Rocks as a sustainable resource mSiO2: Extraction, characterisation, and use for heavy metals removal from wastewater by adsorption process

Wastewater from various sources can release large amounts of chemical pollutants and related substances into the environment. There is an immediate need for methods to purge water and wastewater of contaminants; one possible strategy is to employ matrix-stabilized nanoparticles for adsorption-based pollutant removal. Mesoporous silica (mSiO2) can be derived from natural sources as a cost-effective alternative to industrial products. Natural minerals such as porcelainite, kaolinite, shale, and diatomite contain silicon dioxide (SiO2), making them promising raw materials for the manufacture of mesoporous silica. Mesoporous silica is characterized by a highly ordered pore structure, with diameters ranging from 2 to 50 nm, an excellent surface area, and a slimming structure. Recent studies have demonstrated the adsorption capacity of mSiO2, particularly modified varieties, for removing toxic metal ions such as lead (Pb2+), cadmium (Cd2+), and chromium (Cr3+), even at low concentrations. These ions pose significant environmental risks due to their bioaccumulative nature and persistence in aquatic environments. Therefore, in simple terms, matsorption is a cost-effective, simple, and efficient method that is comparable to other techniques such as reverse osmosis, membrane filtration, precipitation, oxidation-reduction, and ion exchange. The mesoporous silica (mSiO2) was characterized using FTIR, FESEM, and XRD analyses. Fourier transform infrared (FTIR) spectroscopy has been widely used to characterize the functional properties of both tattoo chemicals and the distinctive features of military compounds. A strong short-duration stretching band at 1000 cm-1, attributed to silicon-oxygen vibrations, is the bandgap location of silicon dioxide. This demonstrates the fineness of the prepared material. The XRD pattern of pure silica (mSiO2) showed a strong stretch at 2𝜃 = 2.2◦ (100), spanning two stretches at 2𝜃 = 3.7◦ (110) and 4.3◦ (200). These lines indicate the hexagonal mesoporous structure of mSiO2. FESEM images showed that mSiO2 has a uniform surface composed of densely packed spherical particles. The test materials were evaluated for the removal of Pb2+, Cd2+, and Cr3+ ions, with removal efficiencies of 97.8% for Pb2+, 98% for Cd2+, and 99.6% for Cr3+ ions. Manufactured silica effectively decomposes water under various conditions, with optimal elimination achieved at pH 8, a contact time of 60 minutes, and a temperature of 298.