Oil sorbency of sorbents prepared from kenaf (Hibiscus cannabinus L.) plants

Abstract

Kenaf plants, which are annuals, grow rapidly, and have recently been spotlighted as new materials for paper making that will replace wood pulps from an environmental viewpoint. In order to enlarge the application of kenaf plants, oil sorbents were prepared from three kinds of kenaf (Qingpi No.3, Zhejiang No.1 and Everglades 41) which were cultivated in Fukuoka (latitude: 33°35' N, longitude 130°23' E, altitude: 2.5m) in 1998, and their sorbency of waste food oil was investigated. With regard to the defibrated fibers and holocellulose sorbents of kenaf and heated kenaf, the oil sorbency (12-33g/g) of the sorbents from kenaf bast fibers was greater than that (8-30g/g) of the sorbents from kenaf core fibers and the order of oil sorbency was Qingpi No.3 > Everglades 41 > Zhejiang No.1. The most efficient oil sorbents prepared from the kenaf plants in this study were the defibrated kenaf bast and core fibers heated at 300 - 350°C for 5 minutes on the ground with yields of 95-78% and 95-62%, respectively, and about a 25 g/g oil sorbency, respectively. Furthermore, their oil sorbency and yield were greater than those (20g/g, 40-55%) of commercial sorbents made of cellulose pulps obtained from wood. The changes in the specific surface area and the functional groups of the heated kenaf, derived from the partial pyrolysis of the hemicellulose and cellulose of the kenaf fibers, were assumed to have contributed to their capacity to sorb waste food oil.