| Today, pollutant abatement had been the indispensable item for the environment protection. The management method had been involved into reducing the detrimental material. However, they would not be satisfied with the current situation. It is very essential for us to exploit a novel low price materials or solutions. Among the methods, the biotechnology had expressed an excellent application prospect.As the realgar tailing had been exploited for a long year, the environment of Shimen County in Hunan Province had been polluted seriously, while Pteris vittata and Pteris cretica had been identified to be arsenic hyperaccumulator, and they were utilized in the soil reparation. However, phytoremediation was limited by time-consuming, environment factors, and the pollutant in the aqueous was devolved uncomfortably.In this article, some endophytes were isolated from hyperaccumulator, and used to react with arsenic and lead. The definite program was written down as follow:1. The determination of arsenic in the hyperaccumulator and the environment was study. As the peraccumulation plants, Pteris vittata and Pteris cretica were picked from Shimen county, Hunan province. After that, the plants were separated into root, stem and leaf. At last, the total arsenic of the samples was determinated by atomic fluorescence spectrometry. On one hand, the result of experiment revealed that the content of arsenic in the soil was very high, and need to be reduced. On the other hand, Pteris vittata and Pteris cretica were identified to potential value due to high arsenic peraccumulation characteristic. The distribution of arsenic in the Pteris cretica and Pteris vittata of Weikuangbian from low to high was stem, root and leaf, while in the Kuangzha was root, stem and leaf. The most concentrated of arsenic in both plants was leaf. This result was in accordance with prior report and offered a good theoretical back ground.2. The endophytes in the hyperaccumulator were isolated and identified. The physiology and biochemistry experiments were also investigated in this section. The hyperaccumulation characteristics of the plants would offer endophytes an arsenic environment, and compel them to form a special resistance to arsenic. The plants like a nature screening washer made the process of isolation and purification easier. By taking full advantage of the characteristic, three entophytes were isolated from the plants, and named them Daye L01, Weikuang L02, Daye S03. The arsenic resistance of these endophytes was6000mg/L,6000mg/L,7000mg/L, respectively, which was higher than those reported in the past. These endophytes had been identified to be Bacillus sp., Bacillus sp., and Agrobacterium sp., respectively. The experiment result had indicated that the arsenic resistance of the endophytes in Pteris cretica was higher than Pteris vittata, which was the same with the result of environment detection.3. High arsenic resistance endophytes were reacted with arsenic in live form. Some of possibility conditions had been devised. The experiment results had expressed those live bacteria cells could not react with arsenic obviously no matter whether there was nutrient in the aqueous. In order to understand why the bacteria had a high resistance and low adsorption of arsenic, the change of EPS (Extra Cellular Polymer) had been devised. And the result indicated that the quality of EPS decreased with the concentration of arsenic increasing. In fact, EPS played no part in resisting arsenic. Furthermore, in according with some bacteria had oxidation of arsenic, this study had investigated in the characteristic of oxidation of arsenic. And the result had expressed that three bacteria had oxidation feature, and the most oxidability of these bacteria was Weikuang L02. This experiment indicated that the arsenic resistance of three bacteria had essential relative with oxidability.4. To research the interaction between the bacteria and arsenic (â…¢,â…¤), lead (â…¡), bacteria was enlarged, sterile and centrifuged to yield to be biosorption material. The result of experiment had demonstrated that the material had no absorbability with arsenic (â…¢, â…¤) at any value of pH, while the material was effective with lead (â…¡), inversely. The highest resistance of lead (â…¡) among the bacteria was Daye L01at1000mg/L. The pH of aqueous, dosage of biomaterial, dynamic of sorption progress, isothermal adsorption experiment and the recycle of biomaterial had been investigated. The result of experiment had shown that the optimum pH of lead (â…¡) aqueous was fixed in5.0, and the optimum concentration of biomaterial was1g/L. The biggest adsorption capacity of lead (â…¡) was93.6mg/g by Langmuir curve fitting at the initial concentration of100mg/L.10minutes had spend until the adsorption balance achieved. Five cycles showed the excellent material. IR, SEM and EDS showed that a plenty of cavity and function group, which was benefit for the adsorption of lead (II), was on the surface of biomaterial.In conclusion, the biomaterial Daye L01was very significant in the adsorption of lead (II) in the wastewater due to the good adsorption of lead (II). |
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