Abstract

The purpose of this paper is to discuss the application of kenaf straw as a building material for phytoremediation of heavy metal-contaminated soil. The kenaf straw core (KSC) content, kenaf fibre content and KSC particle size were used as factors to study the effects of a slightly cadmium-enriched kenaf straw on the mechanical and thermal properties of cement mortar. XRD, thermogravimetry and SEM were also carried out to study the microstructure of the cement mortar. The safety and reliability of the slightly cadmium-enriched kenaf straw in the cement mortar was evaluated by a heavy metal leaching test. The results show that the compressive and flexural strengths of the cement mortar decreased with increasing KSC content, but the 28-day strength of the cement mortar with a maximum KSC content of 8% can still meet engineering requirements. In addition, the cement mortar demonstrated good thermal insulation performance, the thermal conductivity and dry density of the mortar were significantly reduced, and the bond strength and crack resistance of cement mortar were also improved. The cadmium enriched in kenaf straw did not affect the strength of cement mortar, and the leaching concentration of the heavy metal was far below the prescribed safety limit.

摘要

本文旨在探讨红麻秸秆作为建筑材料在重金属污染土壤植物修复中的应用。以红麻秸秆芯（KSC）含量、红麻纤维含量和KSC粒径为因子，研究了微富镉红麻秸秆对水泥砂浆力学性能和热性能的影响。还进行了XRD、热重和扫描电镜来研究水泥砂浆的微观结构。通过重金属浸出试验评价水泥砂浆中微富镉红麻秸秆的安全性和可靠性。结果表明，随着KSC含量的增加，水泥砂浆的抗压强度和抗弯强度降低，但最高KSC含量为8%的水泥砂浆28天强度仍能满足工程要求。此外，水泥砂浆表现出良好的保温隔热性能，砂浆的导热系数和干密度显着降低，水泥砂浆的粘结强度和抗裂性能也得到提高。红麻秸秆中富集的镉不影响水泥砂浆强度，重金属浸出浓度远低于规定的安全限值。