Preparation and characterization of carbon nanomaterials prepared by thermal treatment of biomass DNA

在相同条件下，采用常规水热反应器和微波反应器对DNA碳纳米材料（碳点）进行水热合成，比较产物的荧光特性。研究发现，虽然两种反应产物的发射波长相似，但微波反应器中制备的碳点的荧光强度比传统高温加热反应中制备的碳点高1.5-2倍。然后，以DNA或DNA衍生材料为原料，通过300-500度的热解和200度的水解制备生物炭和水车。通过标准批量吸附实验研究了所得炭对典型环境污染物（重金属离子和药物）的吸附能力。与原始DNA和含有DNA的材料以及标准吸附剂（如活性炭）相比，DNA衍生的生物炭和氢炭对所有研究吸附剂的吸附能力较低（约1 mg/g及以下）。DNA材料在热处理过程中吸附能力的下降是由于含氮基团和其他功能基团的分解，这些功能基团作为与吸附分子结合的活性中心。因此，dna衍生炭作为吸附剂的应用是有限的。此外，结论是DNA中磷酸基团的存在阻止了研究开始时提出的石墨碳结构的形成。

The hydrothermal synthesis of DNA carbon nanomaterials (carbon dots) using a conventional hydrothermal reactor and the microwave reactor under the same conditions were conducted to compare the fluorescent properties of products. It was found that while the emission wavelengths were similar for both types of reaction products, the carbon dots prepared in the microwave reactor had 1.5-2-fold higher fluorescence compared to those obtained in the conventional HT heating reaction.Next, biochars and hydrocars were prepared from DNA or DNA-derived materials by the pyrolytic treatment at 300-500 degrees and hydrolytic treatment at 200 degrees. The obtained chars were studied for their adsorption capacities towards typical environmental pollutants (heavy metal ions and pharmaceuticals) by standard batch adsorption experiments. DNA-derived biochars and hydrochars showed low adsorption capacities (ca. 1 mg/g and below) towards all studied adsorbents compared to the original DNA and DNA containing materials and standard adsorbents such as activated carbon. The decrease in the adsorption capacity during thermal treatment of DNA materials was ascribed to the decomposition of nitrogen-containing and other functional groups that served as active centers for binding with the adsorbing molecules. The application of DNA-derived chars as adsorbents was thus shown to be limited. Furthermore, it was concluded that the presence of the phosphate moieties in the DNA prevented the formation of the graphitic carbon structures suggested in the beginning of the study.