Adsorption Capacity For Rhodamine Research Articles

Efficient removal of Rhodamine B dye using biochar as an adsorbent: Study the performance, kinetics, thermodynamics, adsorption isotherms and its reusability

Removal of toxic dyes such as Rhodamine B is essential as it pollutes aqueous and soil streams as well. This comprehensive study explores the potential of Calophyllum inophyllum seed char as an efficient bio-adsorbent based on their characteristic properties and a comparative study between various carbon-based adsorbents on the adsorption capacity of Rhodamine B dye. In this study, the char was prepared from Calophyllum inophyllum seed using a slow pyrolysis process (298 K/min) at an optimum temperature of 823 K and used as an adsorbent for the removal of Rhodamine B from water. The resulting char was mesoporous and had 155.389 m2/g surface areas (BET) and 0.628 cc/g pore volume. The formation of pores was observed from the SEM analysis. The adsorption studies were tested and optimized through various parameters such as solution pH, adsorbent dosage, initial dye concentration, stirring speed, contact time, and solution temperature. Maximum 95.5 % removal of Rhodamine B was possible at the pH: 2, stirring speed: 100 rpm, time: 25 min, temperature 308 K, and dose: 1.2 g/L. The highest adsorption capacity at equilibrium was determined to be 169.5 (mg/g) through Langmuir adsorption isotherm studies and followed pseudo 2nd order kinetics. The thermodynamics study confirmed the adsorption processes were spontaneous (ΔG°=−0.735 kJ/mol) and endothermic (ΔH° = 4.1 kJ/mol) processes. The reusability study confirmed that the mesoporous char can be reused as an efficient adsorbent for up to 3 cycles for environmental remediation.

Rapid removal of Rhodamine B by phosphoric acid-modified activated carbon derived from rape straw

ABSTRACT A series of activated carbon was obtained from rape straw by chemical modification with phosphoric acid (H3PO4). The activated carbon was characterized and the adsorption capacity for Rhodamine B (RhB) from water was analysed. The SEM images showed that PRC-40 is a porous material and the BET analysis revealed a high surface area of 1720 m2/g with the coexistence of micropores and mesopores. The FTIR spectra determined the presence of oxygenated functional groups at its surface. The XPS spectra revealed that the content of carboxyl and metaphosphate groups in the modified activated carbon significantly increased, and this is conducive to the adsorption reaction. The XRD pattern showed the amorphous nature of carbon. The effect of significant parameters, such as the concentration of H3PO4 for modification and pH value, has been discussed. The kinetic data showed that the pseudo-second-order model is predominant. Besides, the Langmuir model was compatible well with the equilibrium data, and the maximum adsorption capacity of the activated carbon modified by H3PO4 was 2882.84 mg/g. Therefore, agricultural waste and rape straw can be used to prepare effective adsorbents for the application with the removal of dye from wastewater.

The valorization of rosemary waste as a new biosorbent to eliminate the rhodamine B dye

The widespread use of dyes is one of the leading causes of water contamination. Activated carbon is a common adsorbent used in water treatment by one of the most efficient physicochemical techniques: adsorption. As an agricultural waste, the conversion of unwanted rosemary biomass (stems and roots) into activated carbon material (RS-AC) was investigated using varied phosphoric acid activation ratios at 400 °C. Rhodamine B was utilized as a model dye in water in this work to understand better dye depolluting by RS-AC. Many standard methods were used to characterize the materials, including XRD, FTIR, Boehm titration, SEM/EDX, and pHzpc. The effects of RS-AC dosage, adsorption temperature, adsorption duration, and solution pH on the adsorption of Rhodamine B by RS-AC were studied better to understand the process's kinetic and thermodynamic characteristics. The thermodynamic study revealed that the adsorption process is endothermic, the pseudo-second-order kinetic model adequately explains the experimental data, and the equilibrium data showed an excellent fit to the Langmuir isothermal model for a maximum monolayer's adsorption capacity of Rhodamine B (Qmax = 65.78 mg/g). The density of function theory (DFT) was employed with the B3LYP/6-311G(d,p) base to get an idea for the activated sites on Rhodamine B and to explain the process of adsorption; eventually, the results agree with the experimental results.

