Effective Adsorption–Desorption Kinetic Study and Statistical Modeling of Bentazon Herbicide Mediated by a Biodegradable β-Cyclodextrin Cross-Linked Poly(vinyl alcohol)–Chitosan Hydrogel

Abstract

Indiscriminate use of pesticides to meet the global demand for food has contaminated groundwater and surface water, affecting the global environment. In view of this, it is imperative to find an economical solution to this critical issue. Herein, a novel β-cyclodextrin cross-linked poly(vinyl alcohol)−chitosan (PVA/CS/β-CD) hydrogel is reported for the adsorption of bentazon (BZ) herbicide. The properties of the PVA/CS/β-CD hydrogel, such as its surface morphology, surface area, thermal stability, and the presence of functional groups, have profound effects on the adsorption of BZ on its surface, and hence these have been investigated by FESEM, BET, TGA, and FT-IR analytical techniques. Several influential factors, viz., pH of the solution, temperature, initial concentration of BZ, contact time, and mass of the hydrogel, have been explored by the Box−Behnken design model and systematic batch studies. From the response surface methodology model, 13.45 mg of hydrogel was able to remove 93.71% of BZ from 10 mL of a 10 mg/L solution at pH 7.4 in 120 min, as assessed by systematic batch adsorption studies. The adsorption behavior of BZ on the PVA/CS/β-CD hydrogel was thermodynamically spontaneous and endothermic. The maximum adsorption capacity was 398.40 mg/g, which comes from the Langmuir isotherm and follows pseudo-second-order model. BZ-loaded PVA/CS/ β-CD hydrogel can be recycled using methanol and shows good removal efficiency (>70%) for six consecutive adsorption− desorption cycles. Additionally, the BZ-adsorbed PVA/CS/β-CD hydrogel can be employed as a sustained release vehicle for BZ having long-term weedicide effects at diverse pH values in water.

Synthesis and Characterization of Environmentally Friendly β-Cyclodextrin Cross-Linked Cellulose/Poly(vinyl alcohol) Hydrogels for Adsorption of Malathion

“…The adsorption possibly involved the formation of covalent bonds between sulfur (S) atoms in malathion and oxygen (O) atoms of β-CD, cellulose, PVA, and ECH on the hydrogel . Additionally, the CO groups in malathion could form hydrogen bonds with the OH groups of β-CD, cellulose, PVA, and ECH, while electrostatic interactions between the CO groups in malathion and hydrogen (H) atoms of cellulose may occur . Furthermore, the hydrophobic groups such as P-OCH 3 and OC 2 H 5 groups of malathion could be trapped within the cavity of β-CD through hydrophobic interactions .…”

“…This result can be attributed to the introduction of more active sites on the hydrogel surface, consequently enhancing the adsorption of malathion. 26,50 2.5. Effect of pH on Malathion Adsorption Capability.…”

Evaluation of Adsorptive Capture and Release Efficiency of MNPs-SA@Cu MOF Composite Beads Toward U(VI) and Th(IV) Ions from an Aqueous Media

“…To determine the adsorption mechanism and rate of adsorption of U­(VI) and Th­(IV) ions onto MNPs-SA@Cu MOF composite beads, the linear and nonlinear equations of two kinetic models, pseudo first order and pseudo second order were applied on the adsorption process. , The equations of both kinetic models are presented in Supporting Information (Text S2 and eqs S5–S8). Figure S8a–d displays the linear fitted kinetic model graphs of U­(VI) and Th­(IV) ions and Figure S9a,b shows the nonlinear kinetics fitted models.…”

Polyoxometalate nanocluster-infused triple IPN hydrogels for excellent microplastic removal from contaminated water: detection, photodegradation, and upcycling

“…The initial stage was attributed to moisture loss from the hydrogel compound, while the subsequent stage was linked to the degradation of polysaccharide chains in chitosan. 19,54 Interestingly, the TGA results showed no notable alteration in thermal stability when comparing the hydrogel formulations before and after the integration of Cu-POM nanoclusters. The result underscores the confirmed The persistence of thermal stability despite the addition of Cu-POM nanoclusters suggests a synergistic relationship between the intrinsic stability of the hydrogel's IPN structure and the added stability contributed by the Cu-POM nanoclusters.…”