Evaluation of almond shells magnetized by iron nano-particles for nitrate removal from Aqueous Solution: study of adsorption isotherm

One of the most common environmental pollutants to groundwater and surface water are nitrates. High nitrate levels in drinking water causes diseases such as methemoglobinemia in children, gastric cancer and abortions. This study aimed to investigate the absorption isotherm of almond shell carbon activated with the magnetic nanoparticles to reduce nitrate in aqueous environments. In This experimental study morphology of synthesized adsorbent was analyzed using FESEM and BET techniques. The effective parameters on nitrate ion absorption process such as pH (4-8), the amount of absorbent (0.25-1 g/L), the initial concentration of nitrate ions (25-400 mg/L) and contact time (20-100 min) were investigated. In this research, Taguchi method was applied for determining the sample size and statistical analysis. Findings of FESEM and BET techniques confirmed that magnetic nanoparticles size and specific surface area in the synthesized absorbent were 23-27 nm and 105.480 m2/g, respectively. At optimal pH 4 and equilibrium time of 20 min, absorption efficiency increased with absorbent increase by 1 g/L and reduction in the initial concentration of nitrate ions (85.86±4.6). The results of adsorption equilibrium isotherms showed that nitrate absorption process follows the Langmuir isotherm (R2=0.924). The almond shell activated with iron nanoparticles has a good ability to remove nitrate ions from aqueous solutions. So, use of this relatively easy and simple technology is an effective step in removing nitrate from water.