Thermal and Catalytic Degradation of Polystyrene with a Novel Catalyst

Waste polymer recycling has received a great attention due to increasing amounts of waste polymers generate enormous environmental problems. The pyrolysis of polystyrene was examined as an effective way to recycle this polymer and recover its monomer styrene. In this paper, thermal and catalytic degradation of polystyrene at the atmospheric pressure was investigated. Various conditions of temperature and catalyst/Polystyrene mass ratio were considered to determine the product composition and effects of catalyst/ Polystyrene mass ratio and temperature on conversion. The results showed that with increasing the temperature, the conversion increased. The products of the degradation mostly consist of liquid, less gas and solid residue. The AIT100s catalyst showed good catalytic performance for the degradation of PS with selectivity to aromatics more than 99%. Keywords Catalytic degradation, polystyrene, monomer, AIT100

Deltamethrin-impregnated bed nets and curtains in an anthroponotic cutaneous leishmaniasis control program in northeastern Iran

<b>Background: </b> Anthroponotic cutaneous leishmaniasis (ACL) has long been a significant public health prob-lem in northeastern Iran. The objective of this study was to determine the efficacy of deltamethrin-impregnated vs. nonimpregnated bed nets (NIBs) and curtains (NICs) in ACL control. <b> Patients: </b> Deltamethrin-impregnated bed nets (IBs) and curtains (ICs) with 25 mg ai/m²were distributed among 160 households in one district and NIBs and NICs were distributed among the same number of households in another district. A third district with a similar numbers of households served as a control. Health education mes-sages were disseminated to ensure the population&#x2032;s complicance with the proper use of bed nets and curtains. Sticky paper traps were used to assess the effect of insecticide-impregnated bed nets and curtains on the density of Phlebotomus sergenti. Deltamethrin susceptibility and also bioassay tests were carried out on the species by WHO standard method. Case findings were done by house-to-house visits once a season and all the inhabitants of the selected households in each district were examined. <b> Results: </b> IBs and ICs provided good protection against sandfly bites and reduced the transmission of ACL in the intervention district, while NIBs and NICs provided no protection. There was no significant difference in monthly density of P. sergenti indoors and outdoors among the districts (P>0.05). This species was susceptible to delta-methrin in the field population in the area. Bioassays confirmed that the nets treated with deltamethrin remained effective for more than 3 months. <b>Conclusion: </b> Personal protection is an effective and sustainable means of preventing and controlling ACL and can reduce dependence on insecticides. We encourage the use of IBs and ICs to control ACL in other high-risk areas of Iran and Afghanistan during the active season of sandflies