Emerging advancements in ecofriendly nanosorbent technology accompanied with natural fillers: a systematic review

Increasing incidence of oil spills due to maritime transportation and improper disposal of refinery waste has caused severe damage to marine ecosystems. Various traditional technologies have been developed to mitigate oil pollution. However, these methods require high-cost and complex multi-step treatments that limits their large-scale applicability. Sorbent-based remediation, particularly porous polymeric sorbents (synthetic and natural), has emerged as a promising strategy for oil spill cleanup. Synthetic polymeric sorbents exhibit high oil sorption capacities, but their non-biodegradability raises ecological concerns. Consequently, research has shifted toward nature-friendly biodegradable polymeric sorbents. Despite their environmental benefits, these sorbents often suffer from inherent hydrophilicity, limited oil selectivity, and low mechanical strength, that restricts their long-term performance. To enhance the oil selectivity and water repellency of biodegradable sorbents, various surface modification strategies have been explored. Chemical surface modifications with hydrophobic materials such as, CNTs, graphene oxide, and fluoroalkanes have proven to be effective in improving the water repellency, but raises concerns regarding toxicity and environmental safety. Recent advancements focus on integrating natural fillers, biomimetic surface engineering, and functional biocompatible coatings to achieve superior oil-water separation performance, while maintaining environmental safety. This review systematically analyzes time-based evolution and advancements in biodegradable polymeric nanosorbents, emphasizing their fabrication techniques, biocompatible surface modifications, and integration of natural fillers for enhanced oil-water separation. A comprehensive literature search was conducted across multiple electronic databases (Web of Science, ScienceDirect, PubMed, and Google Scholar), covering studies published from 2015 to 2024. Studies were selected based on keyword searches and reference mining to ensure comprehensive coverage of relevant developments in the field. By providing a comparative analysis of key performance metrics and identifying research gaps, this review highlights the potential of natural fillers and biomimetic strategies using bio-sources for developing next-generation superhydrophobic nanosorbents.