Following theindustrialization of societies andthe incidenceofinfectionassociated withthe environment, fromthe second halfof the twentiethcentury,attentiontothe environmentandtheharmfuleffectsthatmay resultfrompolluting has been.Soil as part of the environment is special habitat for in land creatures like humans and plants. Petroleum-contaminatedsoilsforagricultural, residentialandentertainment use not suitable and removalof this compound is necessary and communitiesneedsuitable methods forthisimportantmatter. Among thebiologicalmethods, the useofplantstoreducepollutioninthe so-called phytoremediationitmuch attentionhas been paid.Recently,in order tobetter successinphytoremediation ofoilandreducethese compoundsin thesoil, the suitable combinationofstrategiesis used. Amongthese strategies,the useof additivesis that can reduce cost andtime requiredfor remediation ofcontaminantsas possible.Theaimof this studywas investigation of effect ofcarbon nanotubesasan additive toplantmediumon plant growth in contaminated environments. Therefore, pretreated and treated seedlings with carbon nanotubes solution in 0, 10, 20 and 40 mg/l concentration were planted in soils by three pollution level (4.16%, 2.76%, 2.43%) and harvested after 12 weeks and finally, samples were taken from threeroot zone. The results showedthatpollution increasing reducedyield of each plant or its dry matter from 2.2352 gr to 0.7952 gr. Also multiwalledcarbon nanotubes affected important palnt parameters such as plantdryweight, plant heightandleafchlorophyll aspretreatment 10mg/ lCNThadthe highestyieldamongtreatments (2.0655 gr) and pretreatment 40 mg/l and treatment 40 mg/l caused the highest chlorophyll content (6.6267 and 6.4519 respectively). At theminimum and maximum contaminationlevel ofthesoilpollutant, removal of contamination was less than soil 2 (containing 2.76% TPH). Carbon nanotubes had different effects on pollutant removal from soil such that pretreatments remove contaminants from soil however CNT treatments caused pollutants accumulation in soil. By comparing theeffect of root zone onpollutant removalit was observed whatever distance from plant root is more then pollutant removal will be less. Generally results of thisstudy indicatedthatthe useofmaterials such ascarbon nanotubeson thephytoremediationcanbe effective, but further studiesareneeded in this field. Keywords :Petroleum hydrocarbon, Phytoremediation, Multiwalled carbon nanotubes and Pollutant removal
