Ultrasound assisted batch operation for the adsorption of hexavalent chromium onto engineered nanobiocomposite

Abstract

The study demonstrates the comparative retention characteristics of chromium from aqueous environment on iron(III) cellulose nanocomposite bead under conventional (C-ads) and ultrasound assisted (U-ads) batch adsorption operation. Optimization of process parameters was achieved varying pH, contact/sonication time, initial Cr(VI) concentration, adsorbent dose at fixed solution temperature. Equilibrium was achieved within 5 h and 30 min of contact time in C-ads and U-ads respectively. Langmuir isotherm is found suitable in C-ads while Temkin in U-ads. Both the operation is aided by change in negative free energy, positive enthalpy and entropy. Ultrasound assisted adsorption is much favorable in terms of efficiency, feasibility, spontaneity and randomness. Both the operations follow more the second order than the first order kinetic model. The pore diffusion prevails more in case of U-ads while the surface adsorption in C-ads.

Adsorptive removal of Co(II) in aqueous solutions using clearing nut seed powder

“…With the increment of adsorbent dosage, more metal ions got removed from the solution as more binding sites are available for the binding of Co(II) ions along with increased specific surface area [48]. Beyond 0.3 g further increment in CNSP dosage didn't show considerable effect on the percentage removal due to the overlapping of binding sites and the aggregate formation of the adsorbents at high adsorbent dosage levels [36,49]. binding sites available on the adsorbent by enhancing the porosity of the adsorbent and by reducing the organic matter content [50].…”

2-Mercaptobenzimidazole derivative of chitosan for silver sorption – Contribution of magnetite incorporation and sonication effects on enhanced metal recovery

“…This slope is frequently associated with proton exchange in mechanisms involving ion-exchange reactions. In the present case, the slopes are not coherent with possible porous network) and locally affect the internal porosity of the sorbents [43,[64][65][66][67]. Increasing the frequency, at least within selected frequency range (i.e., 37-80 kHz) improves the sorption of silver: kinetic profiles are systematically shifted to lower residual concentrations at equilibrium.…”

Ligustrum lucidum Leaf Extract-Assisted Green Synthesis of Silver Nanoparticles and Nano-Adsorbents Having Potential in Ultrasound-Assisted Adsorptive Removal of Methylene Blue Dye from Wastewater and Antimicrobial Activity

“…This trend was similar to that reported in the literature for dye adsorption from aqueous solution [ 60 , 70 ]. However, in the sono-adsorption process, ultrasonic irradiation might increase the mass transfer rate of solute around the solid–liquid interfaces because of the high-pressure shock waves in the violent collapse of cavitation bubbles [ 71 ]. Thus, sonication develops equilibrium in a short time than the conventional operation.…”