Facile Preparation and Dye Adsorption Performance of Poly(N-isopropylacrylamide-co-acrylic acid)/Molybdenum Disulfide Composite Hydrogels

Abstract

Using N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) as monomers, N,N′-methylenebisacrylamide (MBA) as a cross-linking agent, and molybdenum disulfide (MoS 2 ) as functional particles, a P(NIPAM-co-AAc)/MoS 2 composite hydrogel was prepared by free radical polymerization initiated by ultraviolet light. The results of Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy show that MoS 2 has been successfully introduced into the P(NIPAM-co-AAc) system, and the obtained composite hydrogel has a porous network structure. Studies on the swelling property and dye adsorption performance show that the addition of MoS 2 can increase the swelling ratio of P(NIPAM-co-AAc) hydrogels to a certain extent and can significantly improve the ability of the P(NIPAM-co-AAc) hydrogel to adsorb methylene blue (MB). The adsorption process of MB by the composite hydrogels conforms to the pseudo-secondorder kinetics and the Langmuir isotherm adsorption models. The estimated equilibrium adsorption capacity (Q m ) using the Langmuir isotherm model can reach 1258 mg/g, mainly due to the electrostatic interaction between the negatively charged groups −COO − and MoS 2 particles on the network structure and the positively charged dye MB. The adsorption of MB by P(NIPAM-co-AAc)/MoS 2 composite hydrogels depends on the temperature during adsorption. Compared with room temperature, a high temperature of 40 °C above the poly(N-isopropylacrylamide) (PNIPAM) phase transition temperature (∼32 °C) leads to a decreased adsorption capacity of the P(NIPAM-co-AAc)/MoS 2 composite hydrogel for MB due to the enhanced hydrophobic properties of the network structure and the decrease of the swelling ratio. The prepared hydrogel material can be used as a good adsorbent for dyes, which is promising in wastewater treatment.

The Effect of Silver Nanoparticles/Titanium Dioxide in Poly(acrylic acid-co-acrylamide)-Modified, Deproteinized, Natural Rubber Composites on Dye Removal

“…The interaction between active sites of adsorbents and MB molecules occurred through hydrogen bonding from -NH 2 groups of PAM and N atoms of MB molecules [ 12 ]. In addition, the carboxylate ions of PAA can also interact with positively charged MB through electrostatic attraction [ 59 ]. According to the Langmuir equation, the essential factor of the Langmuir isotherm (R L ) corresponds to the type of adsorption behavior.…”

Preparation and self-assembly of ionic (PNIPAM-co-VIM) microgels and their adsorption property for phosphate ions

“…According to different external inuence factors, environmentally sensitive microgels can be divided into temperature-responsive microgels, magnetic-responsive microgels, pressure-responsive microgels, near-infrared laser-responsive microgels, pH-responsive microgels, and multi-responsive microgels. [8][9][10][11][12][13][14][15][16] Nowadays, microgels have many applications in dye and ion sensing and adsorption, such as selective adsorption of metal ions, such as Ni 2+ , Cu 2+ , Co 2+ , Pb 2+ , and dye molecules, [17][18][19][20][21][22][23][24] but there are few reports on the adsorption of phosphate ions. 25,26 Phosphorus discharged into water can easily lead to eutrophication, and phosphorus-containing wastewater discharged into soil will cause soil zinc deciency.…”