Effect Of Initial Dye Concentration Research Articles

Sulfamic acid incorporated HKUST-1: a highly active catalyst and efficient adsorbent.

Herein we introduce an effective approach for incorporating sulfamic acid (SA) into HKUST-1. The synthesized materials have been characterized using XRD, XPS, BET, FT-IR, SEM, EDX and TEM. The X-ray diffraction pattern of SA@HKUST-1 is analogous to that of parent HKUST-1 in line shape and d-spacing, proving that chemical modification could be obtained without damage to structural solidity. The XPS spectra confirmed successful sulfonation, due to the single S 2p peak being attributable to SO3H groups at 168 eV. Catalytic efficiency was studied for 7-hydroxy-4-methyl coumarin and 3,4-dihydropyrimidinone synthesis and it was found to be highly dependent on the amount of SA loaded over HKUST-1. Moreover, the adsorptive removal activity of some common organic and inorganic pollutants from water has been studied. To fully understand the adsorption process, the effects of initial dye concentration, pH of solution, adsorbent dosage, contact time and temperature on the adsorption process were successfully studied. Under the optimum conditions 10 wt% SA@HKUST-1 was able to reach the maximum adsorption capacity for Pb2+ (298 mg g−1) and Malachite green (290 mg g−1). Hopefully, this will facilitate research on improving the prospective use of MOFs for future applications.

Removal of Methylene Blue from Aqueous Solution by Using Electrical Arc Furnace (EAF) Slag

In recent years, environmental protection has gained a major concern. In line with the rapid growth of various industries, high amount of effluent has been generated and discharged to the environment. One of the concerns is the presence of synthetic dye in the wastewater stream, as it may endanger human and aquatic life. In this experiment, the Electrical Arc Furnace (EAF) slag has been used as an adsorbent to remove methylene blue from the aqueous solution. Batch experiments have been conducted, and the effects of initial dye concentration, pH, adsorbent dosage and temperature were studied respectively. Chemical treatment has been performed to modify the adsorbent. The results reveal that treated EAF Slag has higher efficiency in removing methylene blue compared to raw EAF slag. More pores have been exposed, and impurities on the adsorbent’s surface have been removed, to enhance better removal efficiency. The maximum adsorption capacity for treated EAF is 14.2029 mg/g and for raw EAF Slag is 9.615 mg/g. The maximum removal percentage for treated EAF Slag is 71.01%, whereas raw EAF shows 37.19% removal at pH 10. Both raw EAF Slag and treated EAF slag fits the data for the Langmuir isotherm model which obeys the monolayer adsorption process.

Plant-mediated synthesis of Cu0.5Zn0.5Fe2O4 nanoparticles using Minidium leavigatum and their applications as an adsorbent for removal of reactive blue 222 dye

Cu0.5Zn0.5Fe2O4 magnetic nanoparticles were synthesized using Minidium leavigatum extract and required metal salts by a green method. This method has some benefits such as nontoxic, economic viability, ease to scale up, less time consuming and environmental friendly approach for the synthesis of Cu0.5Zn0.5Fe2O4 magnetic nanoparticles without using any hazardous organic chemicals. The sample was characterized by powder x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX), and Brunauer–Emmett–Teller (BET) surface area analysis. The environmentally friendly synthesized nanoparticles were used as adsorbent for removal of reactive blue 222 (RB 222) dye from aqueous solutions. The effects of initial dye concentration and nanoparticle dosage on dye adsorption were assessed. Adsorption equilibrium studies were investigated to determine the adsorption capacity of the adsorbents by using the Langmuir and Freundlich isotherm models. The Langmuir model yielded more suitable than the Freundlich model for the adsorption of RB 222 on Cu0.5Zn0.5Fe2O4 magnetic nanoparticles. Adsorption kinetics obeyed a pseudo second-order kinetic model.

