Insights into the removal of microplastics from water using biochar in the era of COVID-19: A mini review

Microplastics pollution is a modern-day prevalent challenge that poses serious threats to the general wellbeing and sustainability of the planet. Due to their innately persistent nature, extreme durability, and high stability, they exhibit long residence time and could be transferred through the ecological chains. Current days have witnessed an increase in the accumulation of microplastics waste and debris. This is due to the protective measures imposed by governments and the World Health Organization (WHO) as part of the containment and mitigation efforts of the COVID-19 pandemic. Therefore, the development of versatile, robust, flexible, and efficient removal systems has become a necessity in order to control microplastics pollution. Herein, we review the repercussions of the pandemic on the state of microplastics contamination, sources and identification methods of microplastics in water, their toxicity and risks on the environment, as well as their degradation and conventional removal methods. This review focuses on adsorption and the use of biochar as one of the emerging adsorbents for the removal of microplastics. The efficiency of adsorption using biochar, mechanisms, and applications are discussed. The review addresses the increased rates of microplastics occurrence especially during the era of COVID-19, which requires more efficient and lower cost removal methods. The major conclusions drawn from this review include emphasizing the significant potential of adsorption processes in the removal of microplastics. Biochar is present among the available and most efficient biomass adsorbents especially when combined with other materials. Composite biochar materials play an important role in enhancing the removal and immobility of microplastics. However, more research is required to investigate this at a larger scale, improve efficiency and immobilization techniques.