Abstract
The present study aims to examine the efficiency of laterite grains (LG) and acid activated laterite grains (AALG) as an adsorbent for removal hexavalent chromium and ferric ion from synthetic wastewater, under laboratory conditions. Adsorption of hexavalent chromium and ferric ion from synthetic wastewater is examined by batch and column studies wherein it is found to be dependent on pH, Contact time, adsorbent dosage and initial adsorbate concentration. Percentage removal enhances with the increase in adsorbent dosage and with low pH, the optimal removal is achieved at pH=2. AALG is found to investigate possibility of improvement in removal efficiency of hexavalent chromium. The removal efficiency of AALG is found to be significantly higher than the efficiency obtained from LG, at pH=7. An adsorbent dosage 2g of LG is found to be optimum for removal of ferric ion with low initial concentration of 2.5 mg/L. The equilibrium adsorption data obtained from batch studies were fitted with Langmuir and freundlich isotherm for both hexavalent chromium and ferric ions. The percentage removal obtained from batch adsorption studies were found to be higher than that obtained by column studies for both the adsorbates.
Highlights
Since last 5 decades, environmental pollution due to rapid industrialization has created more modern problems
The present study aims to examine the adsorption characteristics of laterite grains (LG) intended to be used as an adsorbent for removal chromium size ranging from 0.6 mm to 1.18 mm in synthetic wastewater treatment
In order to study the effect of initial adsorbate concentration upon adsorption, column study was conducted for two different initial metal ion concentrations
Summary
Since last 5 decades, environmental pollution due to rapid industrialization has created more modern problems. Industries have a large prospective to cause streams, river, lake and sea pollution, thereby causing increased addition of heavy metals into the environment (Sahu et al 2009). Environment pollution by toxic heavy metals occurs through industrial, military and agricultural processes (Ajmal, Ali Khan Rao, and Siddiqui 1996).A serious threat that posed to the environment due to the discharge of heavy metals into the streams there by causing accumulation leading to adulteration of food chain. Toxicity is caused due to the presence of heavy metals like Ni, Zn, Cu, Cd, Cr, and Hg are toxic even in trace amounts. Metal species produced due to the various activities, when released into the environment they increase persistently (Chand, Agarwal, and Kumar 1994). It is a mandate to monitor their levels within permissible limits as recommended by the World Health Organization (WHO) in drinking water, wastewater and water used for farming and recreational uses
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