Sonolysis

Abstrak Carbaryl rmerupakan insektisida untuk mengendalikan hama pada tanaman seperti jagung, kacang tanah, kapas, kedelai, kelapa, kelapa sawit, kopi, lada, tebu, teh dan tembakau. Carbaryl dijual sebagai pencampur dalam beberapa merk dagang, salah satunya Sevin 85 S. Pada penelitian ini, dilakukan dekomposisi carbaryl secara sonolisis dengan menggunakan gelombang ultrasonik dan ozonolisis dengan menggunakan ozon (O3) selanjutnya dilakukan penggabungan kedua metoda ini (sonolisis dan ozonolisis) yang dinamakan sonozolisis. Hasil penelitian menunjukkan degradasi carbaryl 20 mg/L secara sonolisis tanpa penambahan TiO2-anatase selama 150 menit pada suhu 45 o C mencapai persen degradasi 12,66%, sedangkan penambahan TiO2-anatase mencapai persen degradasi 36,68%. Dengan menggunakan metoda ozonolisis, degradasi carbaryl 20 mg/L selama 90 menit mencapai persen degradasi 48,00%, dan secara sonozolisis, senyawa carbaryl terdegradasi mencapai 67, 28% selama 75 menit.

Fenton Process, a type of Advanced Oxidation Processes is an efficient method for treating textile wastewaters. However, excessive use of hydrogen peroxide and catalyst has made this process economically non-feasible. Besides, industrial grade hydrogen peroxide costs $390-500 per ton. One of the means to overcome this problem is the in-situ production of hydrogen peroxide. In this paper, a detailed review was conducted on the generation methods, degradation potential and optimum operating parameters for in-situ production of hydrogen peroxide/hydroxyl radicals. Additionally the scavenging aspect for hydroxyl radicals was also investigated. From this review, it can be concluded that hydroxyl radical is highly oxidative and non selective in nature and its in-situ production can be performed through application of catalyst, ozonation, photocatalysis, electro and microbial fuel cells. Furthermore, optimization of operating parameters can result in an increase in the yield of hydroxyl radicals/hydrogen peroxide. Sonolysis as an auxiliary tool has potential to induce synergetic effects in combination with Advanced Oxidation Processes to increase in-situ hydrogen peroxide production. However, the problem of the scavenging effect is an aspect that needs to be dealt with, as hydroxyl radicals are prone to deactivation by scavengers. Therefore based on the review, it is concluded that insitu production of hydrogen peroxide/hydroxyl radical for treating textile wastewater is economically viable and practically feasible if careful selection of process is conducted through selective research. (C) 2014 Elsevier Ltd. All rights reserved.

http://www.sciencedirect.com/science/article/pii/S0959652614009408

Removal of 2-chlorophenol by ultrasonic waves (sonolysis), inorganic catalyst, and a combination of the two processes was tested and compared with each technique. In sonolysis, 2-chlorophenol mostly degraded indirectly in the bulk of solution by the radicals produced in the cavitation process. In catalyst treatment, the removal was performed in the presence of Al2O3, TiO2 and CuO. The highest removal was achieved in the presence of TiO2 for this pollutant. In the combined method an enhancement was observed for the removal of 2-chlorophenol. This could be attributed primarily to the continuous cleaning and chemical activation of the catalyst by acoustic cavitation. The mass transfer between the liquid phase and the catalyst and also the surface area of the catalyst are accelerated by the ultrasonic waves. The removal of 2-chlorophenol was performed under different intensities of irradiation, temperatures and quantities of catalyst. Some experiments were conducted in the presence of a...

This study presents sonoassisted microbial reduction of hexavalent chromium (Cr(VI)) using Bacillus sp. isolated from tannery effluent contaminated site. The experiments were carried out with free cells in the presence and absence of ultrasound. The optimum pH and temperature for the reduction of Cr(VI) by Bacillus sp. were found to be 7.0 and 37 °C, respectively. The Cr(VI) reduction was significantly influenced by the electron donors and among the various electron donors studied, glucose offered maximum reduction. The ultrasound-irradiated reduction of Cr(VI) with Bacillus sp. showed efficient Cr(VI) reduction. The percent reduction was found to increase with an increase in biomass concentration and decrease with an increase in initial concentration. The changes in the functional groups of Bacillus sp., before and after chromium reduction were observed with FTIR spectra. Microbial growth was described with Monod and Andrews model and best fit was observed with Andrews model.