The original biochar (BC) was prepared by pyrolysis using chestnut shells as raw materials, and then the phosphate-modified nitrogen-doped biochar (NP-BC) was prepared by nitrogen doping and phosphate modification methods. The adsorption performance of BC and NP-BC for uranium in wastewater was investigated. The surface morphology and elements of BC and NP-BC were analyzed by means of SEM, EDS, BET, FT-IR and XPS, and the adsorption mechanism of BC and NP-BC for uranium was discussed. The results show that for the wastewater with an initial mass concentration of uranium of 10 mg/L and initial pH of 4, under the conditions of NP-BC dosage of 0.2 g/L and reaction temperature of 30 ℃, the adsorption removal rate of U(Ⅵ) can reach 99.32%. The influence of coexisting anions and cations on the division of U(Ⅵ) in NP-BC increases with the increase of ion concentration. The adsorption process is more suitable to be described by the pseudo-second-order kinetic model and the Langmuir isothermal adsorption model. It is concluded through FT-IR and XPS analysis that the adsorption mechanism of uranium by NP-BC is the coordination effect and reduction effect of oxygen-containing functional groups, nitrogen-containing functional groups and phosphate groups.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |