油茶果壳改性生物炭吸附性能及其耦合淹水对土壤Cd形态影响

研究选取湖南典型农业废弃物油茶果壳为原材料，尝试采用Na₂SiO₃溶液浸泡油茶果壳粉末方法，制备改性生物炭（MBC），并开展不同生物炭材料对溶液中镉（Cd）的吸附与其耦合淹水对土壤中Cd的活性阻控性能研究.用扫描电镜（SEM）、比表面积测试（BET）和傅里叶红外光谱（FTIR）等表征手段对生物炭的物理化学性质进行分析.结果显示，MBC相比未改性生物炭（BC）拥有更大的比表面积与更加丰富的官能团种类，且对溶液中Cd²⁺具有更强的吸附能力.土壤淹水实验结果表明，淹水可使土壤pH值升高，同时降低酸可溶态Cd组分含量，且随着淹水时间的延长，土壤酸可溶态Cd含量呈逐渐向残渣态转化趋势，而生物炭添加耦合淹水比淹水对照处理能明显进一步促进可溶态Cd向残渣态转化，降低酸可溶态Cd含量.酸可溶态Cd组分含量与生物炭的添加量呈显著负相关关系，淹水60 d时，5.0%添加量的MBC实验组土壤酸可溶态Cd含量约为0.33 mg·kg^-1，相比仅淹水的对照处理降幅约为45.0%.综上可知，硅酸钠溶液改性油茶果壳生物炭是一种Cd污染水土和土壤治理的新型有效材料，研究结果同时为油茶果壳的资源化途径提供了方法参考.

Adsorption Properties of Oiltea Camellia Shell-Modified Biochar and Effects of Coupled Waterlogging on Soil Cd Morphology

Using oiltea camellia shells, a typical agricultural waste, in Hunan as feedstock, Na₂SiO₃ solution was used to impregnate oiltea camellia shells and modified biochar was prepared under oxygen-limited conditions. We have studied the adsorption efficiencies of Cd in solution by different biochars and the resistance efficiencies of Cd activity in soil by biochars coupled with flooding. Scanning electron microscopy, Brunauer-Emmett-Teller analysis, and Fourier transform infrared spectroscopy were used to reveal the physicochemical properties of the biochars. The results showed that compared with the camellia oil shell biochar, the modified camellia oil shell biochar (MBC) obtained more special surface areas and functional groups, which showed stronger adsorptive capacities for Cd. A waterlogging soil incubation experiment showed that flooding could simultaneously increase the soil pH values and decrease the acid-soluble Cd component. More available Cd was transformed into the residual state as the flooding time increased, and biochar addition coupled with flooding could lead to further improvement of acid-soluble Cd transformation to the residual state and reduce the acid-soluble Cd content. The concentration of acid-soluble Cd was significantly negatively correlated with the increase in biochar dosage. At 60 d of flooding, the acid-soluble Cd content was 0.33 mg·kg^-1 (a decreased amplitude of approximately 45.0%) in 5.0% additional of MBC disposal. Thus, sodium silicate-modified biochar is a novel and effective material for the remediation of Cd-contaminated water and soil, and the research results provide a reference for the resource recovery of Camellia oleracea organic waste.