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Myriophyllum aquaticum (M. aquaticum), as a Cd-highly enriched and tolerant species, has greater application in phytoremediation of Cd-polluted waters. Mechanisms of Cd uptake and transport of M. aquaticum were comprehensively investigated in this work. Transport direction of Cd was observed both from the roots to the aboveground and vice versa. The aboveground can be harvested during vigorous growth and flowering periods, further improving the efficient phytoremediation of Cd-polluted wastewater. Moreover, analysis of transpiration inhibition, low-temperature treatment and metabolic inhibition indicated that the uptake and transport of Cd by M. aquaticum can be achieved via the coexistence of the free diffusion-dominated apoplast pathway dominated by transpiration and the ''cellular pathway'' dominated by active absorption, with the active energy-demanding cellular pathway playing a dominant role. The obtained results have important implications in the in-depth exploration of uptake, transport and distribution mechanisms of heavy metals during phytoremediation of aquatic plants.

In recent years, the phenomenon of black–odorous water has occurred frequently, and constructed wetlands have been widely used as an effective means of treating black–odorous water. In order to achieve the goal of low-carbon and high-efficiency long-term clean-up of black–odorous water, the modular constructed wetland system was optimized in this study. The optimized modular constructed wetland consisted of aeration, denitrification, and phosphorus removal, of which the denitrification module was a sulfur–iron autotrophic denitrification unit and the phosphorus removal module was a polyaluminum chloride composite filler phosphorus-removal unit. Experimental findings indicated that modular systems with layout ratios of 1:3:1 (A) and 1:2:2 (B) exhibit outstanding performance in remediating contaminants from black–odorous water. Notably, system B demonstrated superior treatment efficiency. Under conditions of high pollution loading, system B consistently achieved stable removal rates for COD (95.79%), TN (91.74%), NH4+-N (95.17%), and TP (82.21%). The combination of along-track changes and high-throughput sequencing results showed that the synergies among the units did not produce negative effects during the purification process, and each unit realized its predefined function. Changes in the substrate and internal environment of the wetland units caused changes in the microbial populations, and the unique microbial community structure of the units ensured that they were effective in removing different pollutants.

The chemical modification of natural palm fibers with an alkali treatment and the silane coupling agent KH570 were studied to determine the superior mechanical performance and solid engineering application properties of natural fiber/polymer/cement composites. These kinds of natural plant fibers can be easily obtained in China. The characterization of the fibers and composites were performed by Fourier transform infrared spectroscopy, thermogravimetric analysis, mechanical property testing, water absorption testing, and scanning electron microscopy. The results showed that chemical modifications can remove part of the cellulose, hemicellulose, and impurities in the fibers. In addition, the functional groups were confirmed to be grafted onto the fibers, which may cause the fibers to be more compatible with the matrix. Among the fibers studied, the 2 + 5/3% sample (treated first with 2% alkali, then with the 5% silane coupling agent, and subsequently mixed into the system of 3% cement and polymer emulsion) showed a tensile strength of 2.12 MPa, a tensile elongation of 155.114%, and water absorption of 19.65%.

The extensive use of sulfonamides seriously threatens the safety and stability of the ecological environment. Developing green inexpensive and effective adsorbents is critically needed for the elimination of sulfonamides from wastewater. The non-modified biochar exhibited limited adsorption capacity for sulfonamides. In this study, the attapulgite-doped biochar adsorbent (ATP/BC) was produced from attapulgite and rice straw by calcination. Compared with non-modified biochar, the specific surface area of ATP/BC increased by 73.53–131.26%, and the average pore width of ATP/BC decreased 1.77–3.60 nm. The removal rates of sulfadiazine and sulfamethazine by ATP/BC were 98.63% and 98.24%, respectively, at the mass ratio of ATP to rice straw = 1:10, time = 4 h, dosage = 2 g∙L−1, pH = 5, initial concentration = 1 mg∙L−1, and temperature = 20 °C. A pseudo-second-order kinetic model (R2 = 0.99) and the Freundlich isothermal model (R2 = 0.99) well described the process of sulfonamide adsorption on ATP/BC. Thermodynamic calculations showed that the adsorption behavior of sulfonamides on the ATP/BC was an endothermic (ΔH > 0), random (ΔS > 0), spontaneous reaction (ΔG < 0) that was dominated by chemisorption (−20 kJ∙mol−1 > ΔG). The potential adsorption mechanisms include electrostatic interaction, hydrogen bonding, π–π interaction, and Lewis acid–base interactions. This study provides an optional material to treat sulfonamides in wastewater and groundwater.

In this study, a novel lab-scale biofortification-combination system (BCS) of Oenanthe javanica and Bacillus series was developed to improve the treatment ability of vertical subsurface flow constructed wetlands (VSFCW) at low temperatures (0–10 °C). The results showed that BCS-VSFCW overcame the adverse effects of low temperature and achieved the deep removal of nutrients. In addition, the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) by BCS-VSFCW were 38.65%, 28.20%, 18.82%, and 14.57% higher than those of blank control, respectively. During the experiment, Oenanthe javanica and low temperature tolerant Bacillus complemented each other in terms of microbial activity and plant uptake. Therefore, VSFCW combined with Oenanthe javanica and low temperature tolerant Bacillus has a promising future in low temperature (