Hydrothermal encapsulation of lanthanum oxide derived Aegle marmelos admixed chitosan bead system for nitrate and phosphate retention

• Published in: International journal of biological macromolecules 2019-06, Vol.130, p.527-535
• Main Authors: Kumar, Ilango Aswin, Jeyaprabha, Chellappa, Meenakshi, Sankaran, Viswanathan, Natrayasamy
• Format: Article
• Language: English
• Subjects: adsorbents; adsorption; Aegle marmelos; anions; Chitosan; encapsulation; eutrophication; field experimentation; Fourier transform infrared spectroscopy; La2O3; La2O3AM@CS; lanthanum oxide; methemoglobinemia; Nitrate and phosphate adsorption; nitrates; phosphates; scanning electron microscopy; temperature; thermodynamics; X-ray diffraction
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.02.106

The potential of hydrothermal technology was utilized for the preparation of promising adsorbents in order to overcome the troubles of methemoglobinemia (blue baby syndrome) and eutrophication which is caused by excess nitrate (NO3−) and phosphate (PO43−) ions in water. Hence, in the present investigation, the chitosan (CS) encapsulated lanthanum oxide (La2O3) admixed Aegle marmelos(AM) (La2O3AM@CS) composite beads was prepared by both in situ precipitation (In situ) and hydrothermal (Hydro) methods for NO3− and PO43− adsorption. The hydro supported La2O3AM@CS composite beads hold an enhanced nitrate and phosphate sorption capacity (SC) of 27.84 and 34.91 mg/g than the other adsorbents prepared by in situ method. The characterization studies of the adsorbents such as FTIR, XRD, SEM and BET analysis were explored in detail. In batch scale, the adsorption affecting parameters such as contact time, pH, adsorbent dosage, initial adsorbate strength, competing anions and temperature was optimized. The fitted experimental data of various isotherms and thermodynamic parameters supports the feasible nature of NO3− and PO43− adsorption system. The field trial investigations and reuse of La2O3AM@CS composite beads were also executed. •Easily separable La2O3AM@CS composite beads were developed and utilized for nitrate and phosphate adsorption.•La2O3AM@CS composite beads (Hydro) possess enhanced nitrate and phosphate SC.•Nitrate and phosphate adsorption mechanism was governed by complexation, electrostatic adsorption and hydrogen bonding.•In field water, a La2O3AM@CS composite bead reduces nitrate and phosphate concentration below the tolerance limit.