Optimization of Crystal Violet Dye Removal in Fixed Bed Column Using Eucalyptus camaldulensis as a Low-Cost Adsorbent

Adsorption through waste adsorbents is one of the developing technologies used for treating textile wastewater. The present study explores the possible outcome of Eucalyptus camaldulensis biomass as an adsorbent for removing crystal violet dye from aqueous solutions. Eucalyptus camaldulensis biomass was used as such and used in fixed bed column mode to testify its potential at different parameters. Effect of different constraints like bed height (cm), flow rate (mlmin-1), initial dye concentration (mgL-1), and pH were studied along with breakthrough curve and exhaust time. Maximum breakthrough curve and exhaust time and utilization of mass transfer zone were observed at bed height of 20 cm. However, the promising results are obtained at higher dye concentration (50 mgL-1), lower flow rate (1 mlmin-1), and at lower pH of 5. This study reveals promising results at acidic pH. This study reflects that adsorption capacity and breakthrough curve favor lower acidic pH. The adsorption data in batch mode follow the Langmuir isotherm and best fit to pseudo-second-order reaction kinetics. The breakthrough curve and mass transfer zone are individually testified, and the breakthrough curve obeys the assumptions of the Thomas model, and R2 (0.933-0.997) values confirm the data that its best fit with the Thomas model.

Use of low-cost adsorbent derived from the brazilian cerrado biome to remove pollutants in effluent

The biochar of the Pequi peel represents a sustainable alternative in the process of treating effluents through adsorption system. This study investigates the adsorption capacity in a fixed bed column of the activated biochar from pequi peel (ABPP) to remove the components. The biochar was obtained by pyrolysis, which was activated with zinc Chloride - ZnCl₂. Through the Thomas model, it was found that the concentration of Paracetamol of 5 mg L-1 obtained 3.21 mg g-1 of drug adsorption, which was higher than the adsorption obtained with the concentrations of 10 mg L-1 (3.02 mg g-1) and 20 mg L1 (1.22 mg g-1). Methylene blue was tested with a concentration of 3 mg L-1, adsorbing 8.07 mg g-1. The data fit the Thomas model with an R² higher than 0.90. The capacity of ABPP to adsorb methylene blue and Paracetamol was satisfactory, with adsorbing significant.

Removal of Cr (VI) from aqueous solution by activated charcoal derived from Sapindus trifoliate L fruit biomass using continuous fixed bed column studies

In this study, the removal of hexavalent chromium from aqueous solution were examined using activated charcoal derived from Sapindus trifoliate L fruit biomass in continuous fixed-bed column studies. The activated S. trifoliate L fruit charcoal was prepared by treating the fruit powder using concentrated nitric acid solution. Experiments were performed to investigate the effect of bed-height and initial concentration on the breakthrough and saturation times. The breakthrough and saturation time increases with increase in bed-height and initial concentration of chromium solutions. The maximum adsorption capacity of S. trifoliate L charcoal for hexavalent chromium was found to be 1.719 mg/g in the bed height 15 cm and initial concentration 10 mg/L, respectively. Column data required at various conditions were explained using Bohart-Adams and Thomas model. Two models were found to be suitable to describe the definite part of the dynamic behaviour of the column with regard to bed-height and initial concentration of hexavalent chromium. On comparison of Adjusted R2 and estimated standard error, the Thomas model was found to best-fitted model and can be used to predict the adsorption of the hexavalent chromium in fixed-bed column studies. Activated Sapindus trifoliate L fruit charcoal was characterised by SEM – EDX and FTIR analysis.

Evaluating the response of a modified Gent-Thomas strain energy function having limiting chain extensibility condition in torsion and azimuthal shear

The purpose of this paper is to investigate the torsion and azimuthal shear of an incompressible hyperelastic cylinder having a modified Gent-Thomas strain energy with limiting chain extensibility condition. First, the torsional response of the modified Gent-Thomas model is obtained analytically and compared with those of Gent-Gent, Gent-Thomas, and Carroll strain energy models where the former model incorporates the limiting chain extensibility condition while the latter two are phenomenological models. The results show the modified Gent-Thomas model to be in better agreement with the experimental data of Rivlin and Saunders on torsion than the other three models. To further evaluate the response of the modified Gent-Thomas model, azimuthal shear deformation of an incompressible hyperelastic cylinder with the modified Gent-Thomas, Gent-Thomas, Gent-Gent, and Carroll strain energies is considered, where the angular displacement in azimuthal shear is determined analytically for the first three models and numerically for the fourth model. It is shown that the strain hardening effect, predicted either by the limiting chain extensibility condition for the modified Gent-Thomas and Gent-Gent models or phenomenologically by the Carroll model, is quite significant in the azimuthal shear response of the incompressible cylinder.

Anaerobically fermented spent mushroom substrates improve nitrogen removal and lead (II) adsorption

In this study, spent mushroom substrates (SMSs) were fermented anaerobically at room temperature to gain liquid SMSs (LSMSs) that were used to remove nitrogen from the piggery wastewater with a low C/N ratio in a sequencing batch reactor (SBR) and solid SMSs (SSMSs) that were utilized to adsorb Pb2+ from Pb2+-containing wastewater in a fixed-bed reactor (FBR). After LSMSs supplement, the removal efficiency of both total nitrogen (TN) and NH+4-N increased from around 50% to 60–80%. High-throughput sequencing results presented an obvious change in microbial diversity, and some functional microorganisms like Zoogloea and Hydrogenophaga predominated to promote nitrogen removal. Pb2+ did not emerge from the effluent until 240 min with the corresponding concentration being less than 3 mg/L when using 30-day SSMSs as adsorbents, and it was demonstrated to be appropriate to use the Thomas model to predict Pb2+ sorption on SSMSs. Although various functional groups played a role in binding ions, the carboxyl group was proved to contribute most to Pb2+ adsorption. These results certified that the anaerobically fermented SMSs are decidedly suitable for wastewater treatment.

Removal of Cu(II) by Fixed-Bed Columns Using Alg-Ch and Alg-ChS Hydrogel Beads: Effect of Operating Conditions on the Mass Transfer Zone

The removal of Cu(II) ions from aqueous solutions at a pH of 5.0 was carried out using fixed-bed columns packed with alginate-chitosan (Alg-Ch) or alginate-chitosan sulfate (Alg-ChS) hydrogel beads. The effect of the initial Cu(II) concentration, flow rate, pH, and height of the column on the amount of Cu removed by the column at the breakpoint and at the exhaustion point is reported. The pH of the solution at the column’s exit was initially higher than that at the entrance, and then decreased slowly. This pH increase was attributed to proton transfer from the aqueous solution to the amino and COO− groups of the hydrogel. The effect of operating conditions on the mass transfer zone (MTZ) and the length of the unused bed (HLUB) is reported. At the lower flow rate and lower Cu(II) concentration used, the MTZ was completely developed and the column operated efficiently; by increasing column height, the MTZ has a better opportunity to develop fully. Experimental data were fitted to the fixed-bed Thomas model using a non-linear regression analysis and a good correspondence between experimental and Thomas model curves was observed.

Column Experiments for Removal of Copper from Wastewater using Activated Carbon Coated with Tio2 Nanoparticles

The study reports application of activated carbon coated with TIO2 nanoparticles to remove Copper from wastewater. The TiO2 nanoparticles are synthesized using sol-gel process and are coated on Granular Activated Carbon (GAC) using Bisphenol resin as adhesive. The synthesized composite material is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Column experiments are conducted to investigate removal of copper from industrial effluent by varying flow, height and mass of adsorbent. Results showed decrease in the heavy metal and sorption is well explained by Thomas model.