Jiazhou He,Jieqin Zhou,Kui Yang,Liang Luo,Pan Wang,Zhiwei Wang,Jinxing Ma
Recovering ammonia from waste streams ( e.g. , urine) is highly desirable to reduce natural gas-based NH 3 production and nitrogen discharge into the water environment. Electrochemical membrane stripping is an attractive alternative because it can drive NH 4 + transformation to NH 3 via cathodic OH − production; however, the conventional configurations suffer from relatively low ammonia recovery (<80 %) and significant acid/material usage for ammonia adsorption. To this end, we develop a novel stack system that simply uses an oxygen evolution reaction to in-situ produce acid from water, enabling chemical-free ammonia recovery from synthetic urine. In batch mode, the percentage removal and recovery increased respectively from 74.5 % to 97.9 % and 81.8 % to 92.7 % when the electrode pairs increased from 2 to 4 in the stack system. To address the gas-sparging issue that deteriorated ammonia recovery in continuous operation, pulsed electric field (PEF) mode was applied, resulting in ∼100 % recovery under optimized conditions. At an ammonia removal rate of 35.1 g-N m −2 h −1 and electrical energy consumption of 28.9 kWh kg-N −1 , our chemical-free system in PEF mode has achieved significantly higher ammonia recovery (>90 %) from synthetic urine. The total cost to recover 1 kg of NH 3 –N from real human urine was $15.9 in the proposed system. Results of this study demonstrate that this novel approach holds great promise for high ammonia recovery from waste streams, opening a new pathway toward sustainable nitrogen management.
El-diehy Mahmoud A.,Farghal Ibrahim I.,Amin Mohamed A.,Ghobashy Mohamed mohamady,Nowwar Abdelatti I.,Gayed H. M.
The main focus of this study was on using radiation to make an ultra-absorbent hydrogel (UAH) from sodium alginate (SA) and gelatin (GL) biopolymers. This UAH can effectively handle water and nitrogen in wheat farming during drought stress. The hydrogel was synthesized by gamma irradiation-induced SA/GL/polyacrylamide crosslinking at 10–40 kGy. Varying SA/GL ratios affected swelling and the gel fraction of SA/GL/PAm hydrogels. The (SA/GL 17/83) hydrogel exhibited a 40.03 g/g swelling degree, while increasing SA content resulted in higher swelling, peaking at 75.5 g/g for (SA/GL 83/17). This indicated a synergistic interaction between SA and GL. The gel fraction also increased from 76.8 to 90.3%, with a higher GL content reflecting increased crosslinking. After multiple hydrolysis cycles, the hydrogel achieved 1293 (g/g) swelling and 36 days of water retention. When applied to wheat ( Triticuma estivum ) under drought stress, it significantly improved shoot length (18%), root length (43%), shoot fresh weight (49%), and shoot dry weight (51%) under extreme drought. The significant increases in protein and carbohydrate content in both shoots (up to 32% and 19%, respectively) and grains (up to 21% and 24%, respectively), along with the reduction in proline content (up to 38%), demonstrate that ultra-absorbent hydrogel (UAH) effectively enhances nitrogen content, photosynthesis, and overall plant health in wheat under varying drought stress levels. This novel SA/GL-based UAH holds promise for addressing water scarcity and agricultural challenges, offering a sustainable solution for water and nitrogen management under drought stress.
Yan Wang,Xinlin Zhao,Negar Omidvar,Mengting Liu,Dongsheng Zou,Manyun Zhang
Fungicides and nitrogen (N) fertilizers are essential to maintain plant yield in current intensive agriculture. Percarbamide is a novel type of N fertilizer with strong oxidizing property, and the nitrification inhibitor is widely used in agricultural production. It may be feasible to apply percarbamide and nitrification inhibitor as N management to promote fungicide dissipations in soil-plant system. This study quantified the effects of percarbamide and nitrification inhibitor dicyandiamide (DCD) and 3, 4-dimethylpyrazole phosphate (DMPP) on carbendazim residues, and microbial communities of soil-plant systems, and relationships among carbendazim residues, soil and endophytic microbial communities and plant yields were also comprehensively quantified. Compared with the control, the percarbamide significantly reduced soil carbendazim residues by 29.4% but enhanced the lettuce yield by 28.0%. Soil carbendazim residues were significantly and negatively correlated with the soil total N and NO 3 − -N contents. Soil microbial community structures and co-occurrence networks were more sensitive to N management than their endophytic counterparts. In comparison to the percarbamide alone, the DCD significantly increased the nodes of soil fungal community co-occurrence network which were positively correlated with the plant yield. The DCD outweighed DMPP in increasing the lettuce yield and soil fungal community stability and reshaping soil bacterial community structure. Our study suggested that soil microbial communities were more sensitive to percarbamide and nitrification inhibitor applications than their endophytic counterparts under fungicide pressure and that the DCD outweighed DMPP in reshaping microbial communities. The integrated applications of percarbamide and nitrification inhibitors were promising soil N management strategies to promote fungicide removal and stimulate microbial community in the soil-plant systems.
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