Abstract: In order to evaluate the restoration effects of aquatic plants on benzene in polluted water, the cleansing effects on benzene were studied using three hydrophytes, Chara vulgaris L., Nasturtium officinale R.Br. and Potamogeton crispus L., by L₂₇(3¹³) orthogonal design. The results showed that under the experimental conditions, the maximum removal rates of benzene by three hydrophytes reached 35.26%, 69.71% and 55.45%, respectively. Five parameters, i.e. temperature, processing time, biomass, interaction between temperature and time, interaction between temperature and biomass, significantly influenced on removing benzene by C.vulgaris L. The influences of temperature and biomass were significant in removing benzene by N.officinale R.Br. while processing time was significant in removing benzene by P.crispus L. All three hydrophytes could be used as good materials for purifying water. C.vulgaris L. and N.officinale R.Br. may be suitable for use in summer and autumn, meanwhile, P.crispus L. is suitable for use in winter and spring.

Key words: hydrophyte, benzene, cleansing, condition optimization