Evaluation of La-Doped Mesoporous Bioactive Glass as Adsorbent and Photocatalyst for Removal of Methylene Blue from Aqueous Solution

Abstract

A series of La-doped mesoporous bioactive glass (BG-La) materials with excellent biosafety and hypotoxicity have been prepared and tested as adsorbent. The study was aimed to evaluate the possibility of utilizing BG-La for the adsorptive removal of methylene blue (MB) from aqueous solution and test the adsorption and desorption behavior of this new material. The process parameters affecting adsorption behaviors such as pH, contact time, and initial concentration and the photocatalytic degradation of MB were systematically investigated. The result showed that BG-La had excellent removal rate (R) of MB, and BG-La showed better photocatalytic effect than undoped mesoporous bioactive glass (BG). Furthermore, the MB loaded BG-La was easily desorbed with acid solution due to its electronegativity and mesoporous structure. The result indicated that these materials can be employed as candidates for removal of dye pollutant owing to their high removal rate, excellent photocatalytic effect, desorption performance, and their reusability.

Novel Inorganic Membranes Based on Magnetite-Containing Silica Porous Glasses for Ultrafiltration: Structure and Sorption Properties

“…Studying adsorption kinetics can provide information on the adsorption mechanism [ 76 ]. The kinetic mechanism of the adsorption process consists of three consecutive steps of mass transport.…”

“…The adsorption isotherm is important in understanding the interactions between solutes and adsorbents, as it indicates how adsorbed molecules distribute themselves between the liquid and solid phases until the adsorption process reaches an equilibrium state [ 76 ]. Different isotherm models are used to analyze the adsorption equilibrium data.…”

“…Different isotherm models are used to analyze the adsorption equilibrium data. They are a valuable tool for reliable prediction of the adsorption process and quantitative comparison of adsorption behaviors [ 69 , 76 ]. The models used to analyze the data in this work differ from each other in how the heat of adsorption varies with surface coverage: the Langmuir isotherm does not assume that the heat of adsorption decreases as surface coverage increases; the Freundlich suggests a logarithmic decrease, while Temkin suggests a linear decrease.…”

“…The monolayer adsorption process means that no further adsorption occurs once adsorption takes place at specific sites on the adsorbent. Therefore, the adsorption is closely related to the surface area of the adsorbent and the driving force, such as the London-van der Waals force [ 76 ]. The maximum sorption capacity was demonstrated by the glass sample 6/65-8 (10.5 mg/g).…”