Design of Crosslinked Hydrogels Comprising Poly(Vinylphosphonic Acid) and Bis[2-(Methacryloyloxy)Ethyl] Phosphate as an Efficient Adsorbent for Wastewater Dye Removal

Abstract

The development of adsorbents with high adsorption capacity and fast separation is of utmost importance for the environmental management of dye-bearing wastewaters. Within this scope, crosslinked hydrogels including poly(vinylphosphonic acid) (PVPA) and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) were designed with varying mole ratios of BMEP (5–40%). The Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) results revealed that the fabrication of crosslinked PVPA-BMEP hydrogels enhanced: (i) functionalities of PA groups in the structure of hydrogels, (ii) thermal stabilities up to 250 °C, and (iii) interaction between methylene blue (MB) molecules and hydrogels. The pseudo second-order kinetic model best described the experimental adsorption data. The behaviors of the isotherms were more appropriate for Langmuir than Freundlich isotherm for the experimental data. PVPA-BMEP (40%) hydrogel indicated a fast and an outstanding MB adsorption capacity of 2841 mg g−1, which has not been reported yet for polymer hydrogels, to the best of our knowledge. The thermodynamic studies concluded that MB adsorption process was spontaneous and exothermic in nature. The overall results suggest that the designed and fabricated PVPA-BMEP hydrogels have great potential for the efficient removal of coloring materials from wastewaters.

Magnetic Mg-Fe/LDH Intercalated Activated Carbon Composites for Nitrate and Phosphate Removal from Wastewater: Insight into Behavior and Mechanisms

“…The effect of temperature on the adsorption of phosphate and nitrate onto the SBAC 100 MgFe composite was studied at three different temperature values of 298, 308, and 318 K. The adsorbed amounts of phosphate and nitrate ions increased by 2.90% (pH 3), 9.79% (pH 6), 7.61% (pH 3), and 31.6% (pH 6), respectively, when the solution temperature increased from 298 to 318 K, suggesting the endothermic nature of the adsorption process. The thermodynamic parameters, such as standard free Gibbs energy (Δ G ), standard enthalpy change (Δ H ), and standard entropy change (Δ S ), were further computed in order to reveal the adsorption mechanism and feasibility of the adsorption by using the van’t Hoff equations (Equations (3) and (4)) [ 22 , 49 , 50 ]. where K d is the thermodynamic equilibrium constant calculated by plotting ln( q e / C e ) against q e and extrapolating q e to zero; R is the universal gas constant (8.314 J/mol K); T is the absolute temperature (K).…”

Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field

“…Each method shows advantages or disadvantages depending on different factors such as dye chemical features, dye concentration, presence of additional impurities, cost of the process [41]. Here, we aim to explore the key advantage of adsorption methods, defined by the United States Environmental Protection Agency as one of the most excellent and best wastewater treatment techniques [42], by coupling the surface properties of CNT, the water affinity and eco-compatibility of acrylate hydrogels with the possibility to affect the sorbent properties by applying an external electric field. Moreover, such materials can open new opportunities for a multi-technique approach: when formulated into hydrogel films, they can be also used in membrane filtration process, another efficient and economically effective approach for wastewater remediation [43], while the intrinsic electrical and photothermal properties of CNT, together with the possibility to decorate their surface with suitable catalysts, can open the possibility to use the hybrid hydrogel as a substrate for chemical methods [44].…”

Synthesis of Crosslinked Poly(Vinylphosphonic Acid) Particles by Water-in-Oil (W/O) Suspension Polymerization Method and Their Adsorption Properties of Metal Ions

“…Anil et al reported dyes adsorption onto crosslinked PVPA [17]. However, the existing literature indicates that there is no report on the adsorption capabilities of PVPA-based particles for transition metal ions and lanthanoid ions.…”