Synthesis conditions of porous clay heterostructure (PCH) optimized for volatile organic compounds (VOC) adsorption

Volatile organic compounds (VOCs) can cause carcinogenic risk, odor problems, and even generation of particulate matter. Adsorption is an effective technique for controlling VOC emissions at the source. In this study, porous clay heterostructure (PCH) was considered as a possible VOC adsorbent, and the synthesis conditions were optimized. The ratio of tetraethyl orthosilicate (TEOS) compared to organoclay and dodecylamine (DDA) was selected as a synthesis condition variable (organoclay: dodecylamine: TEOS=1 : 1 : 30–120). We investigated the change of morphology and porosity of PCH by using a transmission electron microscope, nitrogen adsorption/desorption, and x-ray fluorescence. The porosity of PCH was changed depending on the TEOS ratio. As the ratio of TEOS decreased, the pore size of the PCH also decreased. However, irregular layer expansion was observed due to the swelling of organoclay by DDA in PCH30. To evaluate the possibility of using PCH as an adsorbent for low concentration VOCs, specifically toluene and decane, adsorption experiments were conducted, and it was confirmed that micropores play an essential role for low concentration VOC adsorption. PCH60 was selected as an optimal condition. The toluene and decane adsorption capacity of PCH60 was, respectively, measured as 122.92 mg/g and 886.73 mg/g.