Transformasi Abu Vulkanik dan Limbah Seng menjadi Nanokomposit ZnO-SiO2 dan Aplikasinya untuk Degradasi Rhodamin B

Rhodamine B is a non-biodegradable organic pollutant that is difficult to decompose by microorganisms. If it is possible to be degraded it will take a long time. The semiconductor used is ZnO using SiO2 host material. The reason for using SiO2 is that apart from high efficiency, there are also abundant raw materials because the eruption of Mount Merapi occurs regularly every 4 years. The high content of SiO2 in volcanic ash can be utilized and processed into silica gel through the formation of potassium silicate resulting from the reaction between SiO2 in volcanic ash and potassium hydroxide. In addition to the presence of abundant SiO2, ZnO sources from lathe workshop waste are also easily obtained. The manufacture of ZnO/SiO2 nanocomposites was carried out using the sol – gel method because it is easy and has high effectiveness. ZnO/SiO2 nanocomposite was applied as an adsorbent to degrade Rhodamine B. This study aims to determine the character of ZnO/SiO2 nanocomposite and to determine the best conditions for optimal degradation. Synthesis of ZnO/SiO2 nanocomposite based on volcanic ash and zinc waste resulted in a composite size with a size range of 100-200 nm and a uniform circular shape. The results of the FTIR test show that SiO is at a wavelength of 993.34 and 1109.07 cm-1, while ZnO is at a wavelength of 443.63 cm-1. The XRD results of ZnO/SiO2 nanocomposite are known to peak at 2𝜃, namely 30.42o, 31.56o, and 44.40o. The application of dye degradation on UV irradiation, as well as looking for pH, time, and concentration gave the maximum Rhodamine B degradation value. The results of this study indicate that the highest efficiency in decreasing the concentration of Rhodamine B was obtained at pH 3 with a contact time of 60 minutes and a concentration of Rhodamine B of 10 ppm. The degradation efficiency of Rhodamine B obtained under these conditions is 95.8690%. Based on the concentration variation data processing using the Langmuir isotherm equation, it is known that the adsorption capacity of Rhodamine B is 97.3458521%.

Adsorption of Rhodamine B from Simulated Waste Water onto Kaolin-Bentonite Composites.

Organic dye rhodamine B is one of the common organic pollutants in the water and soil environment. This study investigated the feasibility of removing rhodamine B from an aqueous solution through adsorption by kaolin, kaolin-sodium bentonite, and kaolin-organic bentonite. Batch adsorption test results showed that the maximum adsorption quantities of kaolin, kaolin-sodium bentonite, and kaolin-organic bentonite were 7.76 mg/g, 11.26 mg/g, and 12.68 mg/g, respectively, implying that the addition of bentonite to kaolin can effectively improve its adsorption capacity for rhodamine B. Moreover, the Langmuir isotherm model is suitable to describe the adsorption of rhodamine B by kaolin and kaolin-sodium bentonite, while it is preferable to use the Freundlich isotherm model in the case of kaolin-organic bentonite. The adsorption kinetic characteristics of rhodamine B, by these three adsorbents, are suitable to be described with a pseudo-second order kinetic model. Furthermore, the characteristics of the above three adsorbents were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The above results indicated that kaolin and organic bentonite can be used to design efficient adsorbents for organic pollutants similar to rhodamine B.

