ABSTRACT
Organic substance (O.S) in industrial phosphoric acid (IPA) solution is often tacked placed creates a major problem for IPA quality. This study was performed to assess the efficiency of Iron Intercalated Bentonite Nanoparticles (IIBN) coupled with the ultrasonic irradiation named sono-adsorption process for treating IPA 54% P2O5 contained O.S. XRD, SEM and BET were performed for the characterization of as-prepared adsorbent. Several conditions such as adsorbent dosage, molar ratio (OH/Fe) and time were investigated in retention experiments at acidic pH and T° of 40 ± 1 °C. The sono-assisted retention parameters were optimized by using NEMROOD software. The interaction impact of study condition on the final retention capability of the organism has been revealed by ANOVA software. Accordingly, the organic substance removal can be retained more than 83% by a sonication time of 0.5 h, absorbent dosage of 1.2 g/L and a molar ratio (OH/Fe) of 1.37. The absorbability of O.S was also evaluated by using the three parameters retention isotherms and kinetic analysis.
ABSTRACT
The current problem of excess impurities in industrial phosphoric acid (IPA) 54 % P2O5 makes phosphates industries look toward low-cost but efficient adsorbents. In the present study, iron-oxide-modified bentonite (Fe-PILB) was prepared and investigated as a possible adsorbent for the removal of organic matter (OM) like humic acid (HA), chromium (Cr(III)), and zinc (Zn(II)) from IPA aqueous solutions. These adsorbents were characterized using XRD, TEM, and BET. The adsorption of impurities is well described by the pseudo-second-order model. The results indicate that Fe-PILB has a good ability to resist co-existing anions and the low-pH condition of IPA and owns a relatively high-removal capacity of 80.42 and 25 % for OM, Cr(III), and Zn(II). The mechanism of adsorption may be described by the ligand and ion exchange that happened on the active sites. The selected order of adsorption OM > Cr(3+) > Zn(2+) showed the importance of the competitive phenomenon onto bentonite materials' pore adsorption. For the adsorption of OM at the low pH of IPA, H-bond complexation was the dominant mechanism. From the adsorption of heavy metals and OM complex compounds contained in IPA 54 % on Fe-PILB, the bridging of humic acid between bentonite and heavy metals (Zn(II) or Cr(III)) is proposed as the dominant adsorption mechanism (bentonite-HA-Me). Overall, the results obtained in this study indicate Fe-pillared bentonite possesses a potential for the practical application of impurity (OM, Zn(II), and Cr(III)) removal from IPA aqueous solutions.