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In this study, the sorption of oil from seawater using chitosan grafted poly(butyl acrylate) copolymer was optimized using response surface methodology (RSM). The effect of various parameters such as time, initial oil concentration, temperature, sorbent dose, and agitation rate on the oil sorption capacity was investigated. Plackett-Burman design was utilized for screening the various sorption parameters. RSM was adopted to acquire the best sorption conditions of two chitosan derivatives namely; CS-g-poly(ButA10) and CS-g-poly(ButA20). In this respect, the Box-Behnken design was applied. A second-order-polynomial model indicated that the sorption was very useful and able to achieve highest sorption capacity ranged from 79.56 to 92.29 g/g using grafted chitosan derivatives compared to 35.2 g/g for native chitosan in 180 min, 41.23-50 g/L of oil concentration, 38°C-41°C at 155-160 rpm. These findings nominate the fabricated CS-g-poly(ButA10) sorbent as an effectual and promising oil sorbent for environmental control of crude heavy oil spills. [ABSTRACT FROM AUTHOR]

Since chitosan and its amino-, cinnamo- or cinnamo-amino- derivatives are acid-soluble, the effect of acetic acid on hyaluronan (HA) macromolecules degraded by Cu(II) ions and ascorbate was examined to produce reactive oxygen species (ROS). Further, the effects of glutathione (GSH), chitosan and its derivatives, added individually or in combination, on the quenching of ROS and ABTS.+ cation radical were examined using rotational viscometry and ABTS assay, respectively. The results of the rotational viscometry indicated a rapid degradation of HA by ROS after the addition of acetic acid. Chitosan and its derivatives moderately decreased the rate of HA degradation, while GSH decreased the rate of HA degradation more significantly. Moreover, GSH enhanced the protection of HA macromolecules against their degradation in the presence of chitosan or its derivatives. The results of the ABTS assay confirmed the results of the rotational viscometry. The GSH in the combination with chitosan and its derivatives reduced ABTS.+ more intensively than when added individually. [ABSTRACT FROM AUTHOR]