C@TiO2 core-shell adsorbents for efficient rhodamine B adsorption from aqueous solution

Abstract In the present work, C@TiO2 core-shell adsorbents were successfully prepared and the adsorption capacities for rhodamine B (RB) were investigated at different conditions. The adsorbents were prepared by first in-situ hydrolysis and deposition of TBOT on the surface of ZIF-8 nanoparticles to obtain ZIF-8@titania gel, and then carbonization. XRD, SEM, TEM, and N2 adsorption-desorption techniques were employed to characterize the adsorbents. The results showed that the adsorbents were comprised of TiO2 shell and carbon core. Large surface area and hierarchical pores, which were different from ZIF-8 derived porous carbon, were generated due to the less contraction of carbon during carbonization when robust TiO2 shell covered on the surface. The highest adsorption capacity for RB was 298 mg/g on C@TiO2. Apart from the hierarchical pores and large surface area, the low surface charge of C@TiO2 core-shell adsorbents was also observed, which also contributed to the high adsorption capacity for cationic dyes. The reuse experiments showed that the adsorbents maintained the high adsorption capacity after 5 cycles. The high stability is crucial for practical application.

Synthesis of large pore sized mesoporous carbon using alumina-templated strategy for high-performance RhB removal

Abstract The mesoporous carbon dye adsorption materials were synthesized through a simple alumina-templated strategy. The morphology and structure were characterized by Xray diffraction, transmission electron microscopy, nitrogen adsorption–desorption and adsorption capacities of rhodamine B (RhB) were also tested. The results showed that the mesoporous carbon materials exhibit large BET surface area (1093.1 m2·g−1), large pore volume (3.03 cm3·g−1) and large pore size (21.9 nm) due to the consistence pore structure of carbon material and the template nanosheet γ -alumina. Therefore, the mesoporous carbon had high equilibrium adsorption amounts (374.3 mg·g−1) and fast adsorption rate of RhB (317.8 mg·g−1 at 5 min). We also explore the kinetic studies of carbon materials for RhB adsorption, indicating that the kinetics module fit the pseudo-second-order kinetic model and Langmuir model for isothermal adsorption theory. This study promotes a high efficient material for RhB dye adsorption and a promising candidate for toxic dye wastewater treatments.

A Facile Preparation of Ambient Pressure–Dried Hydrophilic Silica Aerogels and Their Application in Aqueous Dye Removal

Highly porous hydrophilic silica aerogels (SAs) are potential excellent adsorbents in aqueous media, which are generally synthesized via a standard sol–gel method followed by the relatively complex and dangerous supercritical fluid drying process. Herein, a facile and novel synthetic method applying ambient pressure drying technology for the rapid preparation of hydrophilic SAs is reported, which are soaked by metal cations without the need of traditional surface modification and supercritical fluid drying process. Chemical and physical properties of the hydrophilic SAs were characterized and compared with a trimethylchlorosilane (TMCS) modified hydrophobic silica aerogel. Besides the integrity and low shrinkage of the as-prepared products, Fourier transform infrared (FTIR) spectra and integrated thermal analyzer (ITA) results revealed the presence of hydroxyl groups as well as the absence of multitudinous hydrophobic groups on the silica surface after soaking. Field emission scanning electron microscope (FE-SEM) and Brunauer–Emmett–Teller (BET) measurements confirmed the mesopores inside the aerogel skeleton. Among the tested metal cations, the Mg2+ soaked SAs demonstrated the best pore properties (pore diameter 9.35 nm and pore volume 1.09 cc/g) while the Fe3+ soaked ones got the biggest surface area (855.62 m2/g) in contrast to other metal cations. Rhodamine B and Methylene blue solutions are used to check the absorption ability of the SAs in aqueous media, where the best adsorption capacity for Rhodamine B and Methylene blue reached 2.8 mg/g and 40.4 mg/g, respectively, showing a potential application in aqueous pollutant removal.

