Enhanced technology of phytoremediation

The enhanced technology of phytoremediation has the advantages of low treatment cost, good purification effect, low environmental risk and environmental aesthetics. However, some hyperaccumulators grow slowly and their biomass is generally low; the activity of heavy metals in the soil is very low; the roots of plants are distributed in the surface of the soil, and the remediation effect of deep soil is poor; the nutrients of the soil to be repaired are seriously insufficient. It is necessary to take a series of strengthening measures to improve the efficiency of phytoremediation. The strengthening technologies of phytoremediation include chemical strengthening, microbial strengthening, animal strengthening, carbon dioxide strengthening, agronomic and management measures strengthening, etc.

Measurement of Dynamic Elastic Modulus and Poisson’s Ratio of Chemically Strengthened Glass

Glass with strong durability and transparency has been in the spotlight in various fields, including displays. Elastic and shear moduli and Poisson’s ratio are important properties of glasses. The purpose of this study is to evaluate the change in mechanical properties, such as the dynamic elastic modulus and Poisson’s ratio, with respect to the chemical strengthening time of glass for display applications, as measured by static and dynamic methods. The basic measurement principle of the dynamic method is to measure acoustic speed or resonant frequency using an ultrasonic generator. The mechanical properties of both non-strengthened and chemically strengthened glasses were investigated. It was found that the strength of the chemically strengthened glass decreased when chemical strengthening time increased. Chemical strengthening increased the bending strength and decreased the elastic modulus due to the introduction of compressive residual stress at the surface.

Effect of Chemical Enhancing-Technology on the Properties of Recycled Aggregate

Strengthening the attached old cement mortar of recycled aggregate (RA) is a common approach to enhance the RA properties. In this study, four representative chemical enhancing-technologies were chosen. Through the analysis of physical properties, mechanical properties, and shape indexes, the changes of performance before and after strengthening were tested, so as to grasp the influence of chemical enhancing-technologies on the performance of RA. The results indicated that the chemical strengthening methods had obvious influence on the physical properties of RA, such as density and water absorption. Due to the different chemical enhancing mechanism, the influence trend and range were varied. The mechanical properties of RA such as crushing value and abrasion value were obviously improved by chemical enhancement. However, chemical enhancement had an effect on the shape of RA, which will slightly reduce the angularity index and sphericity index. The texture index of RA with C-3 and C-7 decreased sharply, but texture index increased after abrasion, and the discrepancy of aggregate texture index of different enhancing methods is significantly reduced. The microanalysis exhibited that the aggregate surface structure with C-3 and H was large, but there were a lot of fine structures on the aggregate surface with C-7 and N-P. Different chemical enhancing methods have different effects on the mechanical performance and microstructure of RA, but it should be noted that the fluctuation of RA performance tends to increase.