An investigation on the efficiency of low-cost adsorbents in removing uranium from water samples

Sandeep Police,Sukanta Maity,A Vinod Kumar,Sanjay Kumar Sahu,Dilip Kumar Chaudhary

doi:10.1007/s13201-020-01299-9

Sandeep Police, Sukanta Maity + Show 3 more

Open Access

https://doi.org/10.1007/s13201-020-01299-9

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Abstract

The groundwater samples were found to be contaminated with high concentrations of uranium (U) in Punjab state as well as in few other locations of India. U being chemically toxic can deteriorate health when ingested. Hence, there is a need to remove U from contaminated water using an efficient, cheap and user friendly method. A study was initiated to investigate the efficiency of low-cost adsorbents in removing U from water. Seven adsorbents were screened for U removal efficiency, among which fly ash (FA) and tea waste (TW) were found to have better removal efficiency. Solid–liquid contact time and solution pH were optimized to establish conditions for better U removal efficiency. The U adsorption on FA and TW followed pseudo-second-order kinetics with rate constant values 4.63 g/mg/min and 15.63 g/mg/min, respectively. FA and TW had the highest U removal capability at pH 6 and pH 4, respectively. The U sorption data were fitted with Freundlich and Dubinin–Radushkevich isotherm models. The U adsorption on FA and TW is found to be a physical process with mean free energy (E) values less than 8 kJ/mol. Theoretically calculated maximum adsorption capacity values indicate that FA is a better adsorbent as compared to TW, which has been further confirmed experimentally. The U adsorption on both the adsorbents has interference from Ca2+ and no interference from Fe3+ at tested U concentrations. It is also found that FA and TW are effective in decontaminating U from spiked real groundwater samples to below the WHO (Guidelines for drinking water quality, 4th ed, vol 1, World Health Organization, Geneva, 2011) limit.

Highlights

Aquatic environmental contamination is currently one of the most important issues faced globally (Idrees et al 2018; He et al 2018; Dıaz-Cruz and Barceló 2008)
The most important conclusion from the study is that the fly ash (FA) can be used to reduce the U initial concentration to less than the WHO and AERB prescribed limits with 99% adsorption
The application of intra-particle diffusion model on adsorption data indicates that both the boundary layer diffusion as well as the intra-particle diffusion is responsible for U adsorption on FA and Tea waste (TW)

Summary

Introduction

Aquatic environmental contamination is currently one of the most important issues faced globally (Idrees et al 2018; He et al 2018; Dıaz-Cruz and Barceló 2008). Among various contaminants of serious concern, heavy metals such as As, Se, Pb, Cr, Hg, Cd, U are important since they are nonbiodegradable and toxic (Pietrelli et al 2019; Gupta et al 2001; El-Bayaa et al 2009). They can accumulate in living organisms through the ingestion causing various disorders in human and can have negative impacts on agriculture and aquatic species

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Conclusion