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Water from the industries contains various organic effluents which are needed to be removed. Photocatalysis is an efficient method to degrade organic effluents that contaminate water and harmfully affect the environment. This study presents the structural, optical characteristics, and photocatalytic activity of the CuO/MoS2 and their composite with gCN. The hydrothermal approach was employed to fabricate MoS2 nanoflowers, and the co-precipitation method to fabricate CuO. The composite with gCN was prepared successfully using an ultrasonication approach. The physio-chemical properties of fabricated photocatalysts were investigated by various characterization techniques. SEM analysis revealed the nanoflower morphology of the prepared MoS2 sample. The photocatalytic activity was examined by the photodegradation of methyl orange dye and phenol. CuO/MoS2@gCN photocatalyst showed 85.14 % degradation of methyl orange and 63.50 % degradation of phenol. Also, the rate constant of CuO/MoS2@gCN was found to be 0.051 min−1 for MO dye and 0.02 min−1 for phenol, which is higher than other synthesized samples. The scavenging experiment was carried out to identify the most photoactive species involved in the organic pollutants photocatalytic degradation. Electrons served as the primary photoactive species in photocatalysis. Consequently, it is concluded from the results that CuO/MoS2@gCN could be employed as an efficient photocatalyst for wastewater treatment.

The study aimed to establish a correlation between the photocatalytic degradation of Congo red (CR), Crystal violet (CV) dyes and Diclofenac sodium (DS) drug by copper, terbium substituted nickel ferrite (CuxNi1-xTbyFe2-yO4) and MXene (CTNF/MXene) composite where (x, y = 0.1). Terbium and copper doping reduced crystallite size, band gap energy, improve visible light absorption and impede electron-hole pair recombination. Superior complexation ability of terbium forces more pollutants to adsorb on the surface of photocatalyst and hence more degradation. Results indicated that MXene, acting as a co-catalyst, effectively lowered the charge recombination rates by electron trapping and enhanced the visible light absorption, improving the photocatalytic activity. CTNF/MXene composite exhibited greater rate constant and photocatalytic degradation of CR (91 %), CV (77 %) and DS (81 %) as compared to NF, CNF, TNF, CTNF. The increased surface area of CuxNi1-xTbyFe2-yO4 with MXene and reduced electron-hole pair recombination are possible factors for its successful use as photocatalyst.

Designing highly efficient and durable multicomponent heterostructured composites as catalytic materials for concomitant hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is highly desirable. Researchers all over the world are continuously working to develop such materials. Herein, CNTs wrapped CoFe2O4/CoFe LDH (CoF/CoFe LDH@CNTs) ternary composite is synthesized by hydrothermal and ultra-sonication routes. Numerous methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrical Mott-Schottky, and electrochemical impedance spectroscopy (EIS) are employed to study structure, morphology, flat band potential, and electrochemical properties of prepared samples. In terms of water splitting performance, CoF/CoFe LDH@CNTs composite showed predominant performance for both HER and OER activities, as compared to its analogs (CoF and CoF/CoFe LDH). Faster electron transfer is also exhibited by CoF/CoFe LDH@CNTs, as it possesses a lower Tafel slope. For OER, CoF/CoFe, LDH@CNTs require a small overpotential of 170 mV to reach a current density of 10 mA cm−2 in 1 M KOH, with a Tafel slope of 42 mV dec-1. Similarly, for HER an overpotential of 218 mV is required to drive 10 mA cm−2 with a small Tafel slope of 31 mV dec-1. Impedance studies show a small value of charge transfer resistance (Rct = 1.11 Ω) for CoF/CoFe, LDH@CNTs. Significant electrochemical performance for CoF/CoFe, LDH@CNTs for both half-reactions (OER and HER) is ascribed to the synergy among electrochemically active CoF and CoFe LDH, and a highly conductive network of CNTs. The present strategy improves the electrochemical performance of electrochemical systems relevant to energy applications.