Efficient and highly selective adsorption of cationic dyes and removal of ciprofloxacin antibiotic by surface modified nickel sulfide nanomaterials: Kinetics, isotherm and adsorption mechanism

In the present work, the nickel sulfide nanomaterial with the negative surface charge was synthesized by a simple and eco-friendly route using nickel acetate, thioacetamide and l-glutathione reduced (GSH). The new surface-modified nanomaterial was systematically characterized using various techniques such as XRD, FE-SEM, TEM, EDX, XPS, TGA, Zeta-potential, and FT-IR, and then applied for the removal of dyes and antibiotics. The nanomaterial exhibited selective adsorption towards cationic dyes: methylene blue (MB) and crystal violet (CV) with a high adsorption capacity of 1006.52 mg g−1 and 1946.61 mg g−1, respectively. The adsorption capacity for the removal of ciprofloxacin antibiotic (CIP) was 971.83 mg g−1 which is extremely high. The selectivity of MB in binary mixtures was investigated using two anionic dyes: methyl orange (MO) and orange G (OG). The separation efficiency (α) for MB in MB/MO and MB/OG mixtures was 97.75 % and 99.16 %, respectively. The adsorption process for all the adsorbates followed pseudo-second-order kinetics and the Freundlich isotherm model. The mechanism of interaction was analyzed through pH effect, zeta-potential measurement, FT-IR and XPS analysis, implying that the electrostatic interaction is mainly involved in the adsorption. In addition, the parameters like the effect of initial dye concentration and temperature on the adsorption process were studied. The adsorbent is reusable up to 4 times with 97 % efficiency. Thus, the prepared GSH-capped nanomaterial is an effective adsorbent for the removal of antibiotics and the selective removal of cationic dyes with high adsorption capacity.

P hotocatalytic A ctivity of Modified TiO 2 for M ethyl O range R emoval

In this study, the researcher review on the modified TiO2 preparation via wet impregnation method for dye removal application. The bare TiO2 and Ag-TiO2 that have been synthesized undergo characterizations using XRD, FESEM-EDX and UV-Vis spectroscopy. The XRD pattern showed that the synthesized TiO2 was of pure anatase phase. The crystal structure of anatase TiO2 was not disturbed upon doping with Ag. FESEM images revealed that the TiO2 constitutes of various sizes of spherical and square-like shapes. EDX mapping illustrates that dopant metals are dispersed in a uniformed manner onto the TiO2 support and appeared as metal oxide. The bare TiO2 that has been modified acts as a photocatalyst to remove MO through the batch method. The effects of initial dye concentrations (5-25 ppm), pH solutions (2–9), catalyst loadings (0.5–4) g/L,) and light sources (visible, solar, UV) were analyzed. It was discovered that photocatalytic experiment performed using Ag-TiO2 has greater efficiency of MO removal that ranges from 32% to 100% in contrast to bare TiO2 with MO removal of 12%-67% for comparable dosages of photocatalyst at initial MO concentration of 5 ppm in both alkaline and acidic conditions under UV irradiation. It was postulated that Ag-TiO2 photocatalyst is the better candidate for effective dye removal.

Kinetics studies on photodegradation of methyl orange in the presence of C-N-codoped TiO2 catalyst

This work investigated the photodegradation of azo dye, methyl orange, without and with the addition of C-N-codoped TiO2 catalyst using a visible halogen-lamp as a light source. C-N-codoped TiO2 was prepared by free-organic solvent peroxo sol-gel method. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of methyl orange were studied. Photodegradation process for methyl orange solution at acidic condition showed high removal percentage. 5 mg L-1 methyl orange achieved color removal until 94% for 180 min irradiation in photodegradation process with the presence of C-N-codoped TiO2 catalyst, and approximately 70% TOC removed as the results of mineralization process. The kinetics reaction rate of photodegradation of methyl orange dye with the addition of C-N-codoped TiO2 followed pseudo-first order represented by Langmuir-Hinshelwood model, the kinetics constant of photodegradation became higher by decreasing the initial concentration of methyl orange. Three organic byproducts of methyl orange formed during photodegradation process was identified by LC-MS/MS system then degradation pathway of methyl orange photodegradation in the presence of C-N-codoped TiO2 catalyst was proposed.

Adsorption removal of methylene blue onto activated carbon/cellulose biocomposite films: Equilibrium and kinetic studies

Activated carbon/cellulose composite (ACC) biosorbent films were fabricated via solution casting by combining 1–3% w/v of activated carbon with the cellulose solution which dissolved by lithium chloride/N, N-dimethylacetamide. Both cellulose solution and activated carbon were prepared from sisal fiber. These films were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscope (FTIR), thermogravimetric analyzer (TGA), and X-ray Diffractometer (XRD). The specific surface area of activated carbon was found to be 1165 m2/g. The maximum methylene blue adsorption capacity of the ACC film reached 103.66 mg/g with the dye concentration of 100 mg/L, solution pH of 6.9, at 35○C for 24 h. The adsorption data suggested that the isotherm model for the equilibrium process was that of Langmuir model, and the adsorption kinetic was best described by pseudo-second-order model. The effect of initial dye concentration (20–100 mg/L), contact time (0–2,880 min), pH (3–11), and temperature (35–80○C) on adsorption capacity of ACC3 film were also examined. Thermodynamics studies of ACC3 film revealed that the adsorption process was endothermic, spontaneous, and feasible. Therefore, the activated carbon/cellulose composite films can be potentially used as biosorbents to remove dyes from contaminated water.

