Mechanism Of Dye Adsorption Research Articles

Experimental and DFT theoretical study for understanding the adsorption mechanism of toxic dye onto innovative material Fb-HAp based on fishbone powder

The massive production of liquid discharges from the textile industry represents a global challenge based primarily on maintaining the equilibrium between ecological safety and commercial gain. In this regard, the physicochemical treatment of fishbone powder leads to hydroxyapatite (Fb-HAp) which is an innovative nanocomposite with effective morphology and specific surface area for the removal of the toxic dye Brilliant Green (BG) in an aqueous solution. The maximum adsorption capacity of BG on the Fb-HAp adsorbent’s surface is 49.1 mg g−1. The kinetics and isotherm of BG dye adsorption on Fb-HAp are best represented by the pseudo-second order’s equation and Langmuir's model, while the thermodynamic parameters show that the reaction is physical, feasible, spontaneous, and endothermic. The adsorption of BG on Fb-HAp experimental values were consistent with the values predicted by the response surface methodology and lead to a maximum removal rate of 99.87% under the conditions of pH 12, adsorbent dose 1 g L−1, and dye’s concentration 10 mg L−1. Quantum chemical calculations were executed using density functional theory (DFT) calculations at B3LYP 6-31G (d,p) to correlate their electronic properties with the experimental results. Based on the high electrophilicity values, low electronegativity, and Monte Carlo results, it is found that the basic form of the BG dye has a large overlap with the Fb-HAp adsorbent compared to the acid form. The low cost of the Fb-HAp material ($1.384 per gram) and its regeneration cycles show that it is environmentally friendly and very effective for dye removal in the textile industry.

Highly effective adsorption of organic dyes from aqueous solutions on longan seed-derived activated carbon

In this study, longan seeds - an agricultural by-product was used to fabricate activated carbon (LSAC) through two-step pyrolysis with pre-carbonization at low temperature in the first step and then activation by H3PO4. LSAC with large surface area and porous structure exhibits an excellent capacity of absorption towards both cationic dyes (methylene blue (MB), rhodamine-B (RhB)) and anionic dyes (methyl orange (MO), congo red (CR)). Experimental data can be described well by the pseudo-second kinetic model. The maximum adsorption capacity based on Langmuir isotherm model was found as 502.84; 397.77; 464.66 and 350.64 mg.g−1 for MB, RhB, MO and CR, respectively. The adsorption of MB, RhB and CR on LSAC is spontaneous and endothermic, while that for MO is spontaneous but exothermic. Furthermore, the adsorption mechanism of dyes on LSAC was also studied showing that it can occur by electrostatic interaction, hydrogen bonding, the filling of pores involving the interaction between dye ions with specific functional groups such as −OH, −COOH, −NH2 and −PO43- on the LSAC surface. These results suggest that LSAC material may be envisaged as a promising adsorbent for treatment of wastewater in textile industries.

Correction to the thermodynamic calculation using the Langmuir isotherm model by Saeed et al. (2022)

The thermodynamic parameters are usually used to analyze the spontaneity, thermal and random change of the adsorption process, therefore, it is important to obtain these parameters accurately. Recently, Saeed et al. (2022) published a high academic paper to reveal the adsorption properties and mechanism of dyes onto the chitosan composite of the iron metal-organic framework (CS/MOF-235). However, the thermodynamic parameters of ΔG and ΔS need to be corrected because their results affected the analyzed conclusions. In the present study, the thermodynamic parameters were recalculated by using the correct method through the Langmuir isotherm model. The recalculated thermodynamic parameters indicated that the change in free energy (ΔG) for the removal of methylene blue (MB) and methyl orange (MO) onto CS/MOF-235 is negative but not positive, meaning that the adsorption of dyes (MB and MO) is spontaneous but not non-spontaneous. The change in entropy (ΔS) is positive but not negative, implying that the randomness increases but not decreases during the adsorption process. The enthalpy (ΔH) maintained negative value and the entropy (ΔS) obtained positive value indicate that both of them are the driving forces of the adsorption.

Preparation of Templated Materials and Their Application to Typical Pollutants in Wastewater: A Review.