Tungsten oxide (WO3), Iron and vanadium co-doped tungsten oxide (FeVWO3), and the composite of iron and vanadium co-doped tungsten oxide with graphitic carbon nitride (FeVWO3@g-C3N4) were prepared for the photocatalytic study. WO3 and FeVWO3 were synthesized by co-precipitation, and the composite FeVWO3@g-C3N4 was synthesized by an ultra-sonication approach. All the prepared materials were analyzed by different techniques. Structural study was done by XRD, functional group analysis by FTIR, and SEM was used for the morphological study of the nanoparticles. EIS measurements were done to investigate the electrical properties of fabricated materials. Photocatalysis was performed for the band gap analysis. Pendimethalin (PM) a herbicide and aspirin (pharmaceutical product) were used in photocatalysis and degraded by the prepared photocatalysts (WO3, FeVWO3, and FeVWO3@g-C3N4). WO3 and FeVWO3 have 2.62 eV and 2.34 eV Eg values of band gap, respectively. FeVWO3 has a lower Eg value than WO3. The decrease is due to the doping, and generation of further energy levels in the band gap of the pure sample, and these energy levels cause changes in the electronic structure of the sample. The composite shows a high degradation efficiency. The percentage degradation of pendimethalin and aspirin by FeVWO3@g-C3N4 was 82.26 % and 92.84 %. It is because of the presence of g-C3N4 which provides greater surface area for better degradation efficiency.

In this paper, wet-chemically synthesized hierarchical NiO microspheres and their exfoliated (ExC)-based nanocomposites (NiO/ExC) as electrodes for supercapacitor applications have been reported. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopic (SEM) techniques were used to characterize the as-synthesized products. The study of PXRD revealed that NiO exhibits a cubic phase. Morphological analysis showed a hierarchical micro-spherical structure of mesoporous NiO particles. The as-synthesized hierarchically porous NiO manifested a specific capacitance of 331 F/g with 50% capacitance retention. But, exfoliated carbon (ExC)-based nanocomposite (0.07 g NiO/0.003 g ExC) showed a particular capacitance of 815 F/g at the scan rate of 5 mV/s, with 79% retention in capacitance. High electrical conductivity and larger surface area arising from synergistic effects between NiO and exfoliated carbon resulted in a tremendous electrochemical response of NiO/ExC nanocomposites. The inclusion of the ExC further improves electrical impedance spectroscopic results by facilitating the charge transfer.

Ni-Al-Cd oxide nanostructures were fabricated by facile co-precipitation method and was embedded on CNTs by the ultrasonication method. The properties and structural features of prepared materials were analyzed by various techniques such as X-Ray diffraction, scanning electron microscopy, UV-visible spectroscopy and Fourier transform infrared spectroscopy. The synthesized nanomaterials were employed for degradation of methylene blue under sunlight and for antibacterial study. The photocatalytic results indicate that the ternary oxide of Ni-Al-Cd has a greater potential for degradation of methylene blue and other harmful compounds owing to possible heterojunction development. The photocatalytic degradation of ternary Ni-Al-Cd oxides/CNTs was 67.16% within 2 h. Moreover, photocatalytic activity was increased by carbon nanotubes. The results revealed that ternary oxides and their nanocomposite with CNTs have an excellent ability for photocatalytic degradation and showed better antibacterial activity than ternary oxides.

Pb1−4.75xNd0.5xNi4xZrO3 (where x = 0.00, 0.01, 0.02, 0.03, 0.04 and 0.05) nanocrystals were synthesized through the micro-emulsion, a wet chemical route. The prepared samples were annealed at 700°C for 3 h. Nanocrystalline samples were characterized by various techniques like XRD (X-rays diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (Scanning electron microscopy), dielectric properties, and dc-electrical resistivity. XRD analysis of synthesized nanocrystals confirmed the phase development of orthorhombic perovskite structure. The average measured size of nanocrystals was about 21 nm. Some other parameters like densities (bulk and X-rays) and porosity of the nanomaterials were also calculated from obtained XRD data. The obtained results showed the effect of dopant materials (Nd3+ and Ni2+ metal ions) incorporation. The FTIR spectra elucidated the intrinsic cations vibrations in the characteristic perovskite orthorhombic structure. The SEM results revealed that nano-grains were synthesized successfully and their average observed size was 60 nm. It was observed that with the addition of dopant material, the dielectric parameters like dielectric constant, loss factor, and conductivity were showed an overall decreasing trend. The average calculated value of the ac conductivity at the frequency of 3 GHz was observed as 1.45 × 10−2 (Ω-cm)−1. By using the current–voltage (I–V) characteristics, the dc-electrical resistivity was calculated in the range between 2.68 × 1010 and 4.82 × 1010 Ω-cm. The dc-electrical resistivity was increased with the increase of doping contents.

