Study on an effective industrial waste-based adsorbent for the adsorptive removal of phosphorus from wastewater: equilibrium and kinetics studies

Abstract

In this work, an effective adsorbent for removing phosphate from aqueous solution was developed from modifying industrial waste--lithium silica fume (LSF). The characterization of LSF before and after modification was investigated using an N2 adsorption-desorption technique (Brunauer-Emmett-Teller, BET), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Studies were conducted to investigate the effect of adsorbent dose, initial solution pH, contact time, phosphate concentration, and temperature on phosphate removal using this novel adsorbent. The specific surface area for modified LSF (LLSF) is 24.4024 m(2)/g, improved 69.8% compared with unmodified LSF. XRD result suggests that the lanthanum phosphate complex was formed on the surface of LLSF. The maximum phosphate adsorption capacity was 24.096 mg P/g for LLSF, and phosphate removal was favored in the pH range of 3-8. The kinetic data fitted pseudo-second-order kinetic equation, intra-particle diffusion was not the only rate controlling step. The adsorption isotherm results illustrated that the Langmuir model provided the best fit for the equilibrium data. The change in free energy (△G(0)), enthalpy (△H(0)) and entropy (△S(0)) revealed that the adsorption of phosphate on LLSF was spontaneous and endothermic. It was concluded that by modifying with lanthanum, LSF can be turned to be a highly efficient adsorbent in phosphate removal.

Phosphate Adsorption by Montmorillonites Modified with Lanthanum/Iron and a Laboratory Test using Water from the Jacarepaguá Lagoon (RJ, Brazil)

“…The mixture was magnetically stirred for 24 h at room temperature (298 K). 28,36 Thereafter, the material was filtered, washed with deionized water, and dried at 378 K. Before and after the process of modification, the granulometry was adjusted with a 100 mesh sieve (internal aperture equal to 0.149 mm).…”

“…The kinetic models of pseudo-first order and pseudosecond order are usually well-suited for describing the kinetic parameters of adsorption processes that occur at the interface of the solid adsorbent and solution. 36,39 In addition, the intraparticle diffusion model can also describe the adsorption processes. 39,40 The kinetic models of pseudo-first order, pseudo-second order, and intra-particle diffusion in their linear forms were evaluated according to equations 1, 2, and 3, respectively: [41][42][43][44] (1)…”

“…The experimental data were tested and compared with two isotherm models, Langmuir and Freundlich. 36,39 The linearized Langmuir isotherm model is described by the following equation: (6) where Q max is the maximum adsorption capacity (mg g -1 ), and K L is the Langmuir equilibrium constant (L mg -1 ).…”

Facile synthesis of novel 3D flower-like magnetic La@Fe/C composites from ilmenite for efficient phosphate removal from aqueous solution

“…Phosphate solution was prepared by dissolving analytical grade anhydrous potassium dihydrogen phosphate (KH 2 PO 4 ) in distilled water. The phosphate adsorption experiments were carried out in sealed conical asks with 50 mL of 10 mg L À1 P. The effect of lanthanum impregnation ratio, adsorbent dosage (1-8 g L À1 ), pH (3)(4)(5)(6)(7)(8)(9)(10)(11) and contact time (0-180 min) was studied. Aer the adsorption process, the suspension was ltered through a 0.45 mm membrane, and the remaining phosphate concentration was determined according to the molybdenum blue spectrophotometric method (UV/Vis spectrophotometer at l max ¼ 700 nm).…”

“…5 In particular, lanthanum (La) has attracted special attention, since it is highly active in binding phosphate and forming environmentally friendly lanthanumphosphate complex, which is highly insoluble (pK ¼ 26.16). 4,6 Therefore, lanthanum has oen been preferred as a loading agent to enhance the removal of phosphate from aqueous solutions. Various La loaded porous adsorbent such as Laloaded mesoporous silica, 7 La-loaded activated ber 8 and Laloaded zeolite 9 have been proven to be favorable for improving phosphate uptake capacity.…”