Enhanced adsorption of phosphate by flower-like mesoporous silica spheres loaded with lanthanum

Abstract

Monodispersed flower-like mesoporous silica spheres doped with lanthanum were synthesized via a facile method and explored as novel adsorbents for efficient phosphate adsorption for the first time. The synthesized adsorbents possessed a flower-like structure, especially with unique mesoporous channels featuring with small inner pores and wide outer pores. By raising lanthanum loading, the surface areas and pore volumes of resulting adsorbents were observed to continuously decrease, accompanied with gradually increasing pore sizes; that led to a dramatic improvement in phosphate adsorption from water. By taking cost effectiveness for practical application into consideration, the adsorbent with a theoretical La/Si molar ratio of 0.1 possessed a promising performance as compared to the literature ever reported, thanks to the large outer mesopores likely minimizing the diffusion problem caused M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT2 by the pore blocking when LaPO 4 nanorods formed during adsorption. In the kinetic study, its phosphate adsorption followed the pseudo-second-order equation better, suggesting chemisorption. Meanwhile, superior phosphate adsorption capacities were achieved within the pH range of 3.0 and 6.0; and almost unaffected by the presence of F − , Cl − , NO 3− , and SO 4 2-.

Enhancement of Kaolin Adsorption Affinity Toward Phosphate by Sequestrating Naturally Abundant Ca/Mg From Seawater

“…After introducing SO 4 2− or CO 3 2− with the same molar concentration, the phosphate removal efficiency was reduced by 8.6% and 17.6%, respectively. Similar findings have also been reported in other studies . The degree of the effects of various anions on phosphate adsorption was correlated with the affinity of adsorbents toward anions.…”

“…Similar findings have also been reported in other studies. [20,22,25] The degree of the effects of various anions on phosphate adsorption was correlated with the affinity of adsorbents toward anions. This could be explained by the K sp of CaCO 3 (3.36 Â 10 À9 ) and CaSO 4 (9.1 Â 10 À6 ), as compared with that of CaHPO 4 (1.0 Â 10 À7 ), which favored the displacement of adsorbed phosphate on KS600, especially by CO 3 2À , thus deteriorating the adsorption capacity.…”

Dendritic Fibrous Nanosilica for Catalysis, Energy Harvesting, Carbon Dioxide Mitigation, Drug Delivery, and Sensing

“…Huang et al. used lanthanum (La)‐doped DFNS for the removal of phosphorus, and the sample was prepared by the postsynthetic loading of lanthanum nitrate hexahydrate in DFNS by using the ethanol evaporation method. DFNS/La with a La/Si molar ratio of 0.1 showed the best performance, far better than the performance of similar conventional materials, which was indicative of the role of the fibrous morphology and the varied pore sizes (fiber channels) in minimizing diffusion issues and improving phosphors adsorption.…”

Synthesize of dendritic fibrous nano-silica functionalized by cysteine and its application as advanced adsorbent

“…Interestingly, Huang and coworkers, applied lanthanum (La)-doped DFNS for the adsorption of phosphorus [16]. Also, Xie et al, grafted DFNS with cyano groups and used these for the removal of some ions (Fe 3þ , Cu 2þ , and Pb 2þ ) from waste contaminated solution [17].…”