Adsorptive removal of noxious atrazine using graphene oxide nanosheets: Insights to process optimization, equilibrium, kinetics, and density functional theory calculations.

Bioremediation of phenolic pollutants by algae - current status and challenges.

Hydrodynamics and adsorption performance of liquid–solid fluidized bed with granular activated carbon for removal of copper ions from wastewater

Development of green, eco-friendly, and efficient adsorbents for wastewater treatment is highly researched to mitigate the alarming rate of water pollution. In this work, a novel biocomposite of biosilica (BS)/silk fibroin (SF)/polyurethane foam (PUF) was prepared and studied for the adsorptive recovery of toxic copper (Cu 2 + ) and chromium (Cr 6＋ ) ions from synthetic wastewater. XRD and FTIR studies confirmed the formation of biocomposite with amorphous structure and –OH, –NH, C=O surface functionalities. SEM results confirmed the successful incorporation of SF and PUF into BS. The biocomposite possessed a specific surface area of 751.9 m 2 /g and a mean pore size of 7.21 nm. Further, effects of pH, adsorbent dose, contact time, and initial metal ion concentration on the adsorptive removal of Cu 2 + and Cr 6＋ metal ions by the BS/SF/PUF biocomposite were studied in detail. Equilibrium and kinetic analysis showed that the metal ions sequestration by the BS/SF/PUF biocomposite followed the Freundlich isotherm and Elovich model, respectively. Maximum adsorption capacities of 331.69 mg/g and 201.56 mg/g were estimated for the Cu 2 + and Cr 6＋ ions, respectively. A plausible mechanism for the adsorption of the metal ions onto BS/SF/PUF biocomposite is postulated. Reusability studies of the biocomposite using EDTA eluent showed that the biocomposite could be efficiently reused up to four consecutive adsorption/desorption cycles. Thus, this study provides comprehensive data for applying the BS/SF/PUF biocomposite to treat Cu 2 + and Cr 6＋ metal ions polluted wastewater streams. • Amorphous BS/SF/PUF biocomposite was prepared through polymer blending. • Specific surface area and pore size of BS/SF/PUF were 751.9 m 2 /g and 7.21 nm. • High adsorptive removal efficiency of >80% for Cu 2+ and Cr 6+ heavy metal ions. • Freundlich isotherm & Elovich kinetic model best described adsorption operation. • BS/SF/PUF biocomposite was successfully reused up to 4 cycles through EDTA washing. 

Biosilica/Silk Fibroin/Polyurethane biocomposite for toxic heavy metals removal from aqueous streams

Effective adsorption of methylene blue from aqueous solution by coal gangue-based zeolite granules in a fluidized bed: Fluidization characteristics and continuous adsorption

A liquid-solid circulating fluidized bed (LSCFB) helps to overcome the shortcomings of conventional fluidized beds by using a particle separation and return system as an integral part of the overall reactor configuration. Batch adsorption experiments were carried out for the removal of phenol from a synthetically prepared solution using fresh activated-carbon-coated glass beads. The morphological features and surface chemistry of the adsorbent were analyzed via SEM and FTIR techniques. The adsorbent dosage, contact time and temperature were varied along with solution pH to assess their effects on the adsorbent performance for phenol removal. Isotherm modeling showed that the phenol removal using the activated-carbon glass beads followed the Langmuir model. Effectively, it was observed at an adsorbent loading of 2.5 g/150 mL of feed volume and a contact time of 3 h produced an 80% efficiency in the batch study. Furthermore, on scaling it up to the column, the desired 98% phenol-removal efficiency was obtained with an adsorbent dosage of 250 g and contact time of 25 min. Adsorbent regeneration using 5% (v/v) ethanol showed a 64% desorption of phenol from the sorbent within 20 min in the LSCFB.

https://www.mdpi.com/1996-1073/13/15/3839/pdf

Murugesan Thanapalan

Papers

Continuous Phenol Removal Using a Liquid–Solid Circulating Fluidized Bed