Reusable and Biodegradable Separation Membranes Prepared from Common Mushrooms for the Removal of Oily and Particulate Contaminants from Water

Abstract

Mushroom chitin membranes with controllable pore structures were fabricated through a simple process with naturally abundant Agaricus bisporus mushrooms. A freeze-thaw method was applied to alter the pore structures of the membranes, which consist of chitin fibril clusters within the glucan matrix. With tunable pore size and distribution, mushroom chitin membranes could effectively separate stable oil/water emulsions (dodecane, toluene, isooctane, and chili oil) with various chemical properties and concentrations and particle contaminants (carbon black and microfibers) from water. Chitin fibrils tightly pack with each other to form a dense membrane, leading to no permeation of contaminants or water. An increasing number of applied freezethaw cycles confers more tortuous pore structures throughout the mushroom chitin membranes, leading to higher flux while maintaining rejection performance. The 3D simulation constructed by the X-ray computed tomography and GeoDict software also demonstrated capturing a considerable amount of contaminants within the membranes' pores, which can be easily removed by water rinsing for further successive filtration. Furthermore, mushroom chitin membranes were almost completely biodegraded after approximately a month of being buried in the soil or kept in a lysozyme solution while possessing mechanical durability demonstrated by consistent filtration performance for repeated usage up to 15 cycles under ambient and external pressure. This research is a proof of concept that mushroom-derived chitin develops functional and biodegradable materials for environmental applications with scalability.

Construction of Waste Paper-Chitosan-Based Membranes with pH-Tunable Surface Charge for Efficient Separation of Oil-in-Water Emulsion and Dye

“…In this context, natural biopolymers are promising candidates for the design and construction of adsorption–separation membranes. , Cellulose as one of the most abundant biopolymers on earth has attracted much attention as a promising biomass material to fabricate functional materials due to its advantages of low cost, biodegradability, nontoxicity, eco-friendliness, and high hydrophilicity. , Therefore, numerous cellulose-based membranes with underwater superoleophobic properties have been successfully developed for wastewater treatment such as oil–water separation, dye adsorption, and heavy metal removal. − For example, Chen’s group successfully fabricated the regenerated kapok cellulose fiber membrane with underwater superoleophobicity and satisfactory mechanical properties via dissolution and self-assembled regeneration strategy, which presented outstanding purification efficiency of 99.9% for oily wastewater. Recently, following the principles of sustainability, resource reuse, and environmental protection, numerous cellulose-based membranes fabricated from waste paper (WP) have been developed and successfully employed in the field of wastewater remediation. ,,, WP as one of the most common biomass wastes in our life contains the main component of cellulose (>60 wt %) .…”