Synthesis of a SiO2-MgO composite material derived from yellow phosphorus slag with excellent malachite green adsorption activity

Abstract

There has been increasing attention devoted to the treatment of wastewater to eliminate organic dyes. Here, a composite material was developed using SiO2 matrix material obtained from yellow phosphorus slag and loaded with MgO, then examined for its ability to absorb the malachite green dye. The influence of a variety of variables, such as time, temperature, pH, and initial simulated effluent concentration, was investigated. These investigations demonstrated that when using this SiO2-MgO adsorbent, a maximum malachite green adsorption rate of 97.72 % was obtained, with precisely 115.64 mg g−1 of dye absorbed. Interestingly, the prepared SiO2-MgO was stable and regenerated successfully, exhibiting good performance throughout the four cycles. The specific surface area and pore size of the developed adsorbent composite material were found to be 352.76 m2 g−1 and 2–10 nm, respectively. Scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses revealed that electrostatic adsorption, dipole-dipole H-bonding, ion exchange, and Yoshida H-bonding interactions were among the mechanisms used by this SiO2-MgO composite to adsorb malachite green. Importantly, this adsorbent can be simply and efficiently produced, making it well-suited to lowering MgO utilization and raising SiO2 adsorption efficacy while allowing for greater yellow phosphorus slag utilization and the establishment of a novel solid waste treatment approach.