Iron oxide magnetically assisted removal of di-carboxylic acids from water samples

It has been proposed a magnetically assisted removal method called magnetic solid phase extraction (MSPE) for removing di-carboxylic acids (DCAs) as organic contaminations from water sources as a treatment procedure(1). Different parameters effects MSPE of DCAs were investigated and optimum condition for pH, contact time, amount of absorbent and concentration of adsorbate was obtained as the following: 5.5, 120min, 50mg and 150ppm, respectively using HPLC. Longmire isotherm was used for investigating the adsorption process and calculating the Longmire equation and having parameters such as b, qm and -∆G of 4.21, 120 and 4.56 for oxalic acid, 1.81, 109 and 1.64 for fumaric acid 192, 106 and 1.07 for malonic acid and 1.92, 108 and 1.30 for glutaric acid, respectively. So, according to the amount of r and ∆G there was favorably and spontaneously adsorption process for DCAs. The adsorption was done in the approximately 120 min that shows a fast and easy adsorption of DCAs on the MNPs surface. For confirmation of DCAs adsorption on MNPs FT-IR and TGA techniques were done. Adsorption capacity of oxalic acid, malonic acid (MA), glutaric acid (GA) and fumaric acid (FA) from water sources are 7.5-8.2% similar to the proposed method. Adsorption and desorption process was investigated continuously for five times for reusability of MNPs. Analytical parameters for evaluating the methods such as the linear range, r2 and LOD are respectively 0.001ng/ml-200mg/L and 0.99. On the other hand, the amount of LOD and RSD of the proposed method were obtained 0.086, 0.0063, 0.0345 and 0.088 and of 4.43, 2.9, 1.68 the real samples of Utah lake and tape water of Utah were investigated(2,3).