Iodine number (IN) is the way to know the micro-pore content of surface. The iodine molecule is relatively small with an area of 0.4 nm2 and can enter in the smaller micro pores (Alaya et el., 2000; Baçaoui et el., 2001). The iodine number can use for approach determination of surface area and microporosity (? 2 nm) of the sorbent (Nunes and Guerreiro, 2011; Saka, 2012). The iodine number of SVTPUP@ZnONPs is 3.62 mmol/g (459.05 mg/g). The specific surface area of SVTPUP@ZnONPs was also estimated using iodine number (S=(IN×N×A)?M) (Wu, 2007; Mianowski, 2007) where S is the area occupied by adsorbed iodine molecules at the maximum mono-layer surface coverage (m2/g), N is the Avogadro number (6.02 ×1023), A is the iodine surface area (0.2096 ×10?18 m2) and M is the iodine molar mass (126.92 g/mol). So, the specific surface area obtained is 456.4 m2/g. The BET surface area of SVTPUP@ZnONPs is very small compared with calculated surface area by iodine number method. It indicates that the iodine number method is incorrect for determination of SVTPUP@ZnONPs surface area (Tran, 2017). Thus it can be concluded that the adsorption process of iodine molecules occurred not only by the pores of the surface of SVTPUP@ZnONPs but also through its functional groups e.g. ether groups.