The current study is based on the synthesis and characterization of ZnO–NiO/rGO nanohybrid for photocatalytic degradation of organic pollutants. The physicochemical properties of synthesized products were estimated by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FESEM), and Ultraviolet–Visible spectroscopy. The diffraction data showed the formation of binary metal oxide nanocomposite, containing ZnO in hexagonal whereas NiO in the cubic crystalline phase. XRD results revealed that the calculated crystallite size of NiO and ZnO in the ZnO–NiO nanocomposite was

In the present study, stabilizer caged fluorescent rhodamine B mesoporous silica particles with special shapes were prepared. The prepared particles have a pore volume of 1.92 cm3/g and a pore diameter of 12 nm. The abundant hydroxyl functional groups of mesoporous silica are responsible for the superior loading capacity of target molecular specie. The appearance of bands due to –COOH, –CH3, –CH2, –NH etc. indicated that the fluorescent rhodamine B could be encaged with the stabilizer inside the mesoporous channels. The performance of mesostructured origami silica matrix was evaluated by in vitro release experiments. From the in vitro release results, this material is suggested to have appropriate features for almost no release at pH = 1.2 and very slow release at neutral pH value. The same material could be best employed at pH 4.5 and at high pH values. It is concluded that mesostructured origami silica matrix is a smart nano-platform and can be utilized for high retention of cargo molecules.

In this paper, adsorption of Congo red (CR) onto L-cysteine decorated with reduced graphene oxide/polyaniline composite at room temperature was investigated. The morphology and structure properties of as-prepared nanocomposite were verified by UV–visible spectroscopy (UV–visible), powder X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FTIR), scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) studies. Effect ofabsorbent dosage, contact time, initial dye concentration and temperature were studied and optimal conditions for the adsorption process of Congo red dye were found. The obtained results indicated that isotherms data fitted well to Langmuir model. While kinetics data fitted well to the pseudo-second-order kinetic equation and the adsorption process was generally governed via intra-particle diffusion. Thermodynamic data showed that adsorption process of CR was endothermic and spontaneous in nature. At optimal conditions, the maximum adsorption capacity of CR was calculated and found to be 56.57 mg/g, which shows that L-cysteine functionalized reduced graphene oxide/polyaniline based nanocomposite can be efficiently used for wastewater management.

A potential electrode material, besides the higher specific capacitance, should also exhibit superior cyclic stability and good rate capability. Here, we have fabricated urchin-like hierarchical Co3O4 nanoarchitecture directly on the Ni-foam (NF) by a scalable hydrothermal and post-sintering treatment. The as-fabricated Co3O4/NF electrode shows higher pseudocapacitance (PSCs) of 848 Fg−1 (at1 Ag−1) and good rate capability as it retains 84.6% of its initial PSCs (at 1 Ag−1) at 10 Ag−1. Furthermore, fabricated Co3O4/NF electrode also exhibits superior cyclic performance as it holds 95.7% of its initial PSCs after 5000 CV tests. The outstanding percentage coulombic efficiency of 99.1% at 10 Ag−1 also confirms the feasibility and cyclic-reversibility of the Faradic reaction. The observed superior capacitive behavior of Co3O4/NF electrode is accredited to its binder-free design, uniform architecture, and urchin-like open structure. These observed electrochemical results suggest that Ni-foam supported urchin-like hierarchical Co3O4 nanoarchitecture is the promising electrode material for high-performance hybrid supercapacitors applications.

