N¹,N¹-diallyl-N⁶,N⁶,N⁶-tripropylhexane-1,6-diaminium chloride (NDTHDC) and its polymer poly(N¹,N¹-diallyl-N⁶,N⁶,N⁶-tripropylhexane-1,6-diaminium chloride) (poly-NDTHDC) were synthesized and tested against API X60 carbon steel corrosion in 15 wt % HCl solution. Weight loss, electrochemical, and surface analysis techniques were used. Results show that poly-NDTHDC is better than NDTHDC. Moreover, 1000 mg/L NDTHDC protected the studied surface by 79.1% at 25 °C, while 100 mg/L poly-NDTHDC afforded 86.1% protection. Inhibition efficiency increases with temperature (up to 60 °C) but depreciates thereafter. NDTHDC and poly-NDTHDC perform better under the hydrodynamic condition than the static condition. TGA and FTIR results reveal that poly-NDTHDC is chemically and thermally stable.

In this work, a unique cross-linked polyzwitterion/anion with an aspartic acid residue was synthesized via butler's cyclopolymerization protocol involving N,N-diallylaspartic acid hydrochloride, 1,1,4,4-tetraallylpiperazinium dichloride and sulfur dioxide in the presence of azoisobutyronitrile. The structure and morphology of the polymer were characterized by using FTIR, TGA, EDX and SEM. The adsorption performance of the resin was evaluated using lead Pb(II) as a model. The effect of various parameters such as contact time, pH, initial concentration and temperature were investigated to arrive at optimum conditions. An optimum pH of 6.0 and dosage of 1.5 g L⁻¹ were obtained. The mechanism of adsorption was investigated using kinetic, diffusion, isotherm and thermodynamic models. The adsorption kinetic data were described well by the pseudo-second order model with R² of 0.999. The activation energy (E_a) of the adsorption process was calculated as 39.29 kJ mol⁻¹. The negative ΔG^o values indicate a spontaneous adsorption process while the negative ΔH^o (−43.87 kJ mol⁻¹) suggests an exothermic reaction. Adsorption data were described well by the Langmuir and Temkin models. EDX analysis confirmed the adsorption of Pb²⁺ on the polymer. The overall results suggest that the polymer could be employed as an efficient adsorbent for the adsorption of toxic Pb²⁺ from polluted aqueous solutions.