Optimum Operating Conditions for the Removal of Phosphate from Water Using of Wood-Branch Nanoparticles from Eucalyptus camaldulensis

A batch bio-sorption experiment was conducted on Eucalyptus camaldulensis Dehnh. wood-branch in the form of woody sawdust nanoparticles (nSD-KF) to evaluate their potential efficiency as phosphate bio-sorption capacity. The operating parameters of phosphate bio-sorption including contact time, initial concentration, pH, temperature, dosage, size, competing ion, and the possible mechanisms responsible for phosphate removal from water were investigated. The nSD-KF were green-synthesized by ball mill grinder and phosphate solutions with various concentrations were performed. The results revealed that the maximum adsorption capacity (qmax) value of nSD-KF was 50,000 µg/g. In addition, the removal efficiency of nSD-KF significantly increased with the increase of initial phosphate concentration, contact time, temperature, and dosage. However, it decreased with the increase of pH and in double-system solution with the presence of ammonium ions. At the application study, the nSD-KF successfully removed 87.82% and 92.09% of phosphate from real agricultural wastewater in a batch experiment and in a column experiment, respectively. Adsorption efficiency of nSD-KF for phosphate increased after the first and second regeneration cycles, but it decreased after the third and fourth cycles. The poor to moderate phosphate desorption from nSD-KF sorbent indicates the stability of phosphate bound to nSD-KF materials. Regardless, biodegradability of nSD-KF-loaded phosphate is possible, and it will be a good source of phosphate to a plant when added to the agricultural soil as a supplemental application of fertilizer. In conclusion, nSD-KF could be considered as a promising lignocellulosic biomaterial used for the removal of phosphate from waters as bio-sorption process.