Adsorption of tetrodotoxin by flexible shape-memory polymers synthesized from silica-stabilized Pickering high internal phase emulsion

Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.

Facile synthesis of metal-organic frameworks embedded in interconnected macroporous polymer as a dual acid-base bifunctional catalyst for efficient conversion of cellulose to 5-hydroxymethylfurfural

5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.