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In the present study, the hydroxyl terminated triazine-based dendritic polymer was synthesized and grown on the halloysite nanotubes surface (HNT-G2) to efficiently remove the Cd (II) ions from aqueous solution. The nanoadsorbent morphology and structure were determined through transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analyzer, Brunauer-Emmett-Teller isotherm, and energy dispersive X-ray spectroscopy analysis methods. The adsorption of Cd (II) has resulted a maximum of 105.26 mg g À1 at 298 K at optimal pH 6. As research revealed the adsorption kinetic followed the pseudo-second-order model, while the adsorption isotherms corresponded the Langmuir model. Accordingly, it could be inferred that the Cd (II) was a single-layer adsorption occurring on the adsorbent surface, and further, the rate-controlling step was denoted chemical adsorption. Also, the thermodynamic results showed that the adsorption process could occur spontaneously; therefore, it was considered as an endothermic reaction. Surprisingly, the adsorption and desorption efficiency after four cycles was high, while the Cd (II) adsorption mechanism affecting the adsorbent was basically via chelation through the O atoms. Hence, it can be concluded that the HNT-G2 was effective in efficiently removing of Cd (II) from the aqueous solution, having high applicability significance.

Background: Controlling and validating the environmental performance of organizations, is a major problem that has been stated in the international standard ISO 14031. The aim of this study was to present a model for evaluating the environmental performance of Iran’s gas refineries using the environmental performance evaluation (EPE) method, based on the operational performance index (OPI) and management performance index (MPI). This case study was conducted in the ninth refinery of the South Pars Gas Complex (SPGC), Bushehr province, Iran, during 2019-2020. Methods: The research method comprises two stages. The first stage was distinguishing the standards and markers of the MPI and OPI using the Fluffy Delphi strategy and the second one was focusing on and relegating loads to the measures and pointers using the logical analytical hierarchy process (AHP) prior to confirming the outcomes by applying the TOPSIS. Results: The total normal scores of the total OPIt and OPTt were obtained to be 2.3409 and 2.2647, respectively. Considering these coefficients, the organization is balanced in terms of the environmental performance. The implementation steps of the TOPSIS method in the ninth refinery (A1 ) with the first (A2 ), second (A3 ), and third (A4 ) refineries, which had the same extraction indices of OPIt and MPIt, were ranked as A1 > A3 > A4 > A2 , respectively. Conclusion: Petrochemical industries have the potential to cause adverse effects on the environment due to the nature of activities and effluents production, emissions, and hazardous wastes. However, they can increase their weight to be more competitive and reach the ranks of mature organizations by planning on important indices.

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