Study On The Preparation And Adsorption Properties Of Grape Vine Biochar

At present,the situation of heavy metal pollution in China is becoming more and more serious.Every year,the country has suffered a lot of economic losses that caused by the reduction of grain due to the heavy metal pollution.Research and development of environment-friendly materials with low cost and high efficiency to deal with the issue of heavy metal pollution has always been a trending topic.Biochar is a kind of highly aromatic and carbon-rich solid material produced by pyrolysis and carbonization of biomass materials under anaerobic or hypoxic conditions.It has great potential for heavy metal pollution remediation due to its low specific gravity,high pH value,rich surface active functional groups,low treatment cost,wide sources and long-term stability.However,it is still unclear how the biochar materials prepared at different temperatures affect the adsorption capacity of different heavy metals;the relationship between the adsorption capacity and the composition and structure of the biochar has not been studied in depth.Therefore,grape vine was used as biomass material to produce biochar by pyrolysis at 300⁶00 ? and nitrogen atmosphere.The properties of grape vine biochar were characterized and physicochemical analyzed by x-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscope and Brunauer-Emmett-Teller.The performance and mechanism of grape vine biochar adsorbing cadmium and lead ions were emphatically studied,and the effects of biochar on two kinds of weight at different pyrolysis temperatures were explored.In the process of metal ion adsorption,it was found that minerals and compounds in grape vine biochar obtained at different temperatures played a major role in adsorbing two heavy metals.By studying the physical and chemical properties of biochar at different pyrolysis temperatures,and combining with the study of the performance and mechanism of grape vine biochar adsorbing cadmium and lead ions,the conditions for preparing grape vine biochar were optimized,which provided some theoretical guidance for the future production of biochar adsorbing materials.The main contents of this paper are as follows:The biochar pyrolyzed at 300,450 and 600 ? showed excellent adsorption capacity.The adsorption capacity of cadmium ion on grape vine was 250.81,327.31 and 377.36 mg?g^-1,respectively.The adsorption capacity of lead ion on grape vine was 156.12,237.25 and 258.86 mg?g^-1.It takes about 7 hours for the obtained biochar materials to react with the solution to reach adsorption equilibrium,and the pH value of the solution should be greater than 3.From the fitting results of Langmuir and Freundlich adsorption models and experimental data,it can be seen that the main mechanism of grape vine biochar adsorbing cadmium ion and lead ion is precipitation.In a word,grapevine biochar is a potential heavy metal adsorbent because of its excellent adsorption performance,low cost and simple processing.