As the pollution and destruction of global water resources become more and more severe, the treatment of wastewater has attracted significant attention. The template method is a synthetic method in which the template is the main configuration to control, influence, and modify the morphology as well as control the dimensions of the material, thus achieving the properties that determine the material. It is simple, highly reproducible, and predictable, and more importantly, it can effectively control the pore structure, size, and morphology of the material, providing a novel platform for the preparation of adsorbent materials with excellent adsorption properties. This review focuses on the classification of the templates according to their properties and spatial domain-limiting capabilities, reviews the types of hard and soft template materials and their synthetic routes, and further discusses the modulation of the morphological structure of the materials by the introduction of templates. In addition, the application and adsorption mechanisms of heavy metal ions and dyes are reviewed based on the regulatory behavior of the template method.

New insights into the selective adsorption mechanism of cationic and anionic dyes using MIL-101(Fe) metal-organic framework: Modeling and interpretation of physicochemical parameters

In the current study, iron-based metal organic framework (MOF) MIL-101(Fe) was successfully prepared via a facile solvothermal method. The as–synthesized MIL-101(Fe) was characterized by XRD, FE-SEM, FTIR, TGA and zeta potential techniques, and then employed as an adsorbent for methyl orange (MO) and methylene blue (MB) dyes. The adsorbed quantities of MO (1067 to 831 mg/g) were higher than those of MB (402 to 353 mg/g) indicating the high selectivity of MIL-101(Fe) towards the anionic dye at all temperatures (20–60 °C). Adsorption processes of MO and MB followed the pseudo-second order kinetics and the Langmuir equilibrium model. The interaction mechanism at a molecular level was analyzed and deeply interpreted via the advanced multilayer adsorption model. Steric parameters indicated that MO molecular aggregation (n) was 0.95–1.33 thus signifying the presence of multi–docking and multi–interactions mechanisms. The aggregated number of MB was superior to unity (i.e., n = 1.17–1.78) suggesting a vertical adsorption position and a multi-interactions mechanism at all operating temperatures. The density of MIL-101(Fe) active sites (DM = 77.33–52.38 mg/g for MB and 149.91–107.07 for MO) and the total adsorbed dye layers (Nt = 3.12–2.49 for MB and 5.36–3.67 for MO) resulted in improving the adsorption capacities of MO dye. The adsorption energies ranged from 8.89 to 33.73 kJ/mol and they displayed that MO and MB uptake processes were exothermic controlled by physical interactions at all temperatures. Regeneration results indicated that this adsorbent can be reutilized without a significant loss in its removal efficiency after five adsorption-desorption cycles. Overall, the adsorption capacity, chemical stability, and regeneration performance of MIL-101(Fe) support its application as a very promising adsorbent for the removal of organic hazardous pollutants from water.

Synthesis, Swelling Characteristics, and Dye Adsorption Mechanism of a New Stimuli-Responsive Cationic Hydrogel

In this study, a new multi-stimulus cationic copolymer hydrogel was developed by bulk photo-polymerization of N-acryloyl-N’-propyl piperazine (AcrNPP) and poly (ethylene glycol) methacrylate (PEGMA) with ethylene glycol dimethacrylate (EGDMA) as crosslinker. The effect of multiple external stimuli, concentration of monomers, and equilibrium swelling of the hydrogels was studied in detail. The gels swelled in acidic solutions due to protonation of tertiary amine in the piperazine ring, and de-swelled in basic solutions. The presence of PEGMA in the hydrogel enhanced the swelling and imparted water-responsive property, leading to disintegration at high concentration of 49.85%. The hydrogel was evaluated as an adsorbent for the removal of an anionic dye, Congo red (CR) from water. The dye uptake capacity of the hydrogel increased with increase in the initial dye concentration. Interestingly, the swelling ratio of the hydrogel decreased at high dye concentration due to the formation of additional physical crosslinks within the hydrogel matrix. The dye uptake capacity of the hydrogel decreased with increasing temperature due to the negative-temperature responsive property of the hydrogel. The time-dependent adsorption data was fitted with seven kinetic models. Pseudo second-order model best described the kinetics of adsorption process, and the adsorption of CR onto the hydrogel could be very well described with phase-boundary controlled models. The adsorption was a multistep process with surface adsorption followed by intraparticle diffusion.