Adsorptive Removal of Remazol Brilliant Violet-5R Dye from Aqueous Solutions using Calcined Eggshell as Biosorbent

As a result of industrial development water pollution has become a major issue. Providing clean water of sufficient quality and quantity is essential. According to literature, 100 000 different dyes are used worldwide in the printing, food and textile industries. Remazol Brilliant Violet-5R belongs to the group of azo dyes used in the textile industry. The purpose of this paper is to study the removal of anionic dye RBV-5R using calcined eggshell. We investigated the effect of initial dye concentration (20-100 mg/L RBV-5R), biomass amount, contact time, temperature, and pH on the adsorption process. We calculated the amounts of adsorbed material in equilibrium and the efficiency of the adsorption process. Various studies were performed on the adsorption process and the adsorbent morphology (EDX, SEM, FTIR, Raman), as well as isotherm (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich), kinetic and diffusion models were used to characterize the process. Calcined eggshell was also characterized by thermogravimetric, BET surface methods. Based on the results obtained, it can be said that the calcined eggshell can be used effectively to remove the dye from the aqueous solution.

Color Removal of Azor A Dye in Aqueous Solution by ZnO and Hydrogen Peroxide Under Solar Irradiation

ZnO nanoparticles was synthesized by sol gel process and investigated using XRD, FT-IR, SEM and AFM analysis. Advanced oxidation processes (AOP) have showed to be very effective in degradation of most pollutants in wastewaters. The effect of initial concentration for Azure A dye was studied for five concentrations from (1×10−5 M to 5×10−5 M). The photocatalytic degradation of the dye was observed spectrophotometically. Also, the study involved effect of initial dye concentration, hydrogen peroxide dosage, pH, temperature and photocatalyst dose under solar light. The study involved to find out the optimum operating conditions of the treatment processes. Generally it has been found that the rates of photodegradation of azure A dye was higher in presence of solar radiation and ZnO photocatalyst. Also, photocatalytic ZnO showed the importance with light lead to enhance the generation of hydroxyl radicals which drive the photo oxidation processes. The kinetic and the percentages of degradation were studied at different intervals for 60 min. The experimental results indicated that the maximum photodegradation 89% of Azor A dyes occurred with ZnO photocatalyst at acidic media. COD analysis of The photodegraded samples showed reduction in COD after 60 min.

Biogenic fabrication of ZnO nanoparticles using Trigonella foenum-graecum (Fenugreek) for proficient photocatalytic degradation of methylene blue under UV irradiation

The biosynthesis is an eco-friendly, reliable, sustainable protocol for preparing nanomaterials where use of natural, biodegradable, non-toxic and safe reagents takes place. In the present work, an efficient, facile and eco-friendly approach has been used for the synthesis of zinc oxide nanoparticles (ZnO-NPs) using Trigonella foenum-graecum (Fenugreek) aqueous seed extract as bio-reducing agents and capping agent, thus eradicating the requirement of conventional reducing agents. Different characterization techniques like UV–Vis spectroscopy, UV–Visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy, photoluminescence (PL) study and energy dispersive X-ray were employed for confirmation of optical properties, shape, size, surface structure, crystalline nature and elemental proportions of the biogenic ZnO-NPs. FTIR analysis confirms the active role of bioactive phytochemical constituents present in the Trigonella foenum-graecum aqueous seed extract. XRD analyses of the as prepared ZnO-NPs are crystalline in nature and have no other impurity phase. UV–Vis spectral data suggested optical band gap energy of 2.97 eV for biosynthesized ZnO-NPs showing their small size owing to quantum confinement. UV–Vis spectra of ZnO-NPs show the characteristic absorption band at 364 nm, which can be assigned to the intrinsic band gap absorption of ZnO-NPs because of the electron transitions from the valence band to the conduction band. In addition, the efficacy of biosynthesized ZnO-NPs to act as highly efficient photocatalyst for methylene blue (MB) dye degradation under UV-light under different experimental conditions was confirmed in this study. The effect of initial dye concentration, ZnO photocatalyst dosage and the reusability tests were investigated. Improved photocatalytic behavior was discussed and influence of active species was further investigated using hydroxyl radical (●OH), superoxide anions (●O2−) and hole (h+) scavengers to explain the possible mechanism of the photocatalytic MB dye degradation under UV light irradiation.

