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Aimed at the problem of environmental uranium pollution caused by uranium-containing wastewater generated in the process of nuclear energy development and application， by loading g-C3N4 on chitosan （CS） through the cross-linking method， g-C3N4/CS composite was synthesized and used to remove U（Ⅵ） from aqueous solutions. The surface properties and the interaction mechanism of g-C3N4/CS were analyzed. The results show that when the adsorbent dosage of g-C3N4/CS is 0.2 g/L， mass fraction of g-C3N4 is 20%， adsorption time is 120 min， adsorption temperature is 308 K， and pH is 6， the maximum adsorption capacity of g-C3N4/CS on U（Ⅵ） reaches 324.45 mg/g. The adsorption of U（Ⅵ） by g-C3N4/CS involves a spontaneous endothermic process that follows the Langmuir isotherm model and quasi-second-order kinetic model. The adsorption mechanism of U（Ⅵ） by g-C3N4/CS is primarily attributed to the coordinated complexation of functional groups such as —NH，—OH，C—O，C=O，and C—N. The results of the recycling experiments show that g-C3N4/CS has good reusability.

【Objective】 Surfactants are soil conditioners to improve soil water flow and reduce soil erosion. This paper investigates their impact on water-nitrogen transport in soil, as well as yield, quality and root growth of greenhouse lettuce. 【Method】 The experiment was conducted in laboratory using a calcareous cinnamon soil. The soil was amended by three surfactants: HydravanceTM200 (T1, moisturizing and synergistic surfactant mix), Methylglucosan polyether-20 (T2, moisturizing single surfactant), and IrrigAid (T3, moisture-regulating surfactant mix), separately. For each surfactant amendment, there were two nitrogen treatments: without fertilization (N0) and nitrogen fertilization (N1). Soil without amendment by any surfactant was taken as the control (CK). During the experiment, we measured the changes in soil water content and soluble nitrogen content, as well as the growth and yield of the lettuce. 【Result】 ① Compared to CK, T1, T2 and T3 enhanced the lateral movement of water in the soil, thereby leading to an even soil water distribution and a reduction in nitrate nitrogen content in the subsoil layer (20-30 cm). ② According to the pot experiment, the above-ground fresh mass and VC content of lettuce in the T1N1 treatment increased by 26.61% and 175.61%, respectively, in addition to the 2.10 times increase in nitrogen utilization efficiency (P˂0.05). Compared to CKN1, T2N1 significantly increased VC content by 104.88%, while T3N1 significantly increased total root length and volume by 61.98% and 112.90% (P

MnO2/MCM-41 composite was prepared by one-pot method to investigate its removal of Sr2+ from radioactive wastewater. The prepared composite were characterized by SEM，BET，FT-IR. The effects of parameters such as mass ratio，pH，adsorption time and competing ion effect of MnO2 and MCM-41 on the adsorption test were investigated. The results showed that the composite adsorbent could rapidly adsorb Sr2+ in water and reached the adsorption equilibrium in 120 min with the maximum adsorption capacity of 85.46 mg/g. The composite adsorbent had the highest adsorption capacity when the mass ratio of MnO2 and MCM-41 was 4∶1 ，and the composite adsorbent had high adsorption performance in the range of pH 4-9. In addition，the composite adsorbent maintained good adsorption capacity in the presence of Na+，K+，Mg2+ and Ca2+，and the inhibited adsorption capacity followed the order of Na+< K+< Mg2+< Ca2+. The adsorption kinetic data analysis of the pseudo-secondary model fit the adsorption data better than the pseudo-first-order model，indicating that chemisorption dominated the adsorption process. The novel MnO2/MCM-41 composite prepared for the removal of Sr2+ from radioactive wastewater had the advantages of rapid adsorption，high adsorption capacity，selectivity，and the ability to be prepared on a large scale，which made it promising to play an important role in the field of Sr2+ containing radioactive wastewater removal.

Above- and below-ground tree biomass structure and allometric relationships of Abies nephrolepis (Maxim) were assessed in an old secondary forest dominated by A. nephrolepis, Pinus koraiensis, Quercus mongolica, Tilia amurensis, Fraxinus mandshurica and Acer mono in northeast China. Based on the breast-height diameter (D), a total of 21 sample trees were divided into three tree size classes: the small trees (1 cm ⤠D < 10 cm), the medium trees (10 cm ⤠D < 20 cm) and the big trees (D ⥠20 cm). The greatest amount of live branch biomass was located in the middle and bottom layers of the crown, while the largest foliage biomass was found in the middle layer in each tree size category. The relative contribution of canopy biomass components (live branches and foliage) decreased with increasing tree size, while that of coarse root biomass remained almost constant. The relationship between above- and belowground biomass was linear. D and tree height (H) decreased with increasing competition intensity. The small trees had lower average crown ratio and higher average height-to-diameter ratio than those of the medium and big trees. The big trees had higher average stem to foliage mass ratio than those of the small and medium trees. Crown ratio, height-to-diameter ratio and stem to foliage mass ratio were not correlated with competition intensity in the same tree size class. Root to shoot mass ratio was almost constant among tree sizes. Allometric equations based on D gave higher correlations compared to those with other stem diameters: at tree base, at 30-cm height and at crown base.