No abstract

Polystyrene (PS) being a non-biodegradable polymer is brought under application over the world in many ways in our day-to-day life to make it easy however it generates an enormous challenge to the components of our environment viz. soil, water, air etc. thus leading to health issues in humans and other living components of earth. This review details and compares the fabrication, application and suitability of various composites of PS with biodegradable materials viz. starch, bagasse lignin, fibers, etc. as to combat the hazardous impact of PS to environment and its valuable constituents. These biodegradable materials not only modify the PS physically but also it affects the composition which enables these composite materials to be acceptable for consumption without spoiling nature. The numerous compositions are studied for their diverse applications and biodegradability. The listed composites express the route to curtail the impacts of hazardous synthetic polymers from the environment and thus paving the path for secure and harmless future for coming generation.

This study focuses on the preparation of HKUST-1@SiO 2 composite and its application as an adsorbent for the removal of chlorpyriphos from water environment. For studying the physical properties, synthesized HKUST-1@SiO 2 was characterized using FTIR, XRD, BET, FE-SEM and EDS. Characterization results indicated that the interaction of HKUST-1 with SiO 2 resulted in improvement of various physicochemical properties. The integration of HKUST-1 and SiO 2 resulted in improved adsorption of chlorpyrifos, where maximum 85 % removal was obtained at 30 °C. The adsorption data was best fitted into Langmuir isotherms, and it was in well accordance with pseudo second order kinetic model. High adsorption efficiency of the composite is related to its high pore volume which results in high number of adsorption sites on silica surface for the attachment of various functional groups present in chlorpyriphos.

Electrical conductivity data is presented for two types of polypyrrole film prepared using toluene sulphonate and sulphate as the counter-ions or dopant. The films based on polypyrrole and toluene sulphonate exhibit an ordered molecular organisation in which the planes of the aromatic units lie preferentially parallel to the film surface. For such films the conductivity versus temperature data fit to a 2D variable range hopping model. In contrast, films using SO42- as the dopant show an isotropic highly disordered molecular organisation and a temperature dependence of the electrical conductivity which fits a 3D variable range hopping model. Although such models present a rather simple picture of conductivity in these complex molecular composites, they do demonstrate the strong and direct influence of the molecular organisation on their electrical transport properties.