Degradation and mineralization of violet-3B dye using C-N-codoped TiO<sub>2</sub> photocatalyst

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO<sub>2</sub> catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO<sub>2</sub> followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L<sup>-1</sup> violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO<sub>2</sub> catalyst, and approximately 44% TOC was removed as a result of the mineralization.

Filter paper supported nZVI for continuous treatment of simulated dyeing wastewater

In this study, polyacrylic acid modified filter paper (FP/PAA) was synthesized by in-situ polymerization of acrylic acid, which was used as a matrix to chelate nano-scale zero valent iron (nZVI). The loading content of nZVI in the filter paper reached 24.8%. The fabricated composite FP/PAA/nZVI was characterized by SEM, FT-IR and TGA respectively. Moreover, it was used for the removal of methyl blue and methylene blue as model anionic and cationic dyes. The effect of initial dye concentration on decolorization efficiency was investigated. The results showed that FP/PAA/nZVI enhanced the removal of dye from the simulated dye wastewater and the decolorization efficiency exceeded 95% for the dye solutions lower than 20 mg/L. More importantly, the filter paper supported nZVI realized the continuous treatment of simulated dye wastewater by a simple filtration process. This study hopes to serve as a basis for the application of nZVI in textile wastewater treatment.

Removal of a reactive dye using NaOH-activated biochar prepared from peanut shell by pyrolysis process

ABSTRACT Firstly, biochar was produced using peanut shell wastes at 500°C under inert gas nitrogen by pyrolysis. Then, the biochar was activated with NaOH. Activated biochar produced was characterized by SEM, FTIR, elemental analysis and N2 adsorption. The activated biochar obtained was utilized as an adsorbent for the removal of remazol orange RGB (RO-RGB), a reactive dye, from aqueous solution by adsorption method. The effects of initial dye concentration (20, 50, 75, 100 and 150 mg L−1), solution temperature (20°C, 30°C, 40°C, and 50°C) and pH (3, 5, 7 and 9) on the adsorption were investigated at different contact times. The amounts of the dye adsorbed increased with increasing initial dye concentration and temperature while it was decreasing with increasing pH. The most percent adsorption was found as 94.49% under conditions studied. Adsorption followed the Langmuir and Freundlich isotherm models as well as the pseudo-second order kinetic model. A favorable adsorption was observed by means of a dimensionless equilibrium factor, an essential characteristic of the Langmuir isotherm. From the results of single-stage batch adsorption, the required biochar mass for 90% dye removal in 10 L dye solution was estimated as 124.61 g. Thermodynamic data indicated a spontaneous and endothermic adsorption.

Adsorption ability of activated carbons from Phoenix dactylifera rachis and Ziziphus jujube stones for the removal of commercial dye and the treatment of dyestuff wastewater

The activated carbons were prepared from Phoenix dactylifera rachis (PRAC) and Ziziphus jujuba stones (JSAC) using chemical activation by H3PO4. Then, they applied to eliminate a commercial reactive dye BEZAKTIV Red S-Max (BRSM). The resultant carbons PRAC and JSAC were characterized by N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM) and Boehm titration method. The BET apparent surface area of the PRAC and JSAC was 1283 and 1896 m2/g, respectively, with predominance acidic character. The effects of initial dye concentration and contact time, pH and temperature on the adsorption were investigated, and it was showed that the elimination percentage decreases as the initial concentration increases, but it rose with the temperature. The experimental equilibrium data were studied using Langmuir, Freundlich and Temkin models, and it was found that the Langmuir model described well the BRSM adsorption (R2 ≥ 0.96), showing a maximum adsorption capacity of BRSM onto PRAC and JSAC of 196.08 and 37.04 mg/g, respectively. The BRSM adsorption kinetic was examined by pseudo-first-order, pseudo-second-order, elovich and intraparticle diffusion models, and it was showed that BRSM adsorption onto used carbons followed pseudo-second-order. The obtained thermodynamic parameters indicated that the phenomenon is spontaneous and endothermic. In addition, the thermal regeneration of the examined carbons revealed that they can be reused on adsorption test. Finally, the results indicated that the Phoenix dactylifera rachis carbon could be considered as low cost material for the elimination of BRSM dye and dyes from dyestuff wastewater (DW).

