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

Ismail Anil,Omar Alagha,Ayhan Bozkurt,Seyda Tugba Gunday

doi:10.3390/nano10010131

Ismail Anil, Omar Alagha + Show 2 more

Open Access

https://doi.org/10.3390/nano10010131

Copy DOI

Journal: Nanomaterials	Publication Date: Jan 10, 2020
Citations: 21	License type: CC BY 4.0

Affiliation: Imam Abdulrahman Bin Faisal University

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.

Highlights

The discharge of dye-bearing wastewaters arising from various industries such as textile, paper, printing, and leather into surface waters and groundwater is one of the most important environmental concerns due to the harmful effects on public health and the aquatic environment [1,2]
The declines in the slopes become more notable as the bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) fraction of the hydrogel decrease. These adsorption capacity tendencies of the hydrogels are supported by the results shown in Figure 6a–c where the methylene blue (MB) removal efficiencies of hydrogels decrease as the C0 value increases
The crosslinker bis[2-(methacryloyloxy)ethyl] phosphate was used in the synthesis of Poly(vinylphosphonic acid) (PVPA) hydrogels adsorbent via free-radical polymerization of vinylphosphonic acid (VPA)

Summary

Introduction

The discharge of dye-bearing wastewaters arising from various industries such as textile, paper, printing, and leather into surface waters and groundwater is one of the most important environmental concerns due to the harmful effects on public health and the aquatic environment [1,2]. The treatment process of synthetic dyes is a challenging task because of their complex, inert, non-biodegradable, and toxic structures [4,7]. Several methods, including adsorption, ion exchange, chemical coagulation, flotation, chemical oxidation, membrane filtration, reverse osmosis, ozonation, and photochemical degradation, have been used to treat synthetic dyes in wastewaters [1,8,9,10,11,12,13,14,15]. Adsorption has been proven to be a promising dye treatment process due to its substantial efficiency, simplicity, low cost, fast adsorbate/adsorbent contact time, etc. Disadvantages of the adsorption process are the regeneration capacity and regeneration cost of the adsorbent, biodegradability and disposal of the end-of-life adsorbent [18]

Methods

Results

Conclusion