Kinetic, equilibrium, adsorption mechanisms of cationic and anionic dyes on N-doped porous carbons produced from zeolitic-imidazolate framework

Kinetic, equilibrium, adsorption mechanisms of cationic and anionic dyes on N-doped porous carbons produced from zeolitic-imidazolate framework

Insights into the Ph Dependency and Adsorption Mechanism of Ionic Dyes Onto Phosphoric Activated Biochar

Insights into the Ph Dependency and Adsorption Mechanism of Ionic Dyes Onto Phosphoric Activated Biochar

A novel nano-hybrid carbon architecture as chemo sensor for natural hazards: Active adsorption of Rose Bengal dye and detection of hazard pollutants at ppb level

A nano-hybrid metallic carbon-based architecture with fascinating new properties has been developed. MOs@CNT hybrid is designed using carbon nanotubes (CNTs) and metal oxides (MOs) by hydrothermal synthesis. FTIR, SEM, TEM, PXRD and TGA analysis were used to characterize MOs@CNT nanomaterial. MOs@CNT is employed for the adsorption of rose bengal (RB) showing excellent removal capacity (245.6 mg g−1) as compared to pristine MOs (48.8 mg g−1) at 298 K. Further the mechanism of dye adsorption is also proposed. Interestingly, this nanomaterial has a high sensing activity for nitroaromatic compounds (NACs) and chromium Cr(VI), where MOs@CNT 0.02g indicate a sensitive and selective luminescence quenching response to Cr(VI), nitrobenzene (NB), m-nitroaniline (m-NA) and p-nitroaniline (p-NA) in an aqueous medium with the average high quenching Ksv rate of 3.3 × 105 M−1 for NB and low detection limits up to 2.02 × 10−9 M also for NB. Therefore the new-fangled MOs@CNT emerges as a long-term multifunctional material for the detection of harmful NACs and Cr(VI) in an aqueous environment, moreover a great adsorbent for dyes.

A comprehensive review on the removal of noxious pollutants using carrageenan based advanced adsorbents

Rapid industrial development is associated with high discharge of toxic pollutants into the environment. The industries discharge their wastewater containing organic pollutants directly into the water system without treating them that has posed many serious threats to environmental protection. The use of bioadsorbents for the removal of such toxic pollutants from the waste water due to its simple synthesis, easy operation, effectiveness, and economic viability have emerged a new dimension in the wastewater treatment approaches. Various adsorbents have been prepared to examine their adsorption capacity against different adsorbates, but, to attain sustainability, biocompatibility, and biodegradation, bio-adsorbents have been found to won the battle. Seaweed derived polysaccharide; Carrageenan (CR) has been proven to be an excellent adsorbent for the wastewater treatment. It has been successfully modified with various components to form CR based-magnetic composites, hydrogels, nanoparticle modified CR composites and many others to enrich and diversify its properties.In this review, we have explained the adsorption behaviour of various carrageenan based adsorbents for the removal of different dyes. The influence of various parameters such as the effect of initial concentration, adsorbent dosage, contact time, pH, temperature, and ion concentration on dye adsorption is well explained. This paper also summarizes the structure, morphology, swelling ability, and thermal stability of carrageenan. The data also expounds on the adsorption capacity, kinetic model, isotherm model, and nature of the adsorption process. Different types of solvents are used for the regeneration and reusability of carrageenan adsorbents and their regeneration studies and desorption efficiency is well-explained. The adsorption mechanism of dyes onto carrageenan based adsorbents has been well described in this review. This review provides a deep insight about the use of carrageenan based adsorbents for the wastewater treatment.

Molecular dynamics and quantum simulation of different cationic dyes removal from contaminated water using UiO-66 (Zr)-(COOH)2 metal–organic framework

Metal organic frameworks (MOFs) especially benzene-1,4-dicarboxylic acid-functionalized UiO-66 (UiO-66-(COOH)2) with distinguished properties are great candidates for dyes removal from wastewater. In the current work organ-metal with anion groups, UiO-66-(COOH)2 (MOF/(COOH)2), was selected to adsorb four toxic cationic dyes from aqueous media. The quantum chemical calculations and molecular dynamic simulation were used to evaluate the adsorption mechanism of four toxic cationic dyes (malachite green (MG), methylene blue (MB), toluidine blue (TB) and crystal violet (CV)) on the MOF/(COOH)2 in the presence of water molecules. The optimized geometry of all structures was obtained through Dmol3 module. According to the obtained results the highest adsorption energy was obtained for CV-water-MOF/(COOH)2 configuration, while the MB-water-MOF/(COOH)2 had the lowest adsorption energy. Also, the molecular electrostatic potential maps and frontier molecular orbitals (FMO) were achieved for all configurations. The HOMO and LUMO as well as energy gap (ΔEGAP) indicated that the highest adsorption affinity was belong to CV-water-MOF/(COOH)2 configuration. Accordingly, the increasing of ΔEGAP was in the following order: CV-water-MOF/(COOH)2 < MG-water-MOF/(COOH)2 < TB-water-MOF/(COOH)2 < MB-water-MOF/(COOH)2.The quantum chemical descriptors such as chemical potential, electronegativity, nucleophilicity and electrophilicity index, chemical softness and hardness were obtained from HOMO and LUMO energy levels. Consequently, the results demonstrated that the chemical reactivity, softness, and polarizability of CV dye were higher compared to other studied dyes. The results of this theoretical revealed that UiO-66-(COOH)2 as an acidic group functionalized MOF is highly recommended for removal of cationic dyes. Molecular dynamic simulations can be a very useful approach to make a brighter insight about the mechanism of cationic dyes adsorption on the MOF adsorbent and very effective from perspective of time and experimental costs.

