| Approval of deep eutectic solvent be a green additive for manufacturing and modifying reverse osmosis membranes; experimental and life cycle assessment (LCA) study |
| کد مقاله : 1165-ICOC |
| نویسندگان |
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احمد دهقان *، وحید وطنپور دانشگاه خوارزمی |
| چکیده مقاله |
| Introduction: Among the water treatment methods, membrane filtration, particularly reverse osmosis (RO) membrane, is one of the most valuable and practical approaches. However, membrane polymer sheets suffer from fouling issues, which reduce the membrane life and water quality as well as increase the operation pressure and energy consumption. There are many approaches and modifier agents for improving the membrane performance development. Among them, deep eutectic solvent (DES) is a very efficient and environmentally friendly additive [1]. However, this claim needs approval. One well-established environmental assessment tool is life cycle assessment (LCA), which is performed following four interdependent phases: (1) goal and scope definition, (2) listing and quantification of material and energy flows from and to the environment in a life cycle inventory, (3) life cycle impact assessment (LCIA) methodologies, and (4) review [2]. Hence, in this work, the being a green additive of DESs was systematically investigated by the LCA approach. Experimental: All additives and membranes were fabricated in the same lab and tested with the same equipment. The LCA study was done regarding the ISO 14044 guideline with the help of ReCiPe and IPCC methods for 1 L of treated water and 1 m2 of fabricated membrane. Results and Discussion: The results of the performance evaluation indicated that the DES additive has better water permeability than the nanomaterials. Also, the DES-modified membrane showed better chlorine resistance than the other membranes. Moreover, the DES-modified membrane, except in one case, had better long-time antifouling performance. As well, the salt rejection of the DES membrane with a 98% value is acceptable. The LCA results indicated that the main effects of fabrication and water treatment of all fabricated membranes are Human carcinogenic toxicity, freshwater ecotoxicity, and marine ecotoxicity. However, when utilizing DES as an additive, all environmental and human bad effects, especially in the membrane fabrication, disappear and become almost zero. This result was again confirmed even after a 100-year approach assessment. There are several reasons for these observations. First, the natural product was used for the synthesis of DES. Also, the fabrication of DES just needs 4 h of stirring at 50 °C, which is not comparable to the complex synthesis of nanomaterials containing hazardous substances and solvents. Second, the DES-modified membrane has higher performance than the nanomaterials-modified membrane, which leads to using lower energy for the water treatment. Third, the DES amount for the fabrication of the RO membrane was just 0.0025 wt.%, which is remarkably lower than the nanomaterials [1,3]. Conclusion: the results of this study showed that the DES is a green additive for the fabrication of high-performance RO membranes from both points of view of water treatment performance and environmental effects. |
| کلیدواژه ها |
| Deep eutectic solvent; life cycle assessment; green chemistry; environmental protection; RO membrane |
| وضعیت: پذیرفته شده |