Deepak Kukkar1, Aruna Rani2, Vanish Kumar3, Sherif A Younis4, Ming Zhang5, Sang-Soo Lee6, Daniel C W Tsang7, Ki-Hyun Kim8. 1. Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India. 2. Material Science Division, Intelligent Materials Pvt. Ltd. (Nanoshel Group, Co.), Punjab, India. 3. National Agri-Food Biotechnology Institute (NABI), S.A.S. Nagar, Punjab 140306, India. 4. Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea; Analysis and Evaluation Department, Egyptian Petroleum Research Institute, 11727 Nasr City, Cairo, Egypt. 5. Department of Environmental Engineering, China Jiliang University, Hangzhou 310018, China. 6. Department of Environmental Engineering, Yonsei University, Wonju 26493, Republic of Korea. 7. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China. 8. Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea. Electronic address: kkim61@hanyang.ac.kr.
Abstract
HYPOTHESIS: Oil spills stemming from supertankers, drilling, and natural events represent a serious problem worldwide due to the potential harms to marine ecosystems and aquatic life. To date, various functional absorbents have been developed to treat spilled oil. Among them, carbon nanotube (CNT)-based aerogels and sponges gained attention due to superior performance in uptake and recovery of various types of oil and organic solvents. CNT aerogel/sponge absorbents are demonstrated for a multitude of merits such as: rapid superhydrophobic/superoleophilic absorption (water contact angle > 150°), high capacity (≥100 mg g-1), large surface area (300-400 m2 g-1)), enhanced strength and flexibility (>95% volume reduction and restoration of pristine morphology at <0.25 MPa stress), mesoporous characteristics with high pore density (pore diameter = 80 nm and >99% porosity), recyclability, and easy surface modification. EXPERIMENTS: This review compares CNT sponge-based absorbents with conventional techniques for remediation/recovery of spilled oil. Typically, synthesis of CNT sponges is performed using chemical vapor deposition (CVD) approach in the presence of a catalyst or using sacrificial removal of template. This work summarizes recent progress in strategies for oil-spill treatment based on CNT sponge techniques. The performance of CNT sponges for oil spill removal was evaluated in terms of their adsorption capacity, compressive stressability, and desorption methods (e.g., heat treatment, burning, or squeezing). FINDINGS: CNT sponges were observed to have high performance for removal of oil spills in terms of key performance metrics. This review offers valuable insights into the current state of CNT-mediated oil-spill cleanup technologies and guidance for future research at the same time. This literature survey would help the stakeholders (researchers, scientists, entrepreneurs, and commercial houses) pursue contamination-free water.
HYPOTHESIS: Oil spills stemming from supertankers, drilling, and natural events represent a serious problem worldwide due to the potential harms to marine ecosystems and aquatic life. To date, various functional absorbents have been developed to treat spilled oil. Among them, carbon nanotube (CNT)-based aerogels and sponges gained attention due to superior performance in uptake and recovery of various types of oil and organic solvents. CNT aerogel/sponge absorbents are demonstrated for a multitude of merits such as: rapid superhydrophobic/superoleophilic absorption (water contact angle > 150°), high capacity (≥100 mg g-1), large surface area (300-400 m2 g-1)), enhanced strength and flexibility (>95% volume reduction and restoration of pristine morphology at <0.25 MPa stress), mesoporous characteristics with high pore density (pore diameter = 80 nm and >99% porosity), recyclability, and easy surface modification. EXPERIMENTS: This review compares CNT sponge-based absorbents with conventional techniques for remediation/recovery of spilled oil. Typically, synthesis of CNT sponges is performed using chemical vapor deposition (CVD) approach in the presence of a catalyst or using sacrificial removal of template. This work summarizes recent progress in strategies for oil-spill treatment based on CNT sponge techniques. The performance of CNT sponges for oil spill removal was evaluated in terms of their adsorption capacity, compressive stressability, and desorption methods (e.g., heat treatment, burning, or squeezing). FINDINGS: CNT sponges were observed to have high performance for removal of oil spills in terms of key performance metrics. This review offers valuable insights into the current state of CNT-mediated oil-spill cleanup technologies and guidance for future research at the same time. This literature survey would help the stakeholders (researchers, scientists, entrepreneurs, and commercial houses) pursue contamination-free water.