Efficient adsorption and facile photocatalytic degradation of organic dyes over H-bonded proton-transfer complex: An experimental and theoretical approach

In this work, a proton-transfer complex namely, 5-hydroxy-isophthalic acid (IPA) with 3-((4-(3-isocyanobenzyl) piperazine-1-yl) methyl) benzonitrile (PBN) (1) was synthesized and employed to study the adsorption and photocatalytic properties. Interestingly, it exhibited selective adsorption of cationic dyes such as Methyl Red (MR) and Methylene Blue (MB). Subsequently, the photocatalytic potential of complex 1 was also explored towards facile degradation of MR and MB dyes under UV-light illumination. The dye adsorption activity of complex 1 could be attributed to charge transfer and the existence of an intricate array of non-covalent interactions between them, whereas efficient charge separation between HOMO-LUMO is pivotal for photo degradation of dyes under UV-light illumination. Moreover, the kinetic studies reveal both adsorptions as well as photocatalytic degradation of dyes, followed the pseudo-first-order mechanism. The density functional theory (DFT) calculations were used to validate the dye adsorption mechanism. However, the alterations in the electronic property were noticed by comparing the theoretical results before and after the adsorption, showing that adsorption is a physical process.

Carbon nanotube incorporated eucalyptus derived activated carbon-based novel adsorbent for efficient removal of methylene blue and eosin yellow dyes

Carbon nanotube (CNT) incorporated eucalyptus derived activated carbon-based novel adsorbent is synthesized by a novel route. This adsorbent is investigated for the removal of two different dyes; methylene blue (MB) and eosin yellow (EY) from the waste water. The effect of pH, adsorbent dose, contact time and initial concentration, has been used to measure the dye removal efficiency of the adsorbent. Langmuir isotherm, Freundlich isotherm and D-R isotherm models were used to fit the experimental dye adsorption data, with the D-R model providing the best fit. The maximum adsorption efficiency of adsorbent for MB and EY removal is 49.61 and 49.15 mg/g, respectively. Reaction kinetics studies were also established to further investigate the dye adsorption mechanism. It is observed that pseudo second order model define the reaction kinetics involved in the reaction. This activated carbon adsorbent based on CNTs is shown to be highly promising for water decontamination applications.

Study on anionic and cationic dye adsorption behavior and mechanism of biofilm produced by Bacillus amyloliquefaciens DT

Biofilm produced by Bacillus amyloliquefaciens DT was reported to be able to remove crystal violet from water. However, there is no report on the ability of biofilm to remove other dyes. Here, we used methyl blue (MB; anionic) and malachite green (MG; cationic) as model dyes and investigated the behaviors and mechanisms of their adsorption by bacterial biofilm. Biofilm surface morphology, functional groups, and chemical constituents were characterized. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy results demonstrated that the relevant adsorptive functional groups were CN bond/NH3− and CN bond/OP(C)O− for MB and MG adsorption, respectively. Isothermic and kinetic models revealed that biofilm adsorbs MB heterogeneously via chemisorption and intraparticle diffusion. In contrast, biofilm adsorbs MG mainly by physical interaction. Biofilm adsorption capacities were substantially higher than those for most other adsorbents. Hence, biofilm is promising as an anionic and cationic dye adsorbent for wastewater treatment.