Removal of Malachite Green Dye from Aqueous Solution by Adsorption Using Modified and Unmodified Local Agriculture Waste

Local agriculture waste (Shell’s seeds of Ziziphus spina christi) (SZC), in both its unmodified SZC and acid-modified (SZC-AC) forms, was investigated for its potential use as a low-cost adsorbent for the removal of malachite green (MG). Characterization of the adsorbents was carried out using scanning electron microscope (SEM), Fourier transforms infra-red spectroscopy (FTIR), pH surface, Boehm titration, including, other physical and chemical properties of adsorbent. The effects of initial dye concentration, contact time, solution of pH, temperature and adsorbent dosage were investigated in detail by batch adsorption experiments. For the adsorption of MG were fitted using Langmuir and Freundlich isotherm models, equilibrium isotherms were applicable with maximum monolayer adsorption capacity wear 48.780 mg/g and 370.370 mg/g for the raw shells seeds of Ziziphus spina christi (SZC) and the activated carbon prepared from shells seeds by sulphuric acid SZC-AC, respectively. Kinetics studies showed that both followed the pseudo-second order. Thermodynamics studies indicated that the adsorption of MG was spontaneous on SZC and SZC-AC, and the reactions were endothermic and exothermic, respectively. The proposed adsorbents were successfully applied to the removal of malachite green dye from different water samples with a recovery % >95% and a relative standard deviation (RSD%) <3%.

REMOVAL OF POLLUTANT TEXTILE DYE FROM AQUEOUS SOLUTION USING MIXED NANOCOMPOSITE OF IRON /ALUMINA OXIDE AND ITS MODIFIED WITH CATIONIC SURFACTANTS

Nanocomposites of mixed iron/aluminum oxide (Fe2O3- Al2O3) were prepared by hydrothermal method and modified with a cationic surfactant CTAB for the removal of dye (C.I Acid Orange 67). The morphology and size of the obtained nanocomposites were characterized by SEM, EDX and TEM. The resulting composite and its modified form have been characterized by using the XRD, FT-IR. Batch adsorption experiments were carried out for the removal of acid dye AO67 from aqueous solution. The adsorption of AO67 over the mixed nanocomposite and its modified form were investigated for different parameters such as the effect of CTAB concentration, effect of pH dye solution, effect of initial dye concentration, mass of the adsorbent and the contact time on the adsorption capacity. The adsorption capacities were evaluated using the Langmuir, Freundlich Dubinin- Radushkevich (D-R) and Temkin adsorption isotherm models, the equilibrium experimental data fits perfectly the Langmuir isotherm. Batch kinetic data were analyzed using pseudo first and second order kinetic models, and otherwise different kinetic models. Kinetic data of adsorption are well fitted by the pseudo 2nd order kinetic model with a good agreement with the intra-particle diffusion model. For this the prepared nanocomposite could be regarded as a potential adsorbent for AO67 removal in a wastewater treatment. and were used the optimum conditions for application in the removal of simulated wastewaters dyes (RB222, RY145 and AR37).

Photocatalytic decolorization of methylene blue using TiO2/UV system enhanced by air sparging

In this work, the photocatalytic degradation of wastewater containing an organic dye (Methylene Blue) was investigated in a slurry-type reactor enhanced by air sparging. Commercial TiO2 was used as the photocatalyst which was activated using ultraviolet irradiation. The effects of initial dye concentration, photocatalyst loading, solution pH and air’s superficial velocity on the degradation efficiency were evaluated. The degradation efficiency of the dye increased with increasing the pH of the solution and decreasing the initial dye concentration. Moreover, increasing the catalyst loading up to 1 g/l showed an improvement in the degradation efficiency. However, the efficiency deteriorated with a further increase in the catalyst loading. Introducing air into the reaction medium in the form of micro-bubbles significantly improved the degradation efficiency by providing oxygen molecules required for the oxidation reaction. Furthermore, these air bubbles created turbulence in the reaction medium, which resulted in the enhancement of the mass transfer rate of dye molecules from the solution bulk to the catalyst surface with a subsequent increase in the degradation efficiency. A complete decolorization of 10 ppm dye solution was achieved in the neutral solution (pH = 7) with a catalyst loading of 1 g/l and an air superficial velocity around 2 cm/s. The effect of the air superficial velocity on the degradation reaction kinetics was investigated and the reaction was found to follow the pseudo second order rate law.

