Extraction, characterization, and biosurfactant properties of extracellular polymeric substance from textile wastewater activated sludge.

Textile wastewater treatment generates sludge that needs to be disposed of safely. The cost of sludge management is 50% of the total treatment cost of the wastewater. To reduce the expense, the sludge can be repurposed as a valuable resource by extracting extracellular polymeric substance (EPS). EPS contains polysaccharides, proteins, and humic substances, which are surface-active substances that act as potential biosurfactants. In this study, we investigated sludges (sludge 1 and sludge 2) from two different textile industries for EPS production. The results showed a maximum EPS yield of 179 mg/g-activated sludge from the wastewater from sludge 2. The EPS from textile wastewater activated sludge had a protein/carbohydrate ratio of 0.27-0.56, lower than that of municipal activated sludge. This difference is due to variations in nitrogen/carbon ratio in these wastewaters. Based on the biosurfactant activity test, EPS from both textile wastewaters could lower the water surface tension to around 60 mN/m and emulsify olive oil better than Tween 20 and 80. However, only EPS from sludge 2 showed better xylene emulsification than EPS from sludge 1 due to the difference in humic acid content.

The removal of 3-monochloropropane-1,2-diol ester and glycidyl ester from refined-bleached and deodorized palm oil using activated carbon.

Palm oil has fulfilled most of the oil needs in the food sector in the world. However, palm oil is indicated to contain small amounts of compounds that are harmful to humans, especially to infants. These toxic contaminants are 3-monochloropropanediol (3-MCPD) esters and glycidyl esters (GE), which are formed during the deodorization of palm oil at high temperatures. This study aims to reduce the 3-MCPD ester concentration in refined, bleached, and deodorized palm oil (RBDPO) through adsorption using activated carbon. The activated carbons were treated with heat and acid-washing using HCl at various concentrations and were characterized. The treatment altered the physicochemical characteristics of the activated carbon (surface area, pore volume, pHPZC, and CEC), resulting in the enhancement of its adsorption characteristics (adsorption capacity). The activated carbon treated with 2 N HCl (AC 2 N) was chosen as the proper adsorbent, due to better surface area, better pore volume, highest CEC value, and better positive charge in RBDPO. The 3-MCPD and GE adsorption capacity of AC 2 N was 1.48 mg g-1 and 29.68 mg g-1, respectively. The adsorption ability of pretreated activated carbon towards 3-MCPD esters was examined in a batch system at various adsorption temperatures. The 3-MCPD ester concentration in RBDPO was successfully reduced by up to 80% at 35 °C using the activated carbon treated with 2 N HCl solution. On the other hand, the activated carbon was able to reduce the other contaminant of GE in RBDPO up to 97% from the initial concentration of GE.