In this work, we are reporting the facile synthesis of hierarchically porous CuO microspheres and their r-GO based nanohybrid as an electrode material for supercapacitor applications. The fabricated product was characterized by powder X-ray diffraction technique (PXRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis, and Brunauer–Emmett–Teller (BET) analysis. PXRD analysis showed the existence of the monoclinic phase of CuO. The compositional study of the synthesized product was completed via EDX analysis. The FESEM analysis confirmed the hierarchical porous micro-spherical architecture of the product with smaller CuO grain-size particles, quasi-microporous spindle-like nanosheets assembled by nano-grains, and their aggregation to mesoporous nature. The BET analysis revealed that the BET and Langmuir surface area of the hierarchically porous CuO microspheres was 60.02 m²/g and was 86.68 m²/g. Furthermore, the BET results also confirmed the mesoporous structure of the fabricated sample. The hierarchically porous CuO microspheres showed a specific capacitance of 402 F/g at 1 A/g with 75.4% capacitance retention whereas their r-GO based nanohybrid showed 712 F/g at 1 A/g with 96.9% capacitance retention. The greater electrochemical response of r-GO based nanohybrid was due to the greater surface area and higher electrcial conductivity arise from the synergistic effects between the novel structure and r-GO nanosheets. Moreover, apart from the condcutive matrix r-GO also behaves as a capacitive supplement and contributes toward the total capacitance of the nanocomposite. The electrical impedance spectroscopy (EIS) experiments reveal that the addition of the r-GO matrix also facilitates the charge transfer and improves the kinetics of the redox reaction. In short, it can be concluded that r-GO based hierarchically porous CuO microspheres found themselves as a potential candidate in the field of hybrid supercapacitors.

In this work, nanocrystalline NiDyxFe2-xO4 ferrites (0.0 ≤ x ≤ 0.1) were synthesized via co-precipitation route. The impact of Dy+3 substitution on the various properties has been investigated. Structural, electrical, spectral and magnetic parameters were measured by XRD (X-ray diffraction), I–V (current-voltage), FTIR (Fourier transform infrared spectroscopy) and VSM (vibrating sample magnetometer) respectively. Morphological analysis was done by FE-SEM (Field emission scanning electron microscope). The formation of a single-phase FCC cubic spinel structure was confirmed by XRD patterns. With the help of XRD data, bond lengths and ionic radii were also calculated. FTIR spectra showed the formation of two typical frequency bands (υ1 and υ2) which represent metal-oxygen (M–O) vibrations at octahedral (B) and tetrahedral (A) sites. EDX spectrographs confirmed elemental composition. The MH curves demonstrated a decrease in saturation magnetization (Ms) and Bohr magneton (nB). The coercivity (Hc) showed a non –linear behaviour while anisotropy constant first increased and then decreased with Dy-substitution. NiDy0.025Fe1.975O4 showed maximum coercivity (102.06 Oe).

A proficient, eco-friendly, and cost-effective catalyst for remediation of organic contaminants in the environment is a burning issue in recent decades. In the present study, the cobalt doped MnO (Co-MnO) photocatalyst was synthesized via cost-effective and environmentally friendly reverse micelle route. The X-ray diffraction (XRD) results confirmed the synthesis of well-defined cubic-phased MnO and Co-MnO. XRD structural parameters and Williamson-Hall plot of MnO and Co-MnO samples were also explained in detail. Optical band gap analysis revealed an enhanced red-shift of 2.16 eV for Co-MnO photocatalyst as compared to pristine MnO (2.81 eV). The remediation efficiency of pristine MnO and its cobalt doped sample was also was tested using an organic contaminant crystal violet (CV) dye. Excellent synergistic effects of adsorption and photocatalysis at normal conditions, simple degradation mechanism, impressive kinetic investigation, and the low dose utilization proved that the newly synthesized Co-MnO photocatalyst might have commercial applications for environmental applications.

Nanocomposites consisting of polyvinyl alcohol embedded with nanoparticles of Zn0.80Co0.1Ni0.1Fe2O4 and ZnFe2O4 were successfully synthesized by employing a facile two-steps process. The nanoparticles of Zn0.80Co0.1Ni0.1Fe2O4 and ZnFe2O4 were synthesized via a micro emulsion procedure and then embedded into a polyvinyl alcohol matrix by an ultrasound-assisted in-situ emulsion. The result showed that the prepared nanoparticles of Zn0.80Co0.1Ni0.1Fe2O4 & ZnFe2O4 diffuse homogeneously in a polyvinyl alcohol matrix, maintaining the particle shape and size of the Zn0.80Co0.1Ni0.1Fe2O4 nanoparticles. Transmission electron microscope images revealed that polyvinyl alcohol chains have encircled the Zn0.80Co0.1Ni0.1Fe2O4 & ZnFe2O4 nanoparticles. The interaction between the polyvinyl alcohol and the nanoparticles in the prepared nanocomposites was confirmed by Fourier-transform infrared spectroscopy via the shifting of bands revealed from the Fourier-transform infrared spectra. Dielectric studies explained the decreasing trend by varying concentrations of nanoparticles with a constant polymer concentration. The dielectric constant and dielectric loss both revealed a decreasing trend by varying the concentration of the nanoparticles with a constant polymer concentration. This occurred due to the grain boundary effect which becomes dominant at low frequencies. The Transmission electron microscope images result shows that polycrystalline Zn0.80Co0.1Ni0.1Fe2O4 & ZnFe2O4 nanoparticles with an average size of 10–15 nm were incorporated with PVA to form nanocomposites. Keywords: Nanocomposites, Polyvinyl alcohol (PVA), Ultrasound-assisted, In-situ emulsions

