The corrosion inhibition efficiency of p-methoxybenzylidene-4,4′-dimorpholine (p-MBDM) and p-MBDM assembled on nickel oxide nanoparticles (NiONPs) was investigated here.

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A B S T R A C TChitin (CH) and chitosan (CTS) beads used and compared for the adsorption of Congo Red (CR), an anionic azo dye, are reported in the present work. Initially, the adsorbents were prepared and characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) analysis. SEM images showed the heterogeneous and porous structure of the beads and FT-IR results confirm the presence of -OH, -NH 2 , and-NHCOCH 3 groups which are responsible for the adsorption of CR. Further, batch studies were conducted to evaluate the adsorption capacity of CH and CTS beads and the effects of the parameters like pH, adsorbate concentration, contact time, and dosage of adsorbents on adsorption were investigated. From the analysis, it was observed that the amount of CR adsorbed on both the adsorbents increases with increasing initial dye concentration and decreasing pH. The adsorption isotherms were analyzed using the Langmuir and Freundlich isotherms. The Langmuir isotherm was the best-fit adsorption isotherm model for the experimental data obtained from the non-linear chi-square statistic test. Further, the pseudo-first-order and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The dynamical data fit well with the second-order kinetic model. The results indicate that CH and CTS beads could be employed as low-cost material for the adsorption of CR from wastewater.

Adsorption of lead (II) ions onto cassava starch 5-choloromethyl-8-hydroxyquinoline polymer (CSCMQ) was investigated with the variation in the parameters of pH, contact time, lead (II) ions concentration, temperature and the adsorbent dose. The Langmuir and Freundlich models have been applied. CSCMQ was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Results showed that the adsorption process was better described by the Langmuir model. Adsorption kinetics data obtained for the metal ions sorption were investigated using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The maximum adsorption capacities (qm) were 46.512, 43.859 and 42.735 mg/g at 25, 35 and 45 °C, respectively. The dynamical data fit well with the second-order kinetics model. The results indicate that CSCMQ could be employed as low-cost material for the adsorption of Pb(II) ions from aqueous medium.