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Batch adsorption experiments were carried out to study the removal of the toxic Methylene Blue Dye (MBD) from synthetic aqueous solutions using the nanoparticles form of Arthrospira platensis NIOF17/003. The adsorption capacity of the adsorbent for MBD was investigated using different amounts of A. platensis nanoparticles at different contact times, temperatures, pH, and MBD initial concentrations in the synthetic aqueous solution. In addition, A. platensis nanoparticles were characterized using Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), Fourier Transform Infrared (FTIR), and Ultraviolet spectra (UV) techniques. The optimum removal of MBD was found at a concentration of 0.4 g A. platensis nanoparticles. A. platensis nanoparticles remove 93% of MBD in 5 min (under agitation conditions at 150 rpm). The highest adsorption capacity was found by the Langmuir model to be 58.8 mg g−1. It is an endothermic process with spontaneity increasing with temperature. The probable mechanism for the adsorption is chemisorption via surface-active charges in the initial phase, which is followed by physical sorption by occupying pores of A. platensis. MBD adsorption by A. platensis follows pseudo-second-order kinetics. The Freundlich and Langmuir models fit well with the experimental data. The adsorption experiments suggested that the regeneration of the adsorbents was possible for repeated use, especially regarding MBD up to 65.8% after three cycles, which proves it can be easily recycled. In conclusion, the nanoparticles of A. platensis have a significant adsorption potential in the removal of MBD from effluent wastewater. [ABSTRACT FROM AUTHOR]

The dried form of the brown seaweed Sargassum latifolium was tested for its ability to remove toxic Methylene Blue Dye (MBD) ions from aqueous synthetic solutions and industrial wastewater effluents. In a batch adsorption experiment, different initial concentrations of MBD (5, 10, 20, 30, and 40 mg L−1), sorbent dosages (0.025, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 g L−1), contact time (5, 10, 15, 30, 60, 120 min), pH (3, 5, 8, 10, and 12), and temperature (30, 40, 50, 60 °C) were observed. Dried powder of S. latifolium was characterized before and after adsorption of MBD using different techniques, such as FTIR, SEM, UV visible spectral examination, and BET techniques. The BET surface area suggests the formation of S. latifolium was 111.65 m2 g−1, and the average pore size was 2.19 nm. The obtained results showed that at an MBD concentration of 40 mg L−1, the adsorption was rapid in the first 5, 10, and 15 min of contact time, and an equilibrium was reached in about 60 and 120 min for the adsorption. At the optimum temperature of 30 °C and the adsorbent dose of 0.1 g L−1, approximately 94.88% of MBD were removed. To find the best-fit isotherm model, the error function equations are applied to the isotherm model findings. Both Tempkin and Freundlich isotherm models could appropriate the equilibrium data, as well as the pseudo 2nd order kinetics model due to high correlation coefficients (R2). Thermodynamic and Freundlich model parameters were assessed and showed that the mechanism of the sorption process occurs by an endothermic and physical process. According to the results of the experiments, S. latifolium is a promising environmentally friendly approach for eliminating MBD from the aqueous solution that is also cost-effective. This technology could be useful in addressing the rising demand for adsorbents employed in environmental protection processes. [ABSTRACT FROM AUTHOR]

For the first time the feasibility of using an alkaline wastewater coming from the pulp and paper industry as an activator, partially (50 vol%) replacing commercial sodium hydroxide, in the production of cork-based activated carbons was evaluated. The activated carbons showed the highest value of specific surface area ever reported for cork-based activated carbons (1670 m 2 /g), surpassing several other commercial and waste-based ones. These eco-friendly cork and paper waste-based activated carbons were then evaluated as methylene blue adsorbent materials. The influence of contact time, methylene blue initial concentration and adsorbent amount on the methylene blue removal efficiency by the activated carbons was studied. Extremely fast (>99.9% removal in 5 min) and efficient methylene blue adsorption (uptake of 350 mg/g) by the cork and paper waste-based adsorbents was achieved, which demonstrates the huge potential of these innovative adsorbents. These activated carbons were produced using two unexplored industrial by-products (alkaline wastewater and cork) and, therefore, may be an inexpensive source of activated carbons, which can be used for the effective removal of dyes from wastewaters. Furthermore, despite the very large surface area and high removal efficiency this is not a nano material (being around 30–50 μm in size), its capabilities being due to its unique cork-derived microstructure, and hence it can be handled and removed/filtered much more easily than nanocarbons, and without any associated health or environmental risks. [ABSTRACT FROM AUTHOR]

In this research, aluminum-based drinking water treatment sludge is used as a starting material and immobilized by sodium alginate to develop low cost adsorbent for the removal of methylene blue (MB) from aqueous solutions. The studied variables included pH, adsorbent dose, initial MB concentration and contact time. Characteristics of the adsorbent were also studied using scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR). It was revealed from kinetic tests that removal efficiency of MB was 88.5% under the optimum conditions of pH 8, initial MB concentration of 50 mg/L, contact time of 60 min, and adsorbent dose of 0.3 g/L. The oxygen functional groups such as -OH, C-O-C and C=O were found on the surface of developed adsorbent by FTIR. In addition, the adsorption data fitted well the Langmuir adsorption model with the maximum sorption capacity of 909.1 mg/g, and followed the pseudo-second-order kinetics. Findings of this study indicate that the prepared adsorbent is promising for further development of an effective and economical adsorbent material in the near future. [ABSTRACT FROM AUTHOR]