A facile strategy was used for the synthesis of nickel ferrite/zinc oxide (NiFe2O4/ZnO) nanocomposite via an ultra-sonication method and observed its recyclability and photostability with enhanced visible light-driven photocatalytic performance. The photo degradation activities of as-synthesized photocatalysts were investigated using various dyes including methylene blue, crystal violet and methyl orange under solar light irradiation. Prepared material degrades 49.2% methyl orange, 44.4% methyl blue and 41.3% crystal violet in 40 min. Further, the synergistic effect of nickel ferrite and zinc oxide can reduce the probability of recombination of charge carrier and boost the charge separation which leads to remarkable photocatalytic performance. Magnetic properties of nickel ferrite reduces the agglomeration of material and increases the recyclability. The NiFe2O4/ZnO nanocomposites also exhibited better antibacterial activity for Pseudomonas aeruginosa and Staphylococcus aureus, which shows that they can be used for both environmental and biological applications.

In this work, fabrication of Gd3+ substituted nickel spinel ferrite (NiGdxFe2-xO4) nanoparticles was carried out via co-precipitation route. X-ray powder diffraction (XRD) confirmed the spinel cubic structure of NiGdxFe2-xO4 nanoparticles. XRD data also facilitated to determine the divalent and trivalent metal cations distribution at both A and B sites of the ferrite lattice. Site radii, hopping and bond lengths were also calculated from XRD data. The spectral studies elucidated the formation of cubic spinel ferrite structure as well as stretching vibrations of M–O (metal–oxygen) bond at A and B sites of ferrites, represented by two major bands υ1 and υ2 respectively. FESEM analysis confirmed the irregular morphology of NiGdxFe2-xO4 nanoparticles. EDX spectrographs estimated the elemental compositions. The dielectric attributes were explained on the basis of the Debye-relaxation theory and Koop’s phenomenological model. At higher applied frequencies (AC) no prominent dielectric loss was observed. Magnetic parameter variations can be attributed to the substitution of the rare earth cations having larger ionic radii as compared to the radii of Fe3+ ions. Moreover, spin canting, magneto-crystalline anisotropy and exchange energy of electrons also helped in magnetic evaluation. Due to small coercivity values NiGdxFe2-xO4 nanoparticles can be employed significantly in high-frequency data storage devices.

The investigation of effective synthesis routes and applications of magnetic nanomaterials are of great importance in recent years. Here in this article, W3+ substituted manganese ferrite (MnFe2−xWxO4) nano particles were prepared via cost effective and a new micro emulsion strategy. The synthesized materials were first characterized by different physicochemical analyzing techniques to study the structural, spectral and magnetic properties in detail. From the XRD investigation, a cubic phase was observed in all samples of Tungsten substituted Manganese ferrites with a very minute secondary phase. Variation in lattice parameters and observed peak shifting in substituted samples directed towards introduction of tungsten ions in the spinel MnFe2O4. The change in band positions (ν1 and ν2) also suggested the incorporation of foreign impurity (W3+) in spinel lattice. From the magnetic measurement investigation, a significant rise in saturation magnetization (Ms) and coercivity (Hc) was observed. In this regard, the excellent properties and the soft magnetic behavior and of this new tungsten substituted manganese ferrite (MnFe2−xWxO4) suggested its effective utilization in sensors, switching, multilayer chip inductor and many advance technological applications.

