maintenance cost, complex technology involved, and huge sludge generation that always demands cost‐effective geosorbent, which can also form in a fluoride‐polluted environment, acting as a natural sink. Ion exchange, membrane filtration, precipitation, coagulation, and biodegradation are the routinely adopted treatment techniques for

F^{-}

removal, which require high cost and involve complex mechanisms (Jha et al, 2013; Maitra et al, 2021; Mohapatra et al, 2009; Roy & Dass, 2013).…”

Section: Introductionmentioning

confidence: 99%

Fluoride retention kinetic and equilibrium studies on layered double hydroxides under ambient conditions: Implications on pond–stream–hot spring–well water remediation

Mahajan

Paikaray

2022

Water Environment Research

View full text Add to dashboard Cite

Fluoride deficiency and toxicity severely affect a large population globally. Hence, a low‐cost geosorbent is in demand to overcome fluorosis hazards where in situ retardation is prioritized over pilot‐scale waste water treatment. This study reports the fluoride removal potential of MgFe‐type layered double hydroxide (HT‐LDH) and its calcined form at 500 and 800°C for their usability for treatment of polluted streams, ponds, wells, and hot spring water. Rapid uptake with >33% removal in 24 h was found by the adsorptive method, whereas the co‐precipitation process removed >16 mg/L (>83%) in 1 h. The efficiency was further enhanced upon calcination at 500°C with >95% removal up to five times regeneration, unlike that at 800°C. It was demonstrated that multilayer sorption onto heterogeneous surface sites is majorly controlled by surface adsorptive and ion exchange mechanisms. Acidic pH, low aqueous F−, and temperature >25°C favored greater uptake, whereas competitive anions slightly enhanced its potential in the order normalNO3−>normalSO42−>normalPO43− in adsorptive removal. In the co‐precipitation process, competing anions slightly hindered F− retention, whereas high temperature and low aqueous F− led to greater F− retention. No F‐bearing solid phases were evidenced upon its retention, except lowering the HT‐LDH crystallinity and rearrangement of normalCO32− surface functional groups. The fluoride contents of natural water were lowered drastically up to 77% in 60 min upon precipitation of HT‐LDH by maintaining alkalinity and a di‐/trivalent cationic ratio of 2.0. Practitioner Points F^− uptake is rapid on heterogeneous surface sites with multilayer sorption mechanism Greater F^− removed by coprecipitation technique compared with adsorptive pathway Acidic medium and temperature >25°C favor greater F^− retention NO_3^−+PO_l4^(3−) slightly enhanced F^− uptake by adsorption but lowered in coprecipitation Formation of LDH from natural waters lowered F^− content up to <77%

show abstract

“…Removal of