The potential of Lantana camara L. in raw (LR) and modified form (LM) for adsorptive removal of two basic dyes, namely Rhodamine B (RB) and methylene blue (MB), from aqueous solution has been investigated. The adsorbent was characterized by various analytical techniques. The results obtained indicate that adsorption of the dyes strongly depends on pH, initial dye concentration, contact time, and presence of surfactant in batch mode and on flow rate and bed depth in column mode. Kinetic studies revealed that removal of the dyes was governed by pseudo-second-order kinetics and a film diffusion mechanism controls the overall rate of the sorption process. The equilibrium adsorption data were interpreted using various isotherm models, and the data were best fit by the Freundlich isotherm model. Modified adsorbent displayed improved adsorption capacity for RB and MB of 34.24-147.05 mg/g and 23.25-111.12 mg/g, respectively, at 30 °C. Thermodynamic parameters indicated that the dye removal process was spontaneous, endothermic, and chemical in nature. The highest desorption efficiency of spent adsorbent was achieved using sulfuric acid (1 M). The results show that LM has considerable potential for removal of RB and MB from aqueous solution. [ABSTRACT FROM AUTHOR]

Introduction: Textile industry is regarded as one of the largest producers of dye and organic compounds, and Methylene Blue is the most commonly used dye material. In the present study, peanut shell powder was used as a low-cost adsorbent for removal of Methylene blue dye from aqueous solutions. Methods: In this experimental study, effect of operating parameters including pH (2-12), reaction time (5-210 min), adsorbent dosage (0.1-1 g/l) and initial dye concentration (10-120 mg/l) were assessed on dye removal from synthetic wastewater. Moreover, the adsorption behavior of dye was evaluated by Freundlich and Langmuir isotherms. Results: Maximum removal efficiency of methylene blue was achieved at optimal pH of 11, reaction time of 75 min, adsorbent dosage of 8 g/l and initial dye concentration of 10 mg/l. With increasing dye concentration from 10 to 100 mg/l, removal efficiency was decreased from 99.5% to 96.46%. The obtained data demonstrated that adsorption process of Methylene blue using peanut shell powder was well fitted with Langmuir isotherms (R2=0.894). Conclusion: Based on the results of the current study, the peanut shell seems to have an appropriate ability in Methylene blue dye removal from aqueous solution, and textile industry wastewater. [ABSTRACT FROM AUTHOR]

Highlights: [•] Polyphosphazene nanotube as an adsorbent could be facilely synthesized. [•] The adsorbent owns numerous electron-rich N and P atoms and hydroxyl groups. [•] The adsorbent was an efficient and specific adsorbent for the removal of MB. [•] The pseudo-second-order model could be better to describe the adsorption of MB. [•] The MB adsorption onto PZS nanotubes was endothermic and spontaneous. [Copyright &y& Elsevier]

In the present study adsorption behavior of methylene blue and rhodamine B from aqueous solution using adsorbent prepared from ' Hyptis suaveolens' (Vilayti Tulsi) was investigated as a function of parameters such as initial concentration, adsorbent dose, pH, contact time and temperature. The adsorption process was pH dependent. The thermodynamic parameters such as $$ {{\Updelta}}G,{{\Updelta}}H \,{\text{and}} \,{{\Updelta}}S $$ were calculated to investigate the nature of adsorption, their values indicate that the adsorption process is favorable. The first-order, second-order and intra-particle diffusion models were used to describe the kinetic parameter. The Freundlich and Langmuir adsorption models were applied to describe the adsorption equilibrium. Column study was conducted for both dyes. [ABSTRACT FROM AUTHOR]

Abstract: Equilibrium adsorption isotherm for the removal of basic dye (Methylene Blue) from aqueous solution using bituminous coal-based activated carbon has been investigated. Liquid phase adsorption experiments were conducted and the maximum adsorptive capacity was determined. The effect of experimental parameters, namely, pH and adsorbent particle size were studied. Equilibrium data were mathematically modelled using the Langmuir, Freundlich and Redlich–Peterson adsorption models to describe the equilibrium isotherms at different solution pH values and particle sizes, and isotherm constants were determined. The results indicate the potential use of the adsorbent for the removal of Methylene Blue (MB) from aqueous solution. Maximum adsorption capacity of 580mg/g at equilibrium was achieved. It was found that pH plays a major role in the adsorption process. The optimum pH for the removal of MB from aqueous solution under the experimental conditions used in this work was 11. The Redlich–Peterson isotherm was found to best fit the experimental data over the whole concentration range as indicating from the high values of the correlation coefficients (r 2 >0.99). [Copyright &y& Elsevier]