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Green recycling of poly(ethylene terephthalate) plastic waste, in this respect, PET waste was subjected to de polymerization process with tri methylene glycol (1,3-propandiol) in the presence of manganese acetate (1.0 % w/w to the total Wight of the reactants) as trans esterification catalyst, the product is Bis-(3-hydroxy-propyl)-terephthalate, BHPT, as a non-ionic surfactant was separated and characterized by FT-IR and 1 HNMR and evaluated as corrosion inhibitor for carbon steel alloy in artificial marine environment using chemical and electrochemical techniques. Effect of inhibitor concentrations and reaction temperature were studied. The chemical techniques used in this work are gravimetric, thermometric and atomic absorption spectroscopy(AAS), whereas the electrochemical techniques are open circuit potential, potentiodynamic polarization. The corrosion inhibition efficiency increases with increasing inhibitor concentrations and decreased by rising temperature. The maximum corrosion inhibition efficiency 96.5% was afforded using 300 ppm of the used inhibitor derived from plastic waste. Potentiodynamic polarization curves indicate that the used system act as mixed inhibitor. The data of AAS show that the iron(iii) ions Fe +3 concentrations were decreased by increasing inhibitor concentration. All the used techniques are in good agreement to each other (±2 %) and shows that the used drug acts as green corrosion inhibitors for steel in marine environment.

Biopolymers and nanomaterials are ideal candidates for environmental remediation and heavy metal removal. As hexavalent chromium (Cr6+) is a hazardous toxic pollutant of water, this study innovatively aimed to synthesize nanopolymer composites and load them with phycosynthesized Fe nanoparticles for the full Cr6+ removal from aqueous solutions. The extraction of chitosan (Cht) from prawn shells and alginate (Alg) from brown seaweed (Sargassum linifolium) was achieved with standard characteristics. The tow biopolymers were combined and cross-linked (via microemulsion protocol) to generate nanoparticles from their composites (Cht/Alg NPs), which had a mean diameter of 311.2 nm and were negatively charged (−23.2 mV). The phycosynthesis of iron nanoparticles (Fe-NPs) was additionally attained using S. linifolium extract (SE), and the Fe-NPs had semispherical shapes with a 21.4 nm mean diameter. The conjugation of Cht/Alg NPs with SE-phycosynthesized Fe-NPs resulted in homogenous distribution and stabilization of metal NPs within the polymer nanocomposites. Both nanocomposites exhibited high efficiency as adsorbents for Cr6+ at diverse conditions (e.g., pH, adsorbent dose, contact time and initial ion concentration) using batch adsorption evaluation; the most effectual conditions for adsorption were a pH value of 5.0, adsorbent dose of 4 g/L, contact time of 210 min and initial Cr6+ concentration of 75 ppm. These factors could result in full removal of Cr6+ from batch experiments. The composited nanopolymers (Cht/Alg NPs) incorporated with SE-phycosynthesized Fe-NPs are strongly recommended for complete removal of Cr6+ from aqueous environments.

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The performance of Copper Sulfide (CuS) was evaluated as sorbent material for Permanganate ions ( MnO 4 − ). The influences of pH, MnO 4 − concentration, sorption time and temperature were inspected. The outcomes of this study approved that the sorbate primary concentration of 1200 mg l−1, solution pH of 1.5, 90 min sorption time and temperature of 60 °C are the optimal conditions for MnO 4 − sorption by CuS. The study also revealed that the kinetic model of second order and model of Langmuir isotherm describe well the experimental data of this sorption. Furthermore, significant sorption capacities of 769.23, 909.09, 1111.11 and 1250.00 mg g−1 were resulted at 20 °C, 30 °C, 40 °C and 60 °C, one-to-one. Additionally, thermodynamic outcomes confirmed that the nature of MnO 4 − sorption by CuS is a heat-absorbing and spontaneous.