Isotherm study of banana stem waste adsorbents to reduce the concentration of textile dying waste

The purpose of this study was to make carbon from banana stem waste and determine the isotherm adsorption characteristics of carbon from banana stem waste to methyl orange compounds. The process for making carbon from banana stem waste was done through the stages of preparation and carbonization at a temperature of 250°C for 1.5 h. Before being used as carbon, banana stem waste was cleaned, washed, dried, and mashed using a mill. The carbon then went through a washing process to remove impurities and tested for its absorbance ability into a solution containing a methyl orange compound under constant conditions of pH, temperature, and pressure. The experimental results showed that the appropriate sequence of adsorption models is the Langmuir, Temkin, Freundlich, and Dubinin-Radushkevich models. Adsorption occurs on the surface of a single layer (monolayer) and the interaction between the adsorbent and the adsorbate occurs physically. The value of maximum adsorption capacity (Qmax) is 37.5940 mg/g. The presence of banana stem carbon is expected to reduce the negative impacts, one of which is the disposal of industrial wastewater from textile factories.

Fabrication of GO/PAN Nanofiber Membrane Grafted With Chitosan As Efficient Adsorbent For Dye Removal

The adsorption is widely used to remove dyes from wastewater because of its low cost, simple preparation, and environmental friendliness. However, the existing adsorbents suffer from difficult recycling, inconvenient use, and low regeneration rate. In this study, polyacrylonitrile (PAN) and graphene oxide (GO) was mixed for electrospinning GO/PAN nanofiber membrane and then chitosan (CS) was grafted to obtain CS-GO/PAN nanofiber membrane. CS-GO/PAN membrane were characterized with FE-SEM, EDX, FT-IR and, WCA. The effects of membrane types, dosage, solution pH on the removal of dye sunset yellow (SY) were systematically investigated. The results showed that more than 80% of SY were removed within 15 min at pH 2 using 100 mg CS-GO/PAN membrane. Adsorption kinetic data were fitted well with the pseudo-second-order model and adsorption equilibrium achieved within 240 min. The isotherm study followed the Langmuir model with the actual maximum adsorption capacity of 211.54 mg/g. After 5 adsorption-desorption cycles, the adsorption efficiency and the desorption efficiency of CS-GO/PAN were over 90% and 93%, respectively. Moreover, the membrane recovered easily from the water while its integrity was still maintained. The CS-GO/PAN membrane demonstrates the virtue of high adsorption capacity, easy operation, and good reusability, which could be considered as a promising material for adsorbing dyes in wastewater.

Adsorption Kinetics and Isotherm Study of Basic Red 5 on Synthesized Silica Monolith Particles

The Silica monolith particles (SMP) were prepared from Tetra-Methyl-Ortho-Silicate (TMOS) and characterized by Fourier transforms infrared (FTIR), Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and surface area analyzer. FTIR analysis showed the Si−O stretching confirming SMP formation. SEM analysis provided information about the mean diameter of SMP (1−5 µm). EDX confirmed the presence of silicon and oxygen in the SMP. Moreover, the calculated surface area for SMP was found to be around 367 m2/g, whereas BJH pore size distributed particles were 87.15 along with the total pore volume and pore radius of 0.073 cm3/g and 16.627 Å, respectively. Besides, the removal efficiency was found to be about 96%. Various kinetic equations were used to calculate the adsorption parameters. Overall, the results show that the most appropriate model for the kinetics data was the pseudo-second order kinetics model while the mechanism of adsorption was best explained by the Langmuir isotherm. The highest removal of Basic Red 5 dye after 120 min at 298 K was 576 mg/g. Moreover, the thermodynamics parameters (Enthalpy, Gibb’s energy, and Entropy) were also estimated. The ΔH° (0.995 kJ/mol) value depicted the endothermic nature of the process. The non-spontaneous aspect of the process was evident from the ΔG° values which were 60.431, 328.93, and 339.5 kJ/mol at 293, 303, and 313 K, respectively. From the high removal efficiency value, it can be concluded that the prepared adsorbent can be a potential adsorbent in the reclamation of dyes from wastewater.

Adsorption Isotherm Study of Cd (II), Ni (II) and Cu (II) Removal in Ternary System Using Nano ϒ-Al2O3

The adsorption of Cd (II), Ni (II) and Cu (II) ions on nanoϒ-Al2O3 isotherms study indicate that (Langmuir, Freundlich and Elovich) be the most excellent model described removal of Cu (II) ion. Jovanovic and Harkins-Jura were found to be the most excellent one described removal of Ni (II) ions and the all models are less suitable for Cd (II) ions. All these were noted from the correlation coefficients values. The highest removal percentages obtained for ions were 92.045 % of Cd (II), 93.175 % of Ni (II) and 93.685% of Cu (II). FESEM was measured to find out the average particle size of nanoparticles and EDXA was used for measuring purity.

Methylene Blue and Iron (II) Adsorption onto Raphia Hookeri Seed: A Comparative Equilibrium Isotherm Study

In this study, activated carbon prepared from Raphia hookeri seed was employed as an adsorbent to take up methylene blue (an organic ion-in-solution) and iron (II), a metal ion-in-solution. The biosorbent was prepared using chemical activation using sodium hydroxide (NaOH) as an impregnating agent. Calibration was performed with a focus on the change in the adsorbate concentration. The equilibrium isotherms study was conducted by considering a range of sorbate concentrations, to determine the optimal conditions for the adsorption systems. The same sorbate volume (10 ml), and the same dosage (0.3g) of biosorbent were used for both adsorption processes. Linear analysis was used to compare the best-fitting isotherms. Langmuir, Freundlich, and Dubinin-Radushkevich models were tested. The highest coefficient of determination values (R2) for both iron (II) and Methylene blue was obtained from the Langmuir isotherm as 0.9266 and 0.9572, respectively, compared to values from the other isotherms tested – indicative of Langmuir isotherm’s superior fit. Estimated values of ‘separation factor’, KR, for Methylene blue (0.29457), however, was lower than that of iron (II) (0.42141) - an indication that the sorbent treats methylene blue better than iron (II), though both processes are feasible.