生物熱解碳的化學指紋和穩(wěn)定同位素特征及其環(huán)境應用研究.pdf

1、Biomass-derived pyrogenic carbon (biochar) is a carbon-rich material produced bythermochemical treatment of lignocellulosic biomass in the absence of oxygen (oroxygen-limited conditions).Due to its highly stable structur

2、e and persistence in nature,biochar is believed to be chemically and biologically inert having the potential tomitigate global warming by long-term C-sequestration and can stay in soil for severalcenturies-millennia.Addi

3、tional advantages of biochar include improved soilproductivity/fertility, environmental remediation, wastewater treatment and solid fuel
　　for energy production.Inventiveness in biochar science for its agro-environmen

4、tal andclimate benefits is fast emerging among researchers, who are swiftly acceleratingstudies to explore its potential.Although biochar-based science is progressing rapidly,many areas of uncertainty need to be addresse

5、d.
　　In the present study, we conducted series of experiment including production andmodification of biochars, characterizations using an array of techniques (SEM, TEM,HRTEM/SAED, TEM-EDS, FTIR, TGA, XRD, Brunauer-Emm

6、ett and Teller (BET),stable isotope measurement, Elemental Analyzer and ICP-MS) and their environmentalapplications: i.e.;
　　(1) co-firing of pyrolyzed biomass feedstocks with coal for cleanenergy and emission-reducti

7、on of potentially toxic elements (PTEs);
　　(2) efficientremoval of metal ions from aqueous medium using biochar-coated RBC-TiO2@Cnanocomposite;
　　(3) addition of biochar as soil amendment to minimize the health ris

8、ksof PTEs;
　　(4) priming effects of biochar on native soil organic carbon and its potentialfor carbon sequestration.
　　A total of 168 biochar samples were prepared under various operating conditions(temperature: 30

9、0-700 ℃, retention time: 15-90 min, heating rate: 1-10 ℃ min-1, gasflow rate: 20-200 sccm (ml min-1) and particle size: ＜200-10 mesh) using eight (8)biomass feedstocks.Results revealed that temperature, gas flow rate and

10、 particle sizehave significant control on product yield and physico-chemical characteristics ofbiochars compared to the other operational conditions.In addition, temperature,retention time and heating rate remarkably inf

11、luenced stabilization of PTEs in biochar.No potential ecological risk was observed during pyrolysis process, the RI values forsingle elements demonstrated low risk at all operating conditions and its valuesignificantly d

12、ecrease with increasing the values of operating conditions.The isotopicmeasurements revealed that all operating conditions do not significantly change thetotal (δ13Ctotal) and organically bound (δ13Corg) C isotope values

13、 from the originalbiomasses; however these significantly influenced carbonate bound C and O isotopevalues (δ13Ccarbonate and δ18Ocarbonate).The characterization and laboratoryexperimentations indicate that biochar synthe

14、sized under higher pyrolysis temperature,extended retention time and, lower heating and gas flow rates with fine particle size hasutility as a potential C-sequestration and remedial agent to mitigate global climatechange

15、 and adsorption of environmental polluants, respectively.In additions, modifiedbiochar (biochar coated RBC-TiO2@C nanocomposite) has strong ability to adsorbedenvironmental pollutants from aqueous medium.Furthermore, our

16、 results show thatbiochar as a renewable solid bio-fuel source due to higher calorific values, is a suitableoption for their use in existing coal-fired energy generation system to achieve theenvironmental friendly clean

17、energy and reduction of gaseous PTEs emission.
　　Key words:Pyrogenic carbon (biochar); array-based chemical fingerprinting;physico-chemical characteristics; potentially toxic elements; stable isotopecomposition; envir