Abstract: Rhamnolipid biosurfactant is not only environmentally friendly but also effective in adsorbing on metal oxide surface. However, the hydrophilic property of rhamnolipid tends to decrease its solid-liquid adsorption capacity. Rhamnolipid surfactant can be modified to enhance its hydrophobicity by adding some linker molecules to the solution. Therefore, effects of linker molecules to the adsorption capacity of rhamnolipid biosurfactant on aluminum oxide surface were evaluated. Results showed that the longer carbon chain in linker molecules (1-butanol, 1-octanol and 1-dodecanol) and the higher rhamnolipid adsorption capacity were observed. Surfactant mixed with 1-butanol (4-Carbon atom) showed the lowest rhamnolipid adsorption capacity of 0.10 mmol per gram while the 8-Carbon atom of octanol yielded the highest amount of 0.30 mmol per gram. This result can be attributed to the coiling effect of the linker molecules (1-dodecanol), which hinders the interaction between the head group and the

• Publication Date: 09-Mar-2014
• DOI: 10.15224/978-1-63248-001-9-26
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Abstract: 17α–Methyltestosterone or MT is a synthetic androgenic steroid hormone. It is commonly used in Nile tilapia farming in order to induce the gender of all tilapia fry to be male. MT is also an endocrine disruptor (EDCs) that can disturb the function of the reproductive system of human and animals. Therefore, to prevent the contamination of MT in the environment, wastewater containing MT has to be treated prior to be discharged. In this study, synthetic wastewater containing MT at the initial concentrations of 100, 500 and 1000 ppb was treated by irradiation with UVC lamp at the power of 20 watts. The concentration of MT was monitored using HPLC. For 100 ppb, it was found that MT concentration reduced to less than 5 ppb within 15 minutes of UVC irradiation. The degradation of MT is found to be first order reaction. The degradation rate constant of MT was slightly decreased with the increase of the initial concentration. Degradation mechanism was investigated by adding Tert-butyl alcohol.

• Publication Date: 09-Mar-2014
• DOI: 10.15224/978-1-63248-001-9-27
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