Polycrystalline oxide YxMnFe2−xO4 was prepared via low-cost micro emulsion method. As concentration of yttrium ions increased, their electrical and magnetic properties were changed. Effect of secondary phase YFeO3 on the electrical and magnetic properties of the material were also studied and discussed in detail. As concentration of impurity ions increased, variation in resistivity was observed. This variation also affected the magnetic behavior of the prepared Mn-based spinel ferrites. Various parameters such as the saturation magnetization (Ms), retentivety (Mr), coercivity (Hc), anisotropic constant (k1), magnetic moments (μB) have been calculated from recorded M-H loops of all unsubstituted and substituted MnFe2O4 nanoparticles. Ms and Mr values found in the range 27–50 emu/g and 1.8–7.6 emu/g respectively.

La ^3+ ions substituted manganese ferrite (MnFe _2- _x La _x O _4 ) nanoparticles via reverse micelles strategy were synthesized and their structural and electrical properties are discussed in this article. Using low-cost precursors, mono-dispersed, and well crystalline MnFe _2- _x La _x O _4 nanoparticles were prepared at low temperature. X-ray diffraction (XRD) explored cubic spinel structure with minute secondary phase as LaFeO _3 . The crystallite size of MnFe _2- _x La _x O _4 was found to increase from 12.82 nm to 15.95 nm with increased La ^3+ ions contents. The room temperature Fourier transform infrared (FTIR) spectra were recorded in the wavenumber range 1000–400 cm ^−1 that showed the vibrational bands of octahedral and tetrahedral complexes. These bands are the fingerprints of spinel ferrites. Surface morphology characterized by field emission scanning electron microscopy (FESEM) revealed the relative spherical morphology of prepared spinel ferrite particles. The elemental composition analysis from Energy-dispersive x-ray (EDX) spectroscopy confirmed the presence of expected elements in the samples. The modification in resistivity and the enhancement in the dielectric parameters suggested the possible utilization of these soft ferrite nanoparticles in advanced electronics, especially the devices that are required to operate at high frequencies.

MnO _2 nanomaterials were synthesized using a simple wet redox method. Crystal structure of as prepared pure and Al doped MnO _2 nanomaterials was investigated using X-ray diffraction (XRD) technique. Crystal structure was further confirmed by FTIR analysis. Morphology of pure MnO _2 , Al doped MnO _2 , MnO _2 /CNT hybrid structure and Al doped MnO _2 /CNT hybrid structure was studied using scanning electron microscopy (SEM). Energy dispersive X-ray spectroscopy confirmed the presence of all the constituent atoms in the crystal structure of all the samples. Bandgap value was found to decrease with the modification (doping and hybrid structure). Photocatalytic efficiency of all the MnO _2 samples was studied using the photodegradation of methylene blue (MB) under the visible light (solar radiation). Effect of different intermediates on the photodegradation efficiency was studied using different scavengers.

In this present study, a wet chemical method with environmentally friendly and cost-effective bagasse ash is used to prepare the mesoporous silica structures. Significant amounts of silica (SiO _2 ) (∼75 percent) were measured in the bagasse ash as confirmed by x-ray fluorescence spectroscopy (XRF). The porous silica particles with uniform morphology showed a weight loss of ∼150 to ∼45%. The removal of crystal violet was performed with silica extracted from bagasse ash along with two other silica samples prepared from commercially available sodium silicate and TEOS for comparison purposes. The equilibrium adsorption data followed the Langmuir model for both linear and non-linear adsorption isotherm. The maximum monolayer capacity was found to be 26.53 mg/g. From the Langmuir isotherm, the value of ∆H is (SiO _2 (SS) = 0.83, SiO _2 (BA) = 5.19, and SiO _2 (TEOS) = 3.05), which indicates that the uptake of CV dye on mesoporous silica particles could be attributed to physical adsorption. The positive value of ∆H confirms that the adsorption is endothermic, and the positive value of ∆S indicates a certain structural modification and randomness increases in solid/liquid interface. The respective activation energy values for CV dye adsorption on mesoporous SiO _2 (SS), SiO _2 (BA), and SiO _2 (TEOS) are 0.83, 5.19, and 3.05 kJ mol ^−1 . All values are less than 8, showing that it is corresponding to physical adsorption. The findings further show that silica obtained from the bagasse ash is a cost-effective and equally effective adsorbent for the removal of crystal violet from an aqueous solution.