Degradation of gaseous formaldehyde by controlled release of NaClO2 composite gel microspheres
Formaldehyde is one of the most important indoor VOC pollution sources,and it is often ad-sorbed by porous materials.However,these adsorbent materials have limited adsorption capacity and service life.Sodium chlorite(NaClO2)releases chlorine dioxide(ClO2)under acidic conditions,which can oxidize formal-dehyde to carbon dioxide.Meanwhile,NaClO2 is prone to moisture absorption and decomposition,it is ex-tremely unstable under conventional conditions.NaClO2 composite gel microspheres were prepared by emul-sion crosslinking method with NaClO2 as core material and high biocompatible natural polymer materials sodi-um alginate(SA)and sodium carboxymethyl cellulose(CMC-Na)as wall material to improve their stability and slow release performance.The morphology,functional groups and thermal properties of the obtained micro-spheres were characterized by SEM,DLS,FTIR and TGA,and the ability of NaClO2 composite gel micro-spheres to remove gaseous formaldehyde was evaluated by degradation experiments.The results showed that the prepared NaClO2 composite gel microspheres were structured and spherical,with an average particle size of 662.5 nm,and had good thermal stability.When the pH was 6.5 and the initial mass concentration of formaldehyde was 4 mg/m3,the 250 mg NaClO2 composite gel microspheres showed the ability of continuous degradation of formaldehyde,and the degradation rate of formaldehyde reached 60.00%in the first 5 min and 90.45%in 30 min.It could be seen that NaClO2 composite gel microspheres were expected to be used in air conditioning filters or interior decoration textiles to adsorb formaldehyde and purify indoor air.
emulsion crosslinkingcomposite gel microspheresformaldehyde degradationcontrolled release
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