Alginate-Based Hydrogel Beads as a Biocompatible and Efficient Adsorbent for Dye Removal from Aqueous Solutions.

In this study, sodium alginate was employed as a starting material for preparing two kinds of biocompatible adsorbents, including calcium alginate hydrogel beads and magnetic hydrogel beads. Fourier transform infrared spectroscopy, X-ray diffraction pattern, and scanning electron microscopy/energy-dispersive X-ray techniques were used to characterize the prepared adsorbents. The performance of the prepared adsorbents for the removal of methyl violet from aqueous solution was studied in detail. Both kinetics and equilibrium aspects of methyl violet adsorption were investigated, and the obtained equilibrium and kinetics data were described with various adsorption models. The effects of initial dye concentration, adsorbent dosage, and temperature on adsorption performance were investigated. Thermodynamic parameters of adsorption were obtained as well.

Preparation of CoFe2O4@vacancy@mSiO2 core-shell composites for removal of organic pollutant in aqueous solution

CoFe2O4@vacancy@mSiO2 magnetic composites with core-shell structure were prepared with a simple two-step route and used for removal of organic pollutant in aqueous solution. The as-prepared nanocomposites were characterized by Brunner−Emmet−Teller (BET) measurements, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The adsorption performances of CoFe2O4@vacancy@mSiO2 for Rhodamine B (RhB) were evaluated. The effects of initial dye concentration, adsorbent dosage, contact time, solution pH, temperature, ionic strength on dye adsorption were studied. Finally, four consecutive adsorption–desorption cycles were conducted to investigate the reusability of CoFe2O4@vacancy@mSiO2. The results showed that CoFe2O4@vacancy@mSiO2 could remove RhB in a wide pH range. Increasing ionic strength could enhance the adsorption capacity of CoFe2O4@vacancy@mSiO2 for RhB. The adsorption equilibrium obeyed Freundlich isotherm model and the maximum adsorption capacity under optimal conditions could reach 172.34 mg/g. The adsorption process of RhB onto CoFe2O4@vacancy@mSiO2 nanocomposites was very fast and kinetic process could be represented by pseudo-second-order kinetic model. Thermodynamic parameters suggested that the adsorption of RhB onto CoFe2O4@vacancy@mSiO2 was spontaneous and exothermic in nature. Based on the above results, the synthesized CoFe2O4@vacancy@mSiO2 could be used as an effective adsorbent for RhB removal.

Utilization of dye-loaded activated carbon as a potential alternative fuel source: a feasibility study through calorific and thermo-gravimetric analysis.

The disodium salt of Rose Bengal [4, 5, 6, 7-tetrachloro-2', 4', 5', 7'-tetraiodofluorescein] commonly finds application in medical procedures and its removal from aqueous solution is difficult owing to its high molecular weight of 1017.67g/mol. Activated carbon was prepared from Prosopis juliflora and immobilized into sodium alginate beads and doped with aniline for enhanced adsorption of Rose Bengal. The effect of initial dye concentration, beads' dosage, contact time, and the temperature over the adsorption of Rose Bengal dye were studied. The optimum conditions derived for maximum dye uptake capacity were 4mg/L of initial dye concentration, contact time of 60min with the adsorbent dosage of 0.2g, and temperature of 303K at neutral pH. The equilibrium data were found to be best fitted for Langmuir -1 model, whereas the kinetics were interpreted through Ho-Mckay's pseudo-second-order equation. The adsorbents were subjected to thermo-gravimetric studies to determine the activation energy under a heating rate of 20°C/min. The activation energy was computed using Broido's plot and was found to be 35.21 ± 0.84kJ/mol for the activated carbon, and 16.77 ± 2.19kJ/mol for the dye-adsorbed beads. The heat capacity was determined through differential scanning calorimetry and was calculated to be 19.41J/g°C for activated carbon and 39.43J/g°C for beads post-adsorption of Rose Bengal dye.