This work presents a novel hydrothermally aided sol-gel method for preparation of mesoporous silica nanoparticles (MSNs) with a narrow particle size distribution and varied pore sizes. The method was carried out in alkaline media in presence of polyethylene glycol (PEG) and cetyltrimethylammonium chloride (CTAC) as dual templates and permitted the synthesis of spherical mesoporous silica with a high surface area (1011.42 m²/g). The MSN materials were characterized by FTIR, Thermogravimetric (TG), Nitrogen adsorption and desorption and Field emission scanning electron microscopic analysis (FESEM). The materials feasibility as solid phase adsorbent has been demonstrated using cationic dyes; Rhodamine B (RB) and methylene blue (MB) as models. Due to the large surface area and variable pore width, the adsorption behaviors toward cationic dyes showed outstanding removal efficiency and a rapid sorption rate. The adsorption isotherms of RB and MB were well-fitted to the Langmuir and Freundlich models, while the kinetic behaviours adhered closely to the pseudo-second-order pattern. The maximum adsorption capacities were determined to be 256 mg/g for MB and 110.3 mg/g for RB. The findings suggest that MSNs hold significant potential as solid-phase nanosorbents for the extraction and purification of dye pollutants, particularly in the analysis and treatment of effluents containing cationic dyes.

The accurate determination of trace metals in aqueous matrices necessitates robust sample preparation techniques that enable selective preconcentration of analytes while ensuring compatibility with subsequent instrumental analysis. Dispersive solid-phase extraction (d-SPE), a suspension-based variant of conventional solid-phase extraction (SPE), facilitates rapid sorbent–analyte interactions and enhances mass transfer efficiency through direct dispersion of the sorbent in the sample solution. This approach offers significant advantages over traditional column-based SPE, including faster extraction kinetics and greater operational simplicity. When supported by appropriately engineered sorbents, d-SPE exhibits considerable potential for the selective enrichment of trace metal analytes from complex aqueous matrices. In this work, a fibrous silica-based chelating material, DSA-KCC-1, was synthesized by grafting 3,5-Di-tert-butylsalicylaldehyde (DSA) onto aminopropyl-modified KCC-1. The dendritic KCC-1 scaffold enables fast dispersion and short diffusion pathways, while the immobilized phenolate–imine ligand introduces defined binding sites for transition-metal uptake. Characterization by FTIR, TGA, BET, FESEM/TEM, XRD, and elemental analysis confirmed the successfulness of functionalization and preservation of the fibrous mesostructured. Adsorption studies demonstrated chemisorption-driven interactions for Pb(II) and Co(II) from water, with Langmuir-type monolayer uptake and pseudo-second-order kinetic behavior. The nano-adsorbent exhibited a markedly higher affinity for Pb(II) than for Co(II), with maximum adsorption capacities of 99.73 and 66.26 mg g⁻¹, respectively. Integration of the DSA-KCC-1 nanosorbent into a d-SPE–ICP-OES workflow enabled the reliable determination of trace levels of the target ions, delivering low limits of detection, wide linear calibration ranges, and stable performance over repeated extraction cycles. Analysis of NIST CRM 1643d yielded results in good agreement with the certified values, while the method demonstrated high tolerance toward common coexisting ions. The combined structural features of the KCC-1 support and the Schiff-base ligand indicate the suitability of DSA-KCC-1 for d-SPE workflows and demonstrate the potential of this SPE format for selective preconcentration of trace metal ions in aqueous matrices.

