Smart Sand by Surface Engineering: Toward Controllable Oil/Water Separation

Abstract

Sand, an abundant resource from the nature, is a promising candidate for oil/water separation. Herein, raw sand was designed with switchable surface wettability to enable recyclability and versatility in practical oil/water separation. The "smart" sand was fabricated by grafting pH-responsive poly(4vinylpyridine) (P4VP) and oleophilic/hydrophobic octadecyltrimethoxysilane (OTS) onto its surface. The decorated sand can be used as the oil sorbent for controllable oil sorption and desorption in response to different pHs, as well as a filter to selectively separate either oil or water on demand. This novel design offers an intelligent, low-cost, large-scale, and highly efficient route to potentially settle the issues of industrial oily wastewater and oil spill.

Special Superwetting Materials from Bioinspired to Intelligent Surface for On‐Demand Oil/Water Separation: A Comprehensive Review

“…[ 133 ] Besides, the poly(4‐vinyl pyridine) (P4VP) copolymers also have been applied in fabricating the pH‐responsive materials. [ 134 ] For example, Li et al. have successfully grafted P4VP polymer on the melamine sponge to realize pH‐responsive property (Figure 17e,f).…”

“…have successfully grafted P4VP polymer on the melamine sponge to realize pH‐responsive property (Figure 17e,f). [ 134b ] The sponge showed switchable wettability between SHB and SHL for oil absorption at pH = 7 and deabsorption at pH = 1 (Figure 17g). Besides, the P4VP‐based copolymers, including the PMMA‐ b ‐P4VP, PDMS‐ b ‐P4VP, and