Adsorption of methylene blue from aqueous solution on activated carbons and composite prepared from an agricultural waste biomass: A comparative study by experimental and advanced modeling analysis

Activated carbons and MOF-based composite were prepared from the ashitaba biomass and they were applied and compared in the adsorption of methylene blue from aqueous solution. Surface chemistry of these adsorbents was characterized with different analytical techniques and results were used to analyze the corresponding adsorption interactions. Statistical physics calculations were performed to interpret the physicochemical parameters involved in the dye adsorption mechanism. Results showed that the dye adsorption with activated carbons was endothermic, while an exothermic dye removal was observed with the MOF-activated carbon composite. Dye adsorption mechanism was a multimolecular process mainly for ashitaba-based activated carbons where electrostatic interactions, van der Waals forces and hydrogen bonding were present. In particular, the activated carbon functionalized with a surfactant outperformed other adsorbents prepared with the ashitaba biomass thus showing adsorption capacities higher than 400 mg/g. This adsorbent is promising for its application in the treatment of wastewaters polluted by this and other dye molecules.

Adsorption of azo dye Congo red on the Sn-doped TiO2 surface

In this paper, the effect of SnO2 impurity on the surface charge and adsorption properties of TiO2 samples is investigated. The experimental value of the zero charge point for TiO2 with 3%, 6% and 12% of SnO2 equals 3.53, 3.97 and 3.2, respectively. The adsorption activity of the samples was studied on model solutions of the anionic dye – Congo red. The maximum adsorption capacity (qexp) equals 24.6 mg/g for 3Sn/TiO2, 25.0 mg/g for 6Sn/TiO2 and 39.1 mg/g for 12Sn/TiO2. Langmuir, Freundlich, and Dubinin-Radushkevich models were used to describe the adsorption mechanism of Congo red dye on the surface of Sn/TiO2 samples. Based on the results of the studies of Congo red adsorption by the surface of titanium dioxide doped with Sn, all samples agree best with the Langmuir model. The correlation coefficients for the Langmuir isotherms are in the range of 0.9927 - 0.9996, while the values ​​of R2 for the Freundlich and Dubinin-Radushkevich isotherms are in the range of 0.721 - 0.8329 and 0.8283 - 0.9433, respectively. Experimental data obtained from adsorption isotherms show that the TiO2 sample containing 12% SnO2 is the most active. The best result of Congo red removal occurred at a concentration of Co = 5 mg/l (% of removed dye ≈ 83% for 12Sn/TiO2; 81% for 6Sn/TiO2 and 71% for 3Sn/TiO2). Therefore, the studied samples of TiO2 doped with SnO2 can be used as effective adsorbents of Congo red from aqueous solutions.

Dye Adsorption Mechanism of Glass Fiber-Reinforced Plastic/Clay Ceramics and Influencing Factors.

The effective reuse of waste glass fiber-reinforced plastic (GFRP) is desired. We previously produced porous ceramics by firing mixtures of crushed GFRP and clay in a reducing atmosphere and demonstrated their applicability as adsorbents for the removal of basic dyes from dyeing wastewater. However, the primary influencing factors and the dye adsorption mechanism have not been fully elucidated, and the adsorption of acidic and direct dyes has not been clarified. In this study, adsorption tests were conducted, and the effects of the firing atmosphere, specific surface area, type of dye, and individual components were comprehensively investigated. The results showed that reductively fired ceramics containing plastic carbide residue adsorbed basic dye very well but did not adsorb acidic dye well. The clay structure was the primary factor for the dye adsorption rather than the GFRP carbide. The mechanism for the basic dye adsorption appears to have been an increase in specific surface area due to the plastic carbide residue in the ceramic structure, which increased the ion exchange between the clay minerals and the dye. By adjusting the pH of the aqueous solution, the GFRP/clay ceramic also adsorbed considerable amounts of direct dye, so the mechanism was determined to be ion exchange with the calcium component of the glass fibers.

Green antimicrobial adsorbent containing grafted xanthan gum/SiO2 nanocomposites for malachite green dye