Equilibrium and kinetic modelling of adsorption of Rhodamine B on MoS2

The recent emergence of layered MoS2, which is an earth-abundant material, has gained increasing attention in various fields. In this work, MoS2 is fabricated via a simple hydrothermal method with different sulfur precursors. The effect of S source on the morphologies and adsorption capacities of Rhodamine B (RhB) onto MoS2 were investigated. The results indicated that the MoS2 prepared by CH4N2S exhibited the highest adsorption capacity. The N2 sorption isotherm indicated that the as-prepared MoS2-CH4N2S is a mesoporous microsphere. In addition, the adsorption process can be well described by the Langmuir isotherm model and the pseudo second-order model. The intra-particle diffusion model was also employed to analyze the adsorption mechanisms, which demonstrated that the intra-particle diffusion within the mesopores played an important role in the overall adsorption process. Based on these results, MoS2-CH4N2S obtained in this work can be served as a promising candidate for dye removal in wastewater.

Dye adsorption in ZIF-8: The importance of external surface area

Two kinds of ZIF-8 crystals have been prepared from the ultrasound-assisted hydrothermal reaction of a stoichiometric metal-ligand precursor solution. The addition of surfactant promoted the formation of nanocrystals having a much larger external surface area compared to the non-promoted one. The two samples were then employed to examine the effects of particle size on dye adsorption. The adsorption capacity of Rhodamine B (RB) and methyl orange (MO) was found directly proportional to the external surface area of the ZIF-8 particles, while that of methylene blue (MB) did not vanish with decreasing external area. The residue adsorption is the most clear-cut evidence confirming the penetration of the MB molecule into the ZIF-8 framework, but not the similarly sized MO molecule. The larger RB molecule was also excluded from the internal pores and cover only the external surface of the crystals. Our calculations suggested that each RB and MO molecule occupied 4.7 and 7.9 nm2 of the external surface, respectively. In contrast, MB adsorption occurs both inside the ZIF-8 structure, at a loading of 0.11 molecule per unit cell, and on the external surface with 2.3 nm2/molecule.

Comparison Study on the Adsorption Capacity of Rhodamine B, Congo Red, and Orange II on Fe-MOFs.

Using a microwave-assisted ball-milling approach, Fe-based metal-organic frameworks (Fe-MOFs) were prepared from FeSO4·7H2O and trimesic acid. Scanning electron microscopy, Fourier-transform infrared spectrometry, X-ray, and thermogravimetric analysis were utilized to characterize the thermal stability and structure of the prepared Fe-MOFs. These Fe-MOFs were used to remove organic dyes from aqueous solutions. Specifically, they removed 96.97% of 23.3592 mg/L of Congo red in a 200 mL solution within 300 min of treatment with natural light at 15 °C. Likewise, 88.21 and 70.90% of 22.7527 mg/L of Orange II and 17.8326 mg/L of Rhodamine B, respectively, were removed from 200 mL solutions within 300 min of treatment at 15 °C. At 35 °C, 99.57, 95.98, and 99.38% of 23.3855 mg/L of Congo Red, 22.7365 mg/L of Orange II, and 17.9973 mg/L of Rhodamine B, respectively, were removed from 200 mL solutions within 300 min of treatment. The adsorption kinetics were investigated and the pseudo-first-order kinetic model was found to be superior to the pseudo-second-order kinetic model. Overall, using metal-organic frameworks to treat dye wastewater was found to be inexpensive, feasible, and efficient. Therefore, this material has future prospects in research and applications in the purification of wastewater.

Trichloroacetic acid-modulated synthesis of polyoxometalate@UiO-66 for selective adsorption of cationic dyes

In this study, POM@UiO-66 nanoparticles were fabricated by encapsulation of POM (K6P2W18O62 polyoxometalate) into mesoporous UiO-66 metal organic framework through a solvothermal method with trichloroacetic acid as a modulator to promote the defects formation of UiO-66. The as-prepared samples were characterized by TEM, SEM, PXRD, TG, XPS, and EDX elemental mapping, and the successful combination of POM and UiO-66 was confirmed. Two cationic dyes, rhodamine B and malachite green, and one anionic dye orange G were employed to investigate the adsorption performance of POM@UiO-66. The adsorption data showed that the removal process of cationic dyes by POM@UiO-66 matched well with the pseudo-second-order model and Langmuir isothermal model. The resulting POM@UiO-66 nanoparticles exhibited high adsorption to cationic dyes but low adsorption to anionic dyes, and the adsorption capacities of rhodamine B, malachite green, and anionic dye orange G were 222.6, 190.6 and 40 mg g−1, respectively. Furthermore, the cationic dyes could be selectively removed from a cationic-anionic dye binary system. These results suggested that the novel polyoxometalate-based UiO-66 material is a promising candidate for the adsorption of cationic dyes from effluent.