Aromatic amines such as 3-chloroaniline (3-CA) are toxic, persistent, and environmentally relevant water contaminants. Their reliable determination in aqueous systems has therefore become increasingly important. The monitoring of trace levels of these pollutants in complex water matrices typically necessitates a preconcentration step, most achieved via solid-phase extraction (SPE). However, conventional SPE sorbents often suffer from limited surface reactivity and slow adsorption kinetics, which compromise their performance at ultra-low concentrations. In contrast, nanomaterials offer a promising upgrade due to their high surface area, tunable chemistry, and rapid mass transfer behavior. In this work, mesoporous silica nanoparticles (MSNs) were synthesized via a green sol–gel route from sodium silicate precursor using polyethylene glycol template and then chemically functionalized with bisphenol A (BPA) to produce BPA-MSNs with π-rich and hydrogen-bonding active sites. Characterization using XRD, BET, FTIR, SEM/EDX, and TGA confirmed the successful synthesis and surface modification of the nanosorbent. BPA-MSNs achieved a maximum adsorption capacity of 30.2 mg/g toward 3-CA, fitting Langmuir and Jovanovic isotherm models. Kinetic analysis followed a pseudo-first-order model, indicating physisorption enhanced by π–π stacking and hydrogen bonding. The optimized dispersive SPE (D-SPE) method allowed a low detection limit (LOD = 0.016 mg/L), recovery of 73–85%, and precision below 5.3% RSD in tap, bottled, synthetic municipal wastewater and groundwater samples. The sorbent retained >90% efficiency over five reuse cycles, demonstrating strong potential as a reusable nanosorbent for preconcentration and remediation of aromatic amines in and treatment water analysis.

Mesoporous silica nanoparticles (MSNs) are promising nanomaterials for many applications, including water remediation, owing to their high surface area, tunable mesoporosity, and modifiable silanol-rich surfaces. However, their conventional synthesis often relies on costly tetraethyl orthosilicate (TEOS), cationic surfactants, organic solvents, and energy-intensive hydrothermal processing. Herein, a facile sustainable room-temperature sol–gel route is reported using inexpensive sodium silicate as the silica source, L-ascorbic acid as a mild biodegradable acid catalyst, and a binary nonionic surfactant system, Triton X-100/polysorbate 80, as the structure-directing template. The method replaces alkoxysilanes and hazardous cationic templates and eliminates external heating. It enables the production of uniform spherical MSNs with a locally ordered mesoporous structure, high specific surface area up to 551.5 m² g⁻¹, and large pore volume up to 1.98 cm³ g⁻¹. The adsorption capability of the optimized MSNs as nano-adsorbents was demonstrated using amoxicillin (AMX) as a model pharmaceutical contaminant. The optimized sample showed maximum AMX uptake at pH 5.0, followed pseudo-second-order kinetics, and fitted the Langmuir isotherm with a monolayer capacity of 91.3 mg g⁻¹. In spiked water matrices, the optimized MSNs recovered 88.5% and 84.4% of AMX from tap water spiked at 10 and 50 mg L⁻¹, respectively, and 83.5% and 81.0% from synthetic municipal wastewater spiked at the same concentrations, with RSD values below 5%. The adsorbent further retained 94% of its initial capacity after five adsorption–desorption cycles. This work establishes a scalable green route for producing high-quality MSNs and demonstrates the feasibility of the resulting silanol-rich mesoporous nano-adsorbents for pharmaceutical micropollutant removal, while also indicating their potential suitability as carrier platforms for drug-delivery applications.

