Hydrogels are a kind of unique cross-linking polymeric materials with three-dimensional networks. Various efforts have been devoted to manipulate the formation of functional hydrogels in situ and enrich the production...Hydrogels are a kind of unique cross-linking polymeric materials with three-dimensional networks. Various efforts have been devoted to manipulate the formation of functional hydrogels in situ and enrich the production of hydrogels, microgels and nanogels with improved modulation capacity. However, these methods always fail to tune the gel properties because of the difficulty in achieving the precise control of cross-linking extents once the gel formation is initiated. Therefore, the preparation of tailor-made hydrogels remains a great challenge. Herein, we summarize a controlled cross-linking strategy towards not only fabrication of hydrogels at nano-, micro-and macro-scales, but also achievement of controlled assembly of nanoparticles into multifunctional materials in macroscopic and microscopic scales. The strategy is conducted by controllably activating and terminating the disulfide reshuffling reactions of disulfide-linked core/shell materials with selective core/shell separation using system p H or UV triggers. So it provides a facile approach to producing hydrogels, hydrogel particles and nanoparticle aggregates with tunable structures and properties, opening up the design possibility, flexibility and complexity of hydrogels, microgels/nanogels and nanoparticle aggregates from nanoscopic components to macroscopic objects.展开更多
CTS-g-（AA-co-SS）/ISC hybrid hydrogel adsorbent with crosslinked network structure and superior adsorption performance for rare-earth metal ions was successfully synthesized in aqueous solution by a simple one-step f...CTS-g-（AA-co-SS）/ISC hybrid hydrogel adsorbent with crosslinked network structure and superior adsorption performance for rare-earth metal ions was successfully synthesized in aqueous solution by a simple one-step free-radical grafting polymerization reaction among acrylic acid（AA）, sodium p-styrenesulfonate（SS） and chitosan（CTS） using illite/smectite clay（ISC） as the inorganic additive. The structure of the as-prepared CTS-g-（AA-co-SS）/ISC hydrogel adsorbent was characterized, and the reaction parameters such as AA/SS molar ratio and ISC content were optimized, and the effects of pH values, initial concentration and contact time on the adsorption performance for Ce（Ⅲ） and Gd（Ⅲ） were systematically evaluated. It was found that the maximum adsorption capacities of the hydrogel adsorbent toward Ce（Ⅲ） and Gd（Ⅲ） reached 174.05 and 223.79 mg/g, respectively, and the adsorption quickly achieved equilibrium within 15–20 min. The adsorbed Ce（Ⅲ） and Gd（Ⅲ） could be easily desorbed for recovery, and the used adsorbent was able to be regenerated for reuse. After five adsorption-desorption cycles, the regenerated adsorbent could still retain the adsorption capacities that were close to the initial value. The adsorption process was well described by pseudo-second-order kinetic mode and the Langmuir isotherm model, and the chemical complexation between ions and –COO~–was mainly responsible for the high adsorption capacity. As a whole, the hybrid hydrogel adsorbent was potential to be used for the adsorption and recovery of Ce（Ⅲ） and Gd（Ⅲ） from water.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21674120,21504096,21474115 and 21174147)the‘Young Thousand Talents Program’
文摘Hydrogels are a kind of unique cross-linking polymeric materials with three-dimensional networks. Various efforts have been devoted to manipulate the formation of functional hydrogels in situ and enrich the production of hydrogels, microgels and nanogels with improved modulation capacity. However, these methods always fail to tune the gel properties because of the difficulty in achieving the precise control of cross-linking extents once the gel formation is initiated. Therefore, the preparation of tailor-made hydrogels remains a great challenge. Herein, we summarize a controlled cross-linking strategy towards not only fabrication of hydrogels at nano-, micro-and macro-scales, but also achievement of controlled assembly of nanoparticles into multifunctional materials in macroscopic and microscopic scales. The strategy is conducted by controllably activating and terminating the disulfide reshuffling reactions of disulfide-linked core/shell materials with selective core/shell separation using system p H or UV triggers. So it provides a facile approach to producing hydrogels, hydrogel particles and nanoparticle aggregates with tunable structures and properties, opening up the design possibility, flexibility and complexity of hydrogels, microgels/nanogels and nanoparticle aggregates from nanoscopic components to macroscopic objects.
基金Project supported by the National Natural Science Foundation of China(51403221,21377135,U1407114)the“863”Project of the Chinese Ministry of Science and Technology(2013AA032003)
文摘CTS-g-（AA-co-SS）/ISC hybrid hydrogel adsorbent with crosslinked network structure and superior adsorption performance for rare-earth metal ions was successfully synthesized in aqueous solution by a simple one-step free-radical grafting polymerization reaction among acrylic acid（AA）, sodium p-styrenesulfonate（SS） and chitosan（CTS） using illite/smectite clay（ISC） as the inorganic additive. The structure of the as-prepared CTS-g-（AA-co-SS）/ISC hydrogel adsorbent was characterized, and the reaction parameters such as AA/SS molar ratio and ISC content were optimized, and the effects of pH values, initial concentration and contact time on the adsorption performance for Ce（Ⅲ） and Gd（Ⅲ） were systematically evaluated. It was found that the maximum adsorption capacities of the hydrogel adsorbent toward Ce（Ⅲ） and Gd（Ⅲ） reached 174.05 and 223.79 mg/g, respectively, and the adsorption quickly achieved equilibrium within 15–20 min. The adsorbed Ce（Ⅲ） and Gd（Ⅲ） could be easily desorbed for recovery, and the used adsorbent was able to be regenerated for reuse. After five adsorption-desorption cycles, the regenerated adsorbent could still retain the adsorption capacities that were close to the initial value. The adsorption process was well described by pseudo-second-order kinetic mode and the Langmuir isotherm model, and the chemical complexation between ions and –COO~–was mainly responsible for the high adsorption capacity. As a whole, the hybrid hydrogel adsorbent was potential to be used for the adsorption and recovery of Ce（Ⅲ） and Gd（Ⅲ） from water.