Study on adsorption of rhodamine B onto Beta zeolites by tuning SiO2/Al2O3 ratio

The exploration of the relationship between zeolite composition and adsorption performance favored to facilitate its better application in removal of the hazardous substances from water. The adsorption capacity of rhodamine B (RB) onto Beta zeolite from aqueous solution was reported. The relationship between SiO2/Al2O3 ratio and adsorption capacity of Beta zeolite for RB was explored. The structure and physical properties of Beta zeolites with various SiO2/Al2O3 ratios were determined by XRD, FTIR, TEM, BET, UV–vis and so on characterizations. The adsorption behavior of rhodamine B onto Beta zeolite matched to Langmuir adsorption isotherm and more suitable description for the adsorption kinetics was a pseudo-second-order reaction model. The maximum adsorption capacity of the as-prepared Beta zeolite with SiO2/Al2O3 = 18.4 was up to 27.97mg/g.

Functional tissues based on graphene oxide: facile preparation and dye adsorption properties

Dye pollution, one of the most serious pollutions in water, remains a challenging issue in environmental engineering. Many strategies including membrane separation, chemical oxidation, electrolysis, adsorption, etc., have been adopted to remove the dyes from water. Compared with other methods, adsorption has its own unique advantages such as low cost, low energy consumption and high efficiency. However, commercial adsorbents have low adsorption capacities and separation of absorbents/water, which hinders their practical applications. In this paper, functional tissues based on graphene oxide are fabricated through a simple immersion method. The structure, morphology and adsorption ability for each of these functional tissues are characterized and analyzed by scanning electron microscopy, Raman spectroscopy, thermal gravity analysis and UV-Vis spectrophotometer. The combination of commercial tissue and graphene oxide can solve the aforementioned problems such as low adsorption capacity, hard separation of adsorbent from water. on the one hand, abundant oxygen-containing functional groups and defects existing in graphene oxide sheets can be used as active adsorption sites, which endows the functional tissue with high adsorption capacity; On the other hand, the crosslinking of commercial tissue and graphene oxide through hydrogen bonding enables the functional tissue to be completely recycled from water after adsorption, which can avoid the secondary pollution caused by adsorbents such as pure graphene oxide. Batch tests are conducted to investigate the adsorption performance, e.g. the influences of adsorption time, initial concentration of dyes, adsorbent amount, and temperature on the adsorption performance. The results suggest that functional tissue has excellent performance for the removal of methylene blue and rhodamine B. Giving that the initial concentrations of methylene blue and rhodamine B are 40 mgL-1 and 30 mgL-1 respectively, the adsorption capacities are 54.84 mgg-1 and 21.74 mgg-1, respectively. It is noteworthy that graphene oxide sheets play a critical role in adsorbing the dyes. The adsorption capacity of functional tissue based on graphene oxide for rhodamine B totally results from graphene oxide component. Calculating the graphene oxide loading on the tissue, the adsorption capacity for rhodamine B reaches 183 mgg-1 at initial concentration of 30 mgL-1. Meanwhile, the adsorbance quantities of the functional tissue for the two dyes increase with adsorption time, initial concentration, adsorbent dosage, and temperature. Kinetic analysis reveals that the adsorption processes for methylene blue and rhodamine B are well-matched with the pseudo-second-order kinetic model, indicating the dominance of chemical adsorption in the whole adsorption process. The thermodynamic parameters indicate that the adsorption is spontaneous and endothermic in nature. In summary, a facile, inexpensive, and eco-friendly synthesis method is developed to fabricate the functional tissues based on graphene oxide. The functional tissues have high adsorption capacities for dyes. The combination of commercial tissue and graphene oxide could be explored as a new adsorbent for removing toxic organic dye pollutants from aqueous environment.

