بررسي رفتار جهت‌گيري خرچنگ منزوي Diogenes avarus تحت تاثير بوي غذا و بوي شكارچي

Adsorption of Cadmium from aqueous solution by the dead algae biomass Scenedesmus sp.: Isotherm, kinetics and thermodynamics studies

هدف از اين تحقيق بررسي رفتار جهت‌گيري خرچنگ‌هاي منزوي Diogenes avarus تحت تأثير نشانه‌هاي شيميايي غذا و دشمنان بود؛ بنابراين، رفتار جهت‌گيري نمونه‌هاي D. avarus به‌سوي هدف در حضور آب دريا حاوي نشانه‌هاي شيميايي در غلظت‌هاي 1، 2 و 4 گرم بر ليتر در 24 ساعت بوي مواد دفعي شكارچي و 1، 2 و 3 گرم بر ليتر در 24 ساعت بوي غذا در محيط دايره‌اي موردمطالعه قرار گرفت. نتايج نشان داد كه نمونه‌ها در گروه شاهد داراي جهت‌گيري يكنواخت بودند P<0/05 تيمارهاي حاوي بوي شكارچي، جهت‌گيري غيريكنواخت معناداري را به سمت مخالف هدف نشان دادند (P<0/05. در تيمارهاي حاوي بوي غذا، با افزايش بوي غذا جهت‌گيري به سمت هدف نيز به‌صورت معناداري افزايش يافت (P<0/05. نمونه‌هاي D. avarus بر پايه‌ي برهمكنش بين اطلاعات بينايي و شيميايي موجود در محيط، به محرك‌هاي محيطي پاسخ‌ رفتاري مناسب ميدهند.

Heavy metal pollution has become one of the most serious environmental problems today. Biosorption is usage of biomaterials such as bacteria, fungi, yeast and algae that is regarded as a cost-effective biotechnology for the treatment waste containing heavy metals. This study was conducted in order to evaluate the application of non-living biomass of Scenedesmus sp. algae as biosorbent in eliminating cadmium from synthetic wastewater. In the batch system amount of cadmium absorbed affected by the parameters of concentration, pH, temperature and contact time, were studied in laboratory. The concentration of Cadmium was determined by Atomic absorption spectrometry. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the pseudo- first -order and Pseudo- second- order synthetics and thermodynamic equation of absorption. It was found that optimal adsorption (a removal of 98.71 percent) obtained at adsorbent amount of 0.1gr, concentration 40mg/L, pH = 5, temperature 20°C and equilibrium time of 45min. At reviews the correlation coefficient, adsorption kinetics follows the pseudo-second-order model and equilibrium is well described by Freundlich isotherm. According to adsorption thermodynamics, the reaction found to be spontaneous, exothermic and non-random. FTIR spectrum revealed that functional groups C = O, -OH and -NH that they played a major role in the adsorption. The high efficiency (98.71%) of the adsorption process in this study showed that Scenedesmus sp. algae have a good capability in eliminating cadmium and it can be used method for eliminating cadmium from wastewater.