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This paper discusses propagation measurements and modeling for monitoring and tracking in animal husbandry application

Background: The oil removal from industrial effluents is one of the biggest problems faced in the world. It is a very important environmental issue and it is necessary to solve this problem. In this sense, ZIFs are increasingly important in the environmental area. Objective: This work reports a method for the synthesis of ZIF-zni nanocrystals, at room temperature in 1 h, and a performance of the ZIF-zni nanoadsorbent in the oil removal from oil-water emulsion. Methods: ZIF-zni was produced from the solvothermal method and it was characterized by X-ray diffraction, electron microscopy, contact angle, infrared spectroscopy and thermogravimetry. Oil-water emulsion was produced by lubricant oil and distilled water. Batch-type adsorption at 200 rpm for 2 h was used to evaluate the potential of ZIF-zni for the separation of the oil-water emulsion with initial oil concentration (100, 300 mg/L) and temperature (30, 60 °C). Results: The characterizations showed that the crystalline phase of ZIF-zni was successfully obtained. The ZIF-zni exhibit a very high removal percentage (above 95 %) and adsorption capacity. The predictions of multiple linear regression models determined based on the factorial design of experiments are excellent. Conclusion: The value up to 2879 mg/g of adsorption capacity was reached, thus indicating that the use of the nanoadsorbent ZIF-zni has great potential in the process of separating oil-water emulsion.

Most traditional methods are only used to remove free oil from wastewater, and they are not efficient for separating oil-water emulsions. The adsorption separation process can be widely applied for the treatment of emulsions, mainly due to the cost and benefit of the process and the wide variety of materials that can be used as adsorbents, for example activated carbon, clays, zeolites, etc. Among the various types of porous materials called "Metal Organic Frameworks" (MOFs) are the zeolitic imidazolate (ZIFs) structures. The zeolitic structure of the ZIFs allows to exhibit high surface areas and thus to be promising adsorbents. To evaluate the adsorption capacity of ZIF-8 in the removal of emulsified oil, ZIF-8 was synthesized using Zn metal and as organic binder 2-methylimidazole (Hmim), dissolved in methanol at room temperature. ZIF-8 was characterized by X-ray diffraction (XRD) technique to determine the crystalline structure. To evaluate the capacity of the emulsified oil, a pH-influence test and chemical kinetics were determined. The best pH of the emulsion for removal was pH 6. The chemical kinetics performed at pH 6 presented the best fit with the pseudo-second model with correlation coefficient 0.93. According to the kinetic data, a removal percentage of 92.43% was found with only 30 min of removal.

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