Enhanced photocatalytic activity of a TiO2/graphene composite by improving the reduction degree of graphene

Two kinds of graphene prepared by a high-temperature exfoliation and a solvothermal method were used as supports of a TiO2 catalyst (P25) from Degussa, Inc to prepare TiO2/graphene composites. The photocatalytic activities of the composites were evaluated by their degradation of Rhodamine B in aqueous solutions under visible light. Results indicate that the composites prepared by high-temperature exfoliation have much higher photocatalytic activities than those produced by the solvothermal method or the unsupported P25. Both the adsorption capacity of Rhodamine B on the composites and their light absorption characteristics are independent of the kind of graphene used. The activity increases with exfoliation temperature and reduction degree of the graphene regardless of the methods and conditions used, indicating that a high degree of reduction of graphene can inhibit the recombination of electron-hole pairs generated by light irradiation by increasing electron transfer from TiO2 to the graphene layer.

Preparation of silica aerogels using CTAB/SDS as template and their efficient adsorption

Silica aerogels have been successfully synthesized using cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) as template. This study provides a novel approach to synthesize silica aerogels. The molar ratio of surfactant mixture was CTAB/SDS=1.00. The obtained silica aerogels exhibit very low apparent density (0.044gcm−3) and high specific surface area (856m2g−1). Surfactant packing parameter theory is used to explain the possible formation mechanism of the silica aerogels using mixed surfactant template. In addition, the adsorption capacity of Rhodamine B on the as-synthesized silica aerogels is as higher as that on the commercial silica aerogels.

Regeneration of Rhodamine B Loaded Modified Biosorbent by a Self-Cleaning Eluent: TiO2 Hydrosol

Waste beer yeast was modified by pyromellitic dianhydride to improve its adsorption capacity for rhodamine B (RhB). Results showed that the adsorption capacity of the modified biomass for RhB was 600 mg g ―1 , which was about five times than that obtained on the unmodified biomass. Dye loaded modified biomass was regenerated by (1) a common eluent: HN0 3 solution and (2) a self-cleaning eluent: TiO 2 hydrosol, while the pH of both systems varied from 1 to 4. Desorption experimental results showed that low desorption rates were obtained in both systems after the first desorption cycle. A large volume of HN0 3 solution was needed to obtain high desorption rate, and a concentrated solution of RhB was left, which brought a secondary pollution. As a self-cleaning eluent, acid TiO 2 hydrosol acted both as eluent and photocatalyst. The desorbed RhB could be photodegraded under sunlight irradiation and the same hydrosol could be used in the next desorption cycle without losing its activity, which could economize large volumes of solvent. The results showed an adsorption capacity of the regenerated biosorbent for RhB of 450 mg g ―1 by using hydrosol with pH 2 as eluent after four desorption/photodegradation cycles.

Dye adsorption on unburned carbon: Kinetics and equilibrium

Unburned carbon in fly ash is an important by-product from coal combustion. In this investigation, unburned carbon has been separated from fly ash and been employed as a low cost adsorbent for a basic dye adsorption (Rhodamine B) in aqueous solution. Adsorption isotherm and kinetics of adsorption have been investigated using batch experiments. It is found that dye adsorption capacity depends on initial concentration, pH of solution, and temperature. The adsorption isotherm can be described by Langmuir model and the adsorption capacity of Rhodamine B at 30, 40, and 50 °C can reach 9.7 × 10 −5, 1.14 × 10 −4, and 1.5 × 10 −4 mol g −1, respectively. The pseudo first- and second-order kinetic models have been employed to fit the dynamic adsorption. It is found that the dynamic adsorption follows the pseudo second-order model. Thermodynamic calculations indicate that the adsorption is endothermic reaction with Δ H° at 25 kJ mol −1.