New and innovative microwave-assisted technology for synthesis of guar gum-grafted acrylamide hydrogel superabsorbent for the removal of acid red 8 dye from industrial wastewater

Abstract

The goal of this study is to develop a new effective guar gum-grafted acrylamide hydrogel for wastewater treatment, abbreviated as (guar gum-g-acrylamide). For the non-biodegradable and hazardous synthetic acid red 8, the produced guar gum-g-acrylamide hydrogel is a promising thermally stable adsorbent. Microwave-aided technique, ammonium persulfate initiator, and N,N′-methylene-bis-acrylamide cross-linker are used to make a hydrogel comprising natural polysaccharides guar gum grafted by poly acrylamide. Fourier transformer infrared (FTIR) spectra and scanning electron microscopy (SEM) demonstrate that varied percentages of acrylamide successfully graft the backbone of guar gum. When the grafting percentage of acrylamide is raised, the hydrogel’s maximum adsorption capacity (qe) increases. At pH 1 of dye solution, maximum adsorption capacity (qe) is 18 mg.g−1, at pH 9; qe is decreased up to 8 mg.g−1. At 0.5 g.L−1 hydrogel, the dye has a low removal percentage (34%), but when the hydrogel dosage is increased to 8 g.L−1, the removal percentage increases to 90%. When the initial AR8 dye concentration was increased from 50 to 300 mg.L−1, the removal percentage reduced to 20% and the adsorbed quantity dye increased from 17 to 44 mg.g−1, but both parameters became limited above this dye concentration. Other ideal conditions for AR8 dye removal by the hydrogel include 60 min of contact time, 150 revolutions per minute (rpm), and a temperature of 20 degrees Celsius. The AR8 dye adsorption kinetic is pseudo-second order, assuming electrostatic interaction between the negatively charged AR8 dye molecules and the positively charged hydrogel-functional group. The adsorption values fit the Langmuir isotherm, with qmax. of 54.054 mg.g−1. The adsorbed quantity (qe) decreases as the temperature rises, indicating that dye molecules physisorbed on the hydrogel pores, and the maximum adsorption capacity is at 20 °C. The exothermic and spontaneity of adsorption were confirmed by the negative values of heat of adsorption (∆H°ads.) and standard Gibbs free energy of adsorption (∆G°ads.). The reusability of the hydrogel was validated after three cycles of desorption of AR8 dye from the hydrogel surface in alkaline solution.

Adsorption and decolorization study of reactive black 5 by immobilized metal–organic framework of UiO-66 andGloeophyllum trabeumfungus

“…According to Batouti et al , the process is physisorption if the Δ H value is −4 to −40 kJ mol −1 and classified as chemisorption if −40 to −800 kJ. 57 Based on this classification, adsorption properties of UiO-66 and UiO-66/GT@PVA-SA tend to follow the type of physisorption. While the positive value of entropy (Δ S ) indicates the degree of disorder of the adsorbate at the solid–liquid interface has increased during adsorption process.…”

Formulation of promising antibacterial, anticancer, biocompatible and bioactive biomaterial as therapeutic drug delivery system for biologically active compound loaded on clay polymer

“…Stepwise hydration of interlayer cation in MMT enabled intercalation with positively charged molecules. Although many adsorbents are reported for removal several pollutants from aqueous solution: Cd +2 and Pb +2 [20,21], Cr(VI) ion [22][23][24][24][25][26][27][28][29]; pb(II) ions [30,31], reactive dyes [32,33], MMT clay bisorbent for adsorption of 5-[4-bromobenzylidene amino)-1, 3, 4-thiadiazole-2-thiol (BATT) is not reported yet, ecofriendly and keeping environmental safety, biodegradability, availability, etc.…”

Nanocellulose-Based Ecofriendly Nanocomposite for Effective Wastewater Remediation: A Study on Its Process Optimization, Improved Swelling, Adsorption, and Thermal and Mechanical Behavior

“…It is noteworthy that the hydrogel with a higher SI was achieved along with enhanced q e in comparison to the earlier reported results. 4,17 3.2. Unreacted BX Estimation.…”

“…Several GG-based hydrogels have been reported for the removal of dye pollutants from wastewater, such as aniline dye, 15 Congo red dye, 16 Acid Red 8 (AR8) dye, 17 crystal violet, azure B dye, 18 etc. The efficient adsorption of MB dye has also been explored through GG-based hydrogels, such as the TiO 2 -embedded GG hydrogel (R % = 96%), 19 PANIincorporated GG-acrylic acid (SI = 1376%; R = 88%)-based cross-linked hydrogel, 20 galactomannan acrylamide-octadecyl methacrylate hydrogel (SI = 2340%; q e = 19.3 mg g −1 ), 21 and GG-poly(acrylic acid−aniline)-based interpenetrating hydrogel network (SI = 2345.06%; R % = 93.87%) 22 but with limited swelling and adsorption or dye removal capabilities.…”