Recently, removal of synthetic dyes, especially cationic dye of malachite green (MG), and inhibition of the growth of pathogenic microorganism from drinking water have gained much interest due to their high toxic potency for aquatic biosystems. Herein, a new dye adsorbent with outstanding antibacterial activity was fabricated based on xanthan gum (XG) and SiO2 nanoparticles through ultrasonication followed by the crosslinking polymerization with vinyl imidazole monomer. The nano adsorbents were characterized with various techniques such as FTIR, XRD, SEM, EDX, and TEM. The nanocomposites were applied as a filter for discarding MG dye and killing the growth of bacterial strains such as E.coli and S.aureus which are considered as the common impurities for drinking water. The data revealed that a maximum adsorption capacity was recorded as 99.5% (Qmax = 588.2 mg/g) at optimum conditions including 10 mg nanocomposite, 10 mL of MG dye (450 ppm), pH = 7, the temperature of 30 °C, and the adsorption time was adjusted within 6 h. The process of dye adsorption was applied to the common isotherm models of Langmuir, Temkin, and Freundlich, and the findings showed that the adsorption behavior was well fitted with the Langmuir one (R2 = 0.9983). Moreover, different adsorption kinetic models such as pseudo-first order, pseudo-second order, and intra-particle diffusion were studied for understanding the mechanism of MG adsorption onto nanocomposite surface. It was found that both intraparticle diffusion and pseudo-first-order have participated evenly in the adsorption mechanism of MG dye. Ultimately, the as-prepared nanocomposites were tested against the growth of S. aureus, and E.coli manifesting a superior inhibition diameter as 23.5 ± 0.50, and 25.33 ± 0.47 mm against E.coli, and S. aureus, respectively. Therefore, our new XG-g-PVI/SiO2 adsorbent is a very promising adsorbent for the fast and efficient capture of dyes from aqueous solutions.

Adsorption of Organic Dyes on Magnetic Iron Oxide Nanoparticles. Part I: Mechanisms and Adsorption-Induced Nanoparticle Agglomeration.

This series of two papers is devoted to the effect of organic dye (methylene blue, MB; or methyl orange, MO) adsorption on the surface of either bare or citrate-coated magnetic iron oxide nanoparticles (IONPs) on their primary agglomeration (in the absence of an applied magnetic field) and secondary field-induced agglomeration. The present paper (Part I) is focused on physicochemical mechanisms of dye adsorption and adsorption-induced primary agglomeration of IONPs. Dye adsorption to oppositely charged IONPs is found to be mostly promoted by electrostatic interactions and is very sensitive to pH and ionic strength variations. The shape of adsorption isotherms is correctly reproduced by the Langmuir law. For the particular MB/citrated IONP pair, the maximum surface density of adsorbed MB seems to correspond to the packing density of an adsorbed monolayer rather than to the surface density of the available adsorption sites. MB is shown to form H-aggregates on the surface of citrate-coated IONPs. The effective electric charge on the IONP surface remains nearly constant in a broad range of surface coverages by MB due to the combined action of counterion exchange and counterion condensation. Primary agglomeration of IONPs (revealed by an exponential increase of hydrodynamic size with surface coverage by MB) probably comes from correlation attractions or π-stacking aromatic interactions between adsorbed MB molecules or H-aggregates. From the application perspective, the maximum adsorption capacity is 139 ± 4 mg/g for the MB/citrated IONP pair (pH = 4–11) and 257 ± 16 mg/g for the MO/bare IONP pair (pH ∼ 4). Citrated IONPs have shown a good potential for their reusability in water treatment, with the adsorption efficiency remaining about 99% after nine adsorption/desorption cycles.

Fabrication of a Nanoporous Silica Hydrogel by Cross-Linking of SiO2–H3BO3–Hexadecyltrimethoxysilane for Excellent Adsorption of Azo Dyes from Wastewater

This study reports a novel cross-linking approach to fabricate the hydrothermally neutralized silica hydrogel of SiO2-H3BO3-hexadecyltrimethoxysilane by grafting alkylsilane groups onto the nanoporous silica. The synthesized silica hydrogel possessed a large specific surface area of 51.3 m2g-1 and showed excellent dye adsorption capability of cationic dyes in neutral (pH 7) and alkaline (pH 9) medium from wastewater. The colloidal electrokinetic potential analysis revealed that the outstanding adsorption efficiency of cationic dyes over anionic dyes strongly relies on the surface charge of the hydrogels. Moreover, the hydrophobic interactions between the dye molecules and the hydrogels were studied, and it was found that the dye adsorption performance can be tuned by altering the concentration of hydrophobic reagents of the hydrogel. The dye adsorption mechanism was established, and the kinetic study suggested that the adsorption is a pseudo-second-order reaction. Adsorption isotherms at various equilibrium conditions fitted well with the Langmuir isotherm. Therefore, this strongly supports the promising and practical application of the prepared silica hydrogel. The recyclability of the hydrogel was studied, and it showed 90% adsorption efficiency by the regenerated gel up to 6 cycles, which has a high potential in wastewater treatment.