The transition from conventional silica nanoparticle (SiNP) production based on purified alkoxysilanes and high-temperature flame hydrolysis of silicon tetrachloride to renewable and waste-derived silicon resources requires more than precursor substitution. It requires a mechanistic understanding of how feedstock mineralogy, silicon speciation, impurity chemistry, and processing history propagate through dissolution, nucleation, condensation, gelation, aging, drying, and pore evolution to determine material performance, environmental burden, and manufacturing feasibility. Although previous reviews have established the technical feasibility of producing silica from secondary resources, their predominant organization by feedstock, synthesis route, or application provides limited ability to explain why nominally similar processes generate materials with markedly different structural and functional properties. This review addresses these through a resource-pull, feedstock-to-function framework that links resource chemistry and process design to critical material attributes, application-specific specifications, sustainability, and scale-up requirements. Agricultural residues, industrial by-products, geothermal resources, waste glass, and fluorosilicate streams are critically compared according to silicon form and phase, reactivity, impurity profile, compositional variability, purification demand, and attainable product quality. Particular attention is given to waste-derived alkaline silicate systems, in which molecular, oligomeric, and colloidal silica coexist and therefore require characterization beyond bulk SiO₂ concentration. Established and emerging processing strategies, including controlled combustion and alkaline extraction, alkali fusion, ambient-pressure drying, microwave and mechanochemical activation, biogenic and biomimetic templating, and continuous processing, are evaluated according to their mechanistic effects, technological maturity, structural control, and demands for energy, reagents, water, solvents, effluent treatment, and capital. Across these routes, gelation and aging emerge as critical transfer stages through which feedstock composition is translated into network connectivity, pore architecture, shrinkage behavior, and ultimately functional performance. Evidence from secondary-source aerogels further shows that properly controlled waste-derived systems can attain BET surface areas of approximately 350–500 m² g⁻¹, within the textural range of many alkoxide-derived materials, indicating that feedstock variability, impurity management, and process control are more important constraints than an inherently lower performance ceiling. On this basis, this review proposes a minimum evidence framework comprising feedstock traceability, intermediate-speciation and colloidal characterization, silicon mass balance, gelation and aging metrics, application-specific qualification criteria, performance-normalized life cycle and techno-economic assessment, process analytical control, and staged pilot validation. Collectively, these principles provide a mechanistically grounded basis for moving sustainable silica synthesis beyond isolated proof-of-concept demonstrations toward reproducible, scalable, application-matched, and commercially credible manufacturing platforms.

The development of reusable nanomaterials for the extraction of trace-metals from complex matrices remains challenging because strong metal-chelating functionalities often hinder desorption and regeneration, whereas weaker binding sites compromise selectivity and enrichment efficiency. This limitation has been addressed by designing a ligand-engineered fibrous mesoporous silica nanomaterial (Van-KCC-1) via the integration of the unique structural features of KCC-1 with an o-vanillin-derived Schiff-base chelator. The material was synthesized throughout the chemical grafting of 3-aminopropyltriethoxysilane (APTES) onto fibrous mesoporous silica KCC-1, followed by condensation with 3-methoxy-2-hydroxybenzaldehyde (o-vanillin). The successfulness of functionalization and Schiff-base formation were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The radially oriented fibrous channels of KCC-1 provide a highly accessible surface that remains available for interaction with the targeted ions even after chemical modification. This architecture facilitates rapid mass transfer and efficient utilization of binding sites, while the incorporated Schiff-base ligand introduces imine, phenolic, and methoxy donor groups capable of selectively and reversibly coordinating Ni(II) and Cd(II). The resulting balance between adsorption strength and desorption efficiency enables both effective metal capture and sorbent reusability. More importantly, the study demonstrates how KCC-1 can serve as a versatile nanosilica scaffold for the incorporation of tailored chelating ligands without sacrificing structural accessibility. The functionalized nanomaterial was evaluated as a dispersive solid-phase extraction (DSPE) sorbent coupled with inductively coupled plasma optical emission spectrometry (ICP-OES). Under optimized conditions, linear ranges of 0.035–50 μg L⁻¹ for Ni(II) and 0.058–50 μg L⁻¹ for Cd(II) were obtained, with limits of detection of 0.011 and 0.019 μg L⁻¹, respectively. The method exhibited excellent precision (relative standard deviation ≤ 3.6%) and recoveries of 92.00–98.83% in certified reference materaisl (NIST CRM 1643d), mineral water, tap water and synthetic wastewater. In addition, the nanochelator has retained more than 87% of its initial sorption efficiency after six adsorption–desorption cycles and showed minimal interference from common coexisting ions. These findings establish Van-KCC-1 as an efficient, selective, and reusable DSPE sorbent in the determination of trace-metals while highlighting the broader potential of fibrous mesoporous silica KCC-1 as a platform for the rational design of next-generation chelated nanomaterials.