Eutrophication caused by the excessive supply of phosphate to water bodies has been considered as one of the most important environmental problems. In this study, the powder of zirconium mesostructure (ZM), which was prepared with the template of surfactant, was immobilized in calcium alginate for practical application and the resulting material was tested to evaluate the phosphate removal efficiency. Sorption isotherms and kinetic parameters were obtained by using the entrapped ZM beads with 30 to 60% of ZM. The maximum sorption capacity increased with the higher ZM content. Q max in Langmuir isotherm was 51.74 mg/g for 60% of ZM with 7 mm of size. The smaller the particle size of the ZM beads, the faster the rate of phosphate removal, because the phosphate ions had less distance to reach the internal pores of the immobilized ZM beads. Chemical and electrochemical regeneration techniques were compared. Phosphates adsorbed on the ZM beads were effectively desorbed with NaCl, NaOH, and Na 2 SO 4 solutions. An electrochemical regeneration system consisting of an anion exchange membrane between two platinum-coated titanium electrodes was successfully used to desorb and regenerate the phosphate-saturated ZM beads. Complete regeneration was reached under optimal experimental conditions. Chemical and electrochemical regeneration proved the reusability of the bead form of the entrapped ZM, and will enhance the economical performance of the phosphate treatment process.

The use of zero-valent iron (ZVI) represents one of the latest innovative technologies for groundwater remediation. The reactivity of ZVI is enhanced when the particle size is in the nanometer range. However, nanoscale ZVI has limited field applications for in-situ groundwater remediation such as permeable reactive barriers due to its powdery form. Therefore, a method of adhering nanoparticles on a supporting material was suggested. In this paper, functionalized mesoporous silica beads were created using 3-mercaptopropyltrimethoxy silica, tetrabutyl orthosilicate, and cetyltrimethyl ammonium bromide, and their physical and chemical characteristics were measured. The highly active ZVI nanoparticles were adhered on these mesoporous silica beads. The reactivity of the resulting material was tested using nitrate solution. The reductive reaction of nitrate indicated that the degradation of nitrate appeared to be pseudofirst order with a high reaction rate constant of 0.1619 h -1 . The reaction constant decreased to 0.0122 h -1 after 3 h of experiment due to mass transfer limitation. The higher dose of the supported nanosized ZVI increased the removal rate as well as the removal efficiency of nitrate.