高温与冻融循环对水热炭和生物炭吸附污染物的影响

将农林废弃物通过不同碳化方式制备成水热炭或生物炭,用于土壤改良和环境污染修复,是当前研究和应用的热点领域.由于受到不同自然条件的长期影响,如环境温度变化,水热炭和生物炭会发生老化作用,从而影响其对污染物的吸附能力,因此,评估老化作用对碳化材料吸附能力的影响是一个重要的科学问题.采用高温和冻融循环2种加速老化方式模拟自然...

Effects of High Temperature and Freeze-thaw Cycle Ageing on Adsorption Performance of Hydrochar and Biochar on Pollutants

The application of hydrochar or biochar derived from agricultural wastes into soil amendments and remediation is one of hot topics nowadays. Due to long-term varied natural condition, such as changed ambient temperature, the properties of hydrochar or biochar would change and have some effect on the adsorption capacities. Hence, it is an important issue to assess the adsorption performance of hydrochar and biochar under the effect of ageing. In the study, high temperature ageing and freeze-thaw cycle ageing were used to simulate the changed ambient temperature. The physicochemical properties of fresh and aged rice husk and corn straw derived biochars and hydrochars were compared by multi-techniques of elemental analysis, Fourier infrared spectrometer (FTIR) and scanning electron microscope (SEM). The adsorption capacity and stability of hydrochar and biochar, as well as the effects of different ageing time (e.g., 30, 60, 90 cycles) on their adsorption capacity, were compared by batch experiments. The results showed that biochar had good adsorption stability for Cd (II) and atrazine, while hydrochar had poor adsorption stability for atrazine. The two ageing processes increased the oxygen containing functional groups of hydrochar and biochar, thus enhancing the adsorption capacity of Cd (II) and atrazine. In high temperature and freeze-thaw environment, biochar was more susceptible to environmental effects than hydrochar as the ageing time increased. The obtained results from this study suggest us to consider the rational use of hydrochar and biochar in the environmental remediation.