Adsorption Of Pollutants In Water By Modified Pencil Lead

Along with the global development,environmental pollution has become a hot issue and a serious threat to the health of human beings.There is no room to delay the prevention and control of environmental pollution.There are some well-established protocols to prevent and control environmental pollution including solid-substrate adsorbents.The commonly used adsorbents are natural minerals and carbonaceous materials which are not satisfying,and carbonaceous materials need specific treatments which are both time-consuming and labor-extensive.Therefore,the development of a new material for pollute adsorption has become an emerging research field.Pencil leads have become a new substrate for absorption because of its low price,controllable carbon content,quantifiable production and simplicity in processing.Pencil leads consisting of both clay and graphite have been demonstrated to be good absorbers.In this dissertation,HB and 2B pencil leads were chemically modified and were used for the adsorption of soluble organic dyes and bisphenols.After optimization of experiments,the following conclusions were obtained by using high performance liquid chromatography(HPLC):(1)Modified pencil leads have adsorption effects to bisphenol A,bisphenol B,bisphenol F,bisphenol AF and bisphenol S.Different modification methods would lead to different adsorption performance.Among all modified pencil leads,the greatest adsorption rate to bisphenol A at 48.92% with a standard recovery rate ranging from 87.88% to 119.34%.The maximum adsorption rate of bisphenol B was achieved by using 2B acid treated pencil leads at 69.61% with a standard recovery rate of 84.59%~117.88%.The maximum adsorption rate of bisphenol F was achieved by using acid treated 2B pencil leads at 42.54% with a standard recovery rate of 80.09%~91.10%.The maximum adsorption rate of bisphenol S was achieved by using acid treated 2B pencil leads at 35.88% with a standard recovery rate of 86.70%~119.99%.The maximum adsorption rate of bisphenol AF was achieved by using acid treated 2B pencil leads at 80.99% with a standard recovery rate of 93.22%~97.19%.(2)Modified pencil leads also shown adsorption effect to rhodamine B,methylene blue,brilliant green and eosin Y.Different modification methods would lead to different adsorption performance.For rhodamine B,water treated 2B pencil leads has the best adsorption effect with a maximum adsorption rate at 59.81% and a standard recovery rate of 95.58%~108.95%.For methylene blue,water treated 2B pencil leads has the best adsorption effect with a maximum adsorption rate at 74.15% and a standard recovery rate of 110.33%~119.42%.For brilliant green,water treated 2B pencil leads has the best adsorption effect with a maximum adsorption rate at 74.15% and a standard recovery rate of 99.48%~106.78%.For eosin Y,acid treated HB and acid treated 2B pencil leads have the best adsorption effect with a maximum adsorption rate at 100% and a standard recovery rate of 90.21%~102.96%.