Indigenous hematite iron ore was chemically activated as a function of various hydrogen peroxide concentrations (0.5, 1, 1.5, and 2.0 M), activation time, and iron ore size. Adsorption potential was evaluated at various initial arsenic concentrations, contact time, adsorbent dose, and particle size. Maximum 95% removal efficiency was achieved at 600-μm size of iron ore, activated with 0.5 M concentration of hydrogen peroxide at 24 h of activation time. The experimental data were further evaluated through Langmuir and Freundlich isotherms. The maximum 14.46 mg/g of adsorption capacity was observed through Langmuir isotherm. Moreover, adsorption kinetics was evaluated using pseudo-first-order and pseudo-second-order kinetics, and the intra-particle diffusion model. The kinetics of arsenic adsorption was best described by using the pseudo-first-order kinetics with a kinetic rate of 0.621 min−1. The hematite iron ore before and after arsenic adsorption was characterized by XRD, SEM, and EDX.

Experimental investigations of arsenic adsorption from contaminated water using chemically activated hematite (Fe2O3) iron ore

Fluoride Toxicity in Rajasthan, India: Human Health Risk Assessment, Low-Cost Water Filter Preparation, and Contaminant Remediation

The fluoride content in drinking water is an existing concern for public health engineers and water scientists. An optimum concentration of fluoride in drinking water has beneficial effect including the prevention of dental caries and calcification of dental enamel for the children. However, on the contrary, excess fluoride content over permissible concentration galvanizes the risk of dental fluorosis, skeletal fluorosis, and crippling skeletal fluorosis. In this study, an effort has been made to have an insight into the fluorosis affected states of India and to recommend some cost-effective and efficient technology to eradicate fluorosis from India. The column study has been adopted for activated alumina, bone charcoal, and a batch study for cement granule. The present study has revealed the fluoride uptake capacity of 97.9% in the case of bone charcoal and 85.3% in the case of activated alumina which is more promising and efficient as compared to cement granules. But the manufacturing process of bone charcoal has certain environmental constraints and the cost is also much higher for the same. The maximum removal capacity has been obtained as 3.44 mg/g of activated alumina at a flow rate of about 5 l/h. The test results found for activated alumina have best fitted to the Langmuir adsorption isotherm model. Therefore, considering the economic constraints of the rural population and the ease of operation, the adsorption filter using activated alumina as the media might be recommended to remove fluoride from drinking water at the domestic level.

Performance Analysis of Some Low-Cost and Locally Available Adsorbents that Remove Excess Fluoride Ion from Raw Water to Develop a Filter for the Rural Population

Chaiti Ray

Papers

Performance Analysis of Some Low-Cost and Locally Available Adsorbents that Remove Excess Fluoride Ion from Raw Water to Develop a Filter for the Rural Population