Hydroxypropyl methylcellulose based aerogels: Synthesis, characterization and application as adsorbents for wastewater pollutants

Hydroxypropyl methylcellulose (HPMC) E4M and J5MS samples with degrees of substitution of methyl groups (DS) 1.9 and 1.5, respectively, and molar substitutions of hydroxypropyl groups (MS) 0.25 and 0.75, respectively, were used to create aerogels in the presence of citric (cit), oxalic (oxa) or terephthalic (ter) acids, as crosslinkers. E4M-cit, J5MS-cit and J5MS-oxa aerogels presented outstanding stability in water, acid media, alcohols, acetone and hydrocarbons, density values of similar to(0.020 +/- 0.002) g/cm(3), compressive modulus ranging from (111 +/- 9) kPa to (133 +/- 11) kPa. On the other hand, E4M-oxa, E4M-ter and J5MS-ter aerogels were not adequate adsorbents because they collapsed in water. The adsorption behavior of 17 alpha-ethinyl estradiol (EE) and methylene blue (MB) onto E4M-cit, J5MS-cit and J5MS-oxa aerogels were fitted to Freundlich model, indicating higher affinity of EE for J5MS-cit and J5MS-oxa and higher affinity of MB for E4M-cit aerogels. HPMC aeorogels could be successfully reused. (C) 2016 Elsevier Ltd. All rights reserved.