Papers by Author: J.F. Scamehorn

Abstract: The removal of arsenic from synthetic arsenic contaminated water sample by precipitating arsenic (in the form of arsenate oxyanion) with calcium phosphate hydroxyapatite, HAp, was studied under conditions that induce arsenate incorporated calcium phosphate hydroxyapatite, Ca (P/As)HAp, to form. Arsenate is able to substitute for a fraction of the phosphate in HAp host material as it forms. Consequently, arsenic is successfully removed from the contaminated water achieving up to 99% arsenic removal from 25 ppm initial arsenic concentration. The Ca:(P+As) and P:As mole ratios were found to play an important role in arsenic removal efficiency. Higher Ca:(P+As) and P:As mole ratios give higher arsenic removal efficiency. Surprisingly, the pH of the initial anion solution, a key parameter in arsenic speciation, was found to not have a significant effect on arsenic removal by this process. The advantage of this process is that the precipitation can occur rapidly at relatively low levels of arsenic contamination, implying an easy and inexpensive process for arsenic removal can be developed based on this approach.

Abstract: Detergency process of oily soil removal from fabrics is of interest and the mechanisms of oily soil removal are very complicated involving several factors: interfacial tension, oil loading and surfactant adsorption. In this study, the effects of oil loading and the surfactant adsorption on the detergency performance of oily soil removal were investigated. Mixed surfactant systems of branched alcohol propoxylate sulfate sodium salt (Alfoterra 145-3PO), an extended anionic surfactant, and secondary alcohol ethoxylate (Tergitol 15-S-5), a nonionic surfactant, were used to form microemulsions with motor oil. The CMC and CµC values of the mixed surfactants were 0.015 and 0.04 % total active mixed surfactants concentration, respectively. A polyester/cotton blend [65/35] was selected to use as a testing fabric in detergency experiments. The results showed that the oil loading and fabric weight did not affect the efficiency of oil removal. Furthermore, with the selected formulation (0.1 wt.% Alfoterra 145-3PO and 5 wt.% Tergitol 15-S-5), the oil detachment time was investigated at different temperatures (30-50°C) and different total surfactant concentrations (0.04-0.5 %). The results showed that increasing temperature and surfactant concentration were found to decrease the oil detachment time, leading to increasing oil removal.