Modification of Sargassum angustifolium by molybdate during a facile cultivation for high-rate phosphate removal from wastewater: structural characterization and adsorptive behavior

Abstract

In this paper, a new and facile approach for molybdate loading in the brown algae of Sargassum angustifolium is introduced. The molybdate ions were entered into the algae body during a short cultivation to produce algae–Mo as a novel adsorbent for eliminating phosphate ions from synthetic and real wastewaters. Results of the surface analysis showed that molybdate loading onto the algae was successfully performed. Herein, basic variables, such as initial solution pH, adsorbent dosage, contact time, phosphate concentration, and temperature, were investigated in detail to assess the phosphate adsorption performance of algae–Mo. The pseudo-second-order kinetic model fitted our acquired experimental kinetic data most appropriately, in comparison to the use of a pseudo-first-order model. The Langmuir model appeared to fit the adsorption data more desirably than that of Freundlich and Dubnin–Radushkevich models, with a maximum phosphate adsorption capacity of 149.25 mg/g at 25 °C. The finding of the thermodynamic study revealed that the phosphate adsorption onto algae–Mo was spontaneous, feasible, and endothermic in nature. The study on Mo2+ ions leaching strongly suggested that the risk of Mo2+ leakage during phosphate adsorption was negligible at a wide pH range of 3–9. The adsorption efficiency attained was 53.4% at the sixth cycle of reusability. Two real wastewaters with different qualities were successfully treated by the algae–Mo, suggesting that the algae–Mo could be ordered for practical wastewater treatment.

Chemically Modified CaO/Fe3O4 Nanocomposite by Sodium Dodecyl Sulfate for Cr(III) Removal from Water

“…The values of ΔS°and ΔH°can be calculated from the intercept and slope of the ln K th versus 1/T plot, expressed as [42,43]:…”

Synthesis of Fe3O4 Nanoparticles Modified by Oak Shell for Treatment of Wastewater Containing Ni(II)

“…Contact time is one of the important parameters in bio-adsorption process. 23,24 The effect of stirring time on the performance of OSMMN in adsorbing Ni (II) was investigated. The solution pH and oak shell magnetic nanoparticles dosage were fixed at their obtained optimum values.…”

“…Two important isotherm models were selected in this study, Langmuir and Freundlich isotherm models. 20,23,25 Freundlich model is an empirical model and can describe adsorption capability of adsorbents. This model is applied for non-ideal adsorption on heterogeneous surfaces.…”

“…Also, the Langmuir model describes the monolayer bio-sorption process onto the adsorbent surface with specific binding sites. The linear form of Longmuir model is written as follows: 23 (3)…”

“…The value of separation parameter indicates the shape of isotherm to be either favorable (0 < R L < 1), unfavorable (R L > 1), linear (R L = 1) or irreversible (R L = 0). 23,24 The capacities of magnetic oak shell nanoparticles to adsorb Ni (II) were examined by measuring the initial and the final concentration of Ni (II) at the pH of 4.5 and the temperature of 25 °C in a batch system. Both Langmuir and Freundlich adsorption isotherms were used to normalize the adsorption data.…”