The Research In Plant Density And Pyrolysis Decomposition Of Peteris Vittata L.

With the quickly developed of international economy, civilization and technology, and the rapidly upgraded standard of living for people who pay more and more attention to the environmental problem. Phytoremediation was a burgeoning and promising technique for soil, water and air pollution resumed. Thanks to advanced research for phytoremediation, the intensified technique of phytoremediation was indispensable condition in practical remediation. In this paper, we reviewed articles of intensified technique using in phytoremediation of heavy metal polluted soils, the practical trial of plant density for arsenic hyperaccumulator, the pyrolysis condition and incineration mechanism for harvest of plant were under experiment.(1) A field trial for plant density has been used for practical remediation in 2004 and 2005, it has four treatments, 10 cm×10 cm,20 cm×20 cm,10 cm×40 cm and 40 cm×40 cm, respectively. The results were follows: the optimization plant density was 20 cm×20 cm; Peteris vittata L. was a herbaceous plant fit to adequacy increased density for enhancing the biomass and removalling of arsenic; with increased the plant density, the plant were accumulated more proportion arsenic in their fronds, and then made promote the efficiency of arsenic removal from contaminated soils.(2) It was a complicated pyrolysis course for plant incineration. In order to get optimum temperature rise rate, atmosphere and interval time in the course of thermal decomposition of arsenic hyperaccumulators. According to Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) curves, the conclusion were follows: from four heating rates, 10 ℃/min, 25 ℃/min, 50 ℃/min and 100 ℃/min, respectively. Under the heating rates of 25 ℃/min, fine thermal analysis curves were gotten, pyrolysis course focus between 200⁴60 ℃, complete time feasible, which was the optimal temperature rise rate. Under the different atmospheres of N₂ and air, the existence of O₂ in the air could strongly affect the thermal decomposition of the two arsenic hyperaccumulators. In the TG curves, the decomposition took place at lower temperatures and a final combustion process was observed; In the DTG and DTA curves, it is clearly seen that the peaks increase in the air. The four interval time treatments had little different for the thermal decomposition curves. So the thermal analysis for arsenic hyperaccumulators would select heating rates at 25 ℃/min, pyrolysis atmosphere in the...