Preparation And Application Of Modified Oiltea Camellia Shell Biochar

Oiltea camellia shell is a common agricultural waste with large yield in southern China,but it?s deficient in effective methods for renew resource.Therefore,in response to these problems,the sodium hydroxide ethanol solution and sodium silicate solution is used to modify oiltea camellia shell biochar to prepare composite materials,and research on strengthening biochar?s removal efficiency of cadmium,lead and corresponding mechanism are carried out.Its aims to provide scientific support and data accumulation for the resource utilization of camellia oleracea shells.(1)Study on single and compound adsorption of Cd and Pb by sodium hydroxide modified oiltea camellia shell-derived biochar.Biochars were pyrolyzation after oiltea camellia shell was immerse in sodium hydroxide system solution,and named sodium hydroxide alcohol solution modified-biochar(EBC),Sodium hydroxide aqueous solution modified-biochar(SBC),pristine biochar(BC),respectively.Biochar was characterized by SEM,BET,FTIR and XPS,and results showed that the specific surface areas of EBC,SBC and BC were 28.82 m~2/g,19.14 m~2/g and 10.34 m~2/g,respectively.Obviously,sodium hydroxide system could increase specific surface area of biochar.The FTIR and XPS results showed that EBC has a large number of C=C and oxygen-containing functional groups,SBC has more oxygen-containing functional groups than BC,and adsorption capacities of EBC,SBC and BC to Cd and Pb were successively reduced.In the unary system,the maximum adsorption capacities of EBC and SBC to Cd were2.90 and 1.53 times of BC,and the maximum adsorption capacities of EBC and SBC to Pb were 8.43 and 5.41 times of BC,respectively.In the binary system,the maximum adsorption capacities of EBC and SBC to Cd were 12.28 and 9.60 times than BC,and the maximum adsorption capacities of EBC and SBC to Pb were 2.90and 2.32 times than BC,respectively.(2)Study on Cd adsorption and soil culture by sodium silicate modified oiltea camellia shell-derived biochar.The results of FTIR and XPS shown that Si was loaded on sodium silicate modified biochar surface successfully,and Si mainly exists in the form of Si-O and C-Si.The adsorption experiment results showed that Cd adsorption capacity of the four biochars(Biochar-high Si,Biochar-mid Si,Biochar-low Si,Biochar)were decreased,respectively.As p H～7.0,the saturated adsorption capacity of Biochar-high Si,Biochar-mid Si,Biochar-low Si for Cd was 3.40,2.61,1.93 times to Biochar,respectively.XPS analysis shows that the adsorption mechanism of Cd adsorption by modified biochar maybe cause by C-Si-O-Cd and Cd-Complex.The results of the 90 days soil incubation experiment showed:after modified biochar addition,and the incubation time of 60 days,the soil p H value increased slowly after addition of biochar,and acid soluble Cd decreased gradually,and residue Cd increased gradually.Compared with CK,soil p H value in the MBC experiments with 5.0%addition significantly increased,acid soluble Cd significantly decreased,and residue state?s trend was reversed.