Removal of Methylene Blue from Aqueous Solution by Mixture of Reused Silica Gel Desiccant and Natural Sand or Eggshell Waste

Tatjana Juzsakova; Ali Dawood Salman; Thamer Adnan Abdullah; Rashed Taleb Rasheed; Balázs Zsirka; Rasha R Al-Shaikhly; Brindusa Sluser; Igor Cretescu

doi:10.3390/ma16041618

Removal of Methylene Blue from Aqueous Solution by Mixture of Reused Silica Gel Desiccant and Natural Sand or Eggshell Waste

Materials (Basel). 2023 Feb 15;16(4):1618. doi: 10.3390/ma16041618.

Authors

Tatjana Juzsakova¹, Ali Dawood Salman², Thamer Adnan Abdullah³, Rashed Taleb Rasheed³, Balázs Zsirka⁴, Rasha R Al-Shaikhly⁵, Brindusa Sluser⁶, Igor Cretescu⁶

Affiliations

¹ Sustainability Solutions Research Lab, Research Centre for Biochemical, Environmental and Chemical Engineering, Faculty of Engineering, University of Pannonia, P.O. Box 158, H-8201 Veszprem, Hungary.
² Department of Chemical and Petroleum Refining Engineering, College of Oil and Gas Engineering, Basra University for Oil and Gas, Basra 61004, Iraq.
³ Chemistry Branch, Applied Sciences Department, University of Technology, Baghdad 10070, Iraq.
⁴ Research Group of Analytical Chemistry/Laboratory for Surfaces and Nanostructures, Center for Natural Sciences, University of Pannonia, P.O. Box 158, H-8201 Veszprem, Hungary.
⁵ Department of Prosthetic Dental Technology, Faculty of Health and Medical Technology, Al-Farahidi University, Al-Jadiriyah Bridge, Baghdad 10070, Iraq.
⁶ Faculty of Chemical Engineering and Environmental Protection, "Gheorghe Asachi" Technical University of Iasi, 73, Blvd. D. Mangeron, 700050 Iasi, Romania.

Abstract

The purpose of this work was to develop, characterize and test new low-cost materials suitable for removing methylene blue dye from water and wastewater by adsorption. The solid materials consisted of silica gel powder (SG), silica gel mixed with eggshell powder (SG-ES) and a mixture of silica gel with sand from the western Iraqi desert (SG-SI). The samples were milled by using an electrical mixer and a ball mill, followed by a drying step. In addition, desert sand was acid-treated in order to remove impurities. The structure and chemical composition of the samples were investigated by X-ray diffraction (XRD), a scanning electron microscopy technique equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), a low-temperature nitrogen adsorption (BET) technique, thermo-analytical (TG/TGA) measurements and Fourier-transformed infrared spectroscopy (FTIR). The previously mentioned materials were tested to remove methylene blue from an aqueous solution. The adsorption experiments were monitored by ultraviolet-visible (UV-Vis) spectrophotometry and showed that SG and SG-ES gave promising results for the methylene blue removal from water. After 40 min of treatment of the aqueous solution containing 10 mg/L of MB at room temperature, the tested SG, SG-ES and SG-SI materials were found to have 86%, 80% and 57% dye adsorption efficiency, respectively. Taking into consideration not only the adsorption activity of the studied material but their availability, cost and concepts of cleaner production and waste minimization, the developed silica gel with eggshell can be considered as a good, cost-effective alternative to commercially available activated-carbon-based adsorbents. Different kinetic and isotherm models were fitted to the experimental results. A pseudo-second-kinetics-order model revealed high correlation fitting, while the Freundlich model was found to appropriately describe the adsorption isotherm. The thermal stability during the possible regeneration process of the SG-ES adsorbent mixture and its interaction mechanism with cationic dye was discussed.

Keywords: adsorption; eggshell; low-cost adsorbent mixture; methylene blue removal; sand; silica desiccant.

Grants and funding

This research received no external funding.