Synchronous oil/water separation and wastewater treatment on a copper-oxide-coated mesh

Double-drying 3D lamellar-structured aerogel membrane for efficient oil-water separation and long-lasting antibacterial activity

Conventional oil-water separation membranes are difficult to establish a trade-off between membrane flux and separation efficiency, and often result in serious secondary contamination due to their fouling issue and non-degradability. Herein, a double drying strategy was introduced through a combination of oven-drying and freeze-drying to create a super-wettable and eco-friendly oil-water separating aerogel membrane (TMAdf). Due to the regular nacre-like structures developed in the drying process and the pores formed by freeze-drying, TMAdf aerogel membrane finally develops regularly arranged porous structures. In addition, the aerogel membrane possesses excellent underwater superoleophobicity with a contact angle above 168° and antifouling properties. TMAdf aerogel membrane can effectively separate different kinds of oil-water mixtures and highly emulsified oil-water dispersions under gravity alone, achieving exceptionally high flux (3693 L·m-2·h-1) and efficiency (99 %), while being recyclable. The aerogel membrane also displays stability and universality, making it effective in removing oil droplets from water in corrosive environments such as acids, salts and alkalis. Furthermore, TMAdf aerogel membrane shows long-lasting antibacterial properties (photothermal sterilization up to 6 times) and biodegradability (completely degraded after 50 days in soil). This study presents new ideas and insights for the fabrication of multifunctional membranes for oil-water separation.

Superhydrophilic-superhydrophobic integrated system based on copper mesh for continuous and efficient oil-water separation

In petroleum, petrochemicals, metallurgy, and chemical industries, a significant volume of oily wastewater is unavoidably generated throughout the production processes. This not only harms the environment but also brings about diverse adverse effects on social and economic progress. In this study, copper mesh separation membranes exhibiting superhydrophobicity and superhydrophilicity/underwater superoleophobicity were fabricated through in situ oxidation, chemical vapor deposition, and other physical and chemical modification techniques. Moreover, copper meshes possessing contrasting wetting properties were incorporated into a system combining superhydrophilicity and superhydrophobicity enabling the continuous and efficient separation of mixed oil-water liquids. The separation efficiency of both the superhydrophobic and superhydrophilic membranes surpassed 99.0% and remained above 97.0% after 15 days of continuous use, showcasing the remarkable effectiveness and durability of the integrated system design. This research presents a straightforward and cost-effective design approach for the large-scale treatment of oily wastewater in industrial settings, which is expected to have extensive applications in practical production.

Wastewater in the food industry: Treatment technologies and reuse potential

Water is the most extensively used raw material in the food and beverage industry. This industrial sector has a negative impact on the environment and economy as a result of rising water demand and wastewater production. With the increasing scarcity of drinking water, the reuse of wastewater streams has become an important economic and ecological concern. Therefore, the optimisation of water consumption and wastewater reuse in the food industry is essential. On the other hand, several countries limit the reuse of wastewater because of legal curtailment, public health and safety concerns. This represents a major challenge for both industries and administrations due to the technical complexity and financial costs involved. The present review aims at addressing the key issues related to water consumption, wastewater generation, treatment and successful implementation cases of water reuse in the food and beverage industry. Moreover, the various case studies of already employed technologies for the food industry wastewater treatment and reuse have been analysed for their performance. Also, this review reveals future research on the application of other innovative technologies such as ultraviolet irradiation and micro electrolysis. However, the successful implementation of reuse strategies is associated with the holistic evaluation of local factors such as governmental incentives, social acceptance and legislation harmonisation related to the cost, risks, and environmental performance.