Furfural, acetic acid, and sulfates are found in the hemicellulose (HMC) fraction of lignocellulosic biomass. Separation of furfural, acetic acid, and sulfates from monosaccharides by four nanofiltration (NF) membranes was evaluated with a model solution of glucose, xylose, furfural, acetic acid, and sulfates. Results showed that Alfa Laval NF99HF is the most promising membrane to purify monosaccharides, with the retentions of xylose (85%), glucose (95%), and with the minimum sulfate retention. pH has the highest impact on the retention of all solutes and there is no significant effect of temperature on the retentions of sulphates and acetic acid. Lower pH and temperature are favored to maximize the monosaccharide retention and to remove acetic acid while retaining more furfural with the monosaccharides. Moreover, fouling tendency is maximized at lower pH and higher temperatures. According to the statistical analysis, the retentions of glucose, xylose, furfural, sulfates, and acetic acid are 95%, 90%, 20%, 88%, and 0%, respectively at pH 3 and 25 °C. The presence of sulfates favors the separation of acetic acid and furfural from monosaccharides.
Bisphenol A (BPA) is a commonly used chemical in consumer products. It is an endocrine disrupter that has potentially significant negative effects on human health. The use and chemical stability of BPA have resulted in the appearance of the chemical in wastewaters. Since the current wastewater treatment technologies are not effective enough to remove BPA, new methods to degrade BPA are required. In this paper, we report the efforts made towards developing a bi-functional catalyst for consecutive catalytic wet air oxidation-photocatalytic water treatment. It was found that 2.5% Pt/Ti0.8Ce0.2O2 is a potential bi-functional catalyst for the consecutive treatment. Concentration and toxicity of BPA were successfully reduced by catalytic wet air oxidation. Although BPA was further reduced by photocatalysis, it was not reflected in further decrease of cell toxicity. Thus wet-air oxidation combined with photocatalysis is a promising approach for the reduction of BPA.