Vol.:(0123456789) 1 3 Iranian Polymer Journal https://doi.org/10.1007/s13726-020-00861-1 ORIGINAL RESEARCH Efciency of polyurethane elastomer containing sulfonated groups as chain extender in removing Malachite green Fatemeh Mojerlou 1  · Mehdi Barikani 2  · Moslem Mansour Lakouraj 1  · Vahid Hasantabar 1 Received: 28 January 2020 / Accepted: 1 September 2020 © Iran Polymer and Petrochemical Institute 2020 Abstract A novel type of polyurethane elastomer (PUE) containing nanocomposites of sodium alginate thiacalix[4]arene macrocy- cles including sodium alginate-thiacalix[4]arene and sodium alginate-tetra-sulfonated thaiacalix[4]arene (SA-TSTCA) was prepared. The key role of these nanocomposites merged into polyurethane elastomers is to function as chain extenders. To provide profound insight into the structural, thermal, mechanical, morphological and hydrophilic properties of the samples, several techniques were employed, namely Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy (SEM) and diferential scanning calorimetry (DSC). Also the results were compared with the results of polyurethane elastomer based on glycerol (Gly) as chain extender. The results showed that the samples extended with nanocomposites as chain extender have better thermal and mechanical properties and between them the PUE containing SA-TSTCA showed higher thermal and mechanical properties. Furthermore, these elastomers have been used as adsorbent for removal of Malachite green (MG) for investigation of the efect of sulfonated groups introduced on the chain extender. The results revealed that SA-TSTCA-based polyurethane elastomer nanocomposite could well adsorb Malachite green from aqueous media by a batch adsorption method. The pseudo-frst-order and pseudo-second-order kinetic models were employed to provide an in-depth study of the adsorption capacity of MG, suggesting that its adsorption onto PUE/SA-TSTCA elastomer was in accordance with pseudo-second-order kinetic process. A possible mechanism of adsorption was suggested where π–π stacking interactions, H-bonding interaction and electrostatic attraction controlled the MG adsorption. Keywords Polyurethane elastomers · Dye removal · Sodium alginate · Thiacalix[4]arenes · Malachite green Introduction Due to ever-increasing rate of industrial pollution, the amount of heavy metal ions and dyes released in the environ- ment is highly induced [1]. Dye pollution is harmful for len- tic life and living organisms even if the dye contact is short. Several industries such as food, textile, paper, printing, cosmetics, dyestuf, leather, pigments and medical indus- tries usually use dyes as their daily products, by-products or reagents adding risk to the concern of poisoning the water resources.MG is well applied in dying some materials such as cotton, silk, leather, paper and it is being used in textile industry. Figure 1a shows the molecular structure of this triphenylmethane cationic dye [1–3]. MG is also utilized as a pesticide in aquaculture. Moreover, it is used as a biological risking factor for microscopic analysis. It can be very much harmful to the human body showing intensive impact on the immune and fertility systems. It can also be a carcinogenic, genotoxic, teratogenic and mutagenic agent which are det- rimental for human health [4]. Therefore, some immediate actions were required for their elimination [2]. Adsorption is a simple separation method in which either natural, mineral or organic adsorbents can be used [5]. Dif- ferent materials containing zeolites, activated carbon, agro- nomical wastes, biomass, clays and synthetic polymers have been utilized as adsorbents [6–8]. Many of these are not considered as ideals due mainly to their high expenses, small thermal stability, little mechanical strength and negligible sorption efciency. Biopolymers with their vast diversity are capable to linking to diferent kinds of ions or molecules * Mehdi Barikani M.Barikani@ippi.ac.ir 1 Department of Polymer Chemistry, University of Mazandaran, 47416 Babolsar, Iran 2 Department of Polyurethane and Advanced Materials, Faculty of Science, Iran Polymer and Petrochemical Institute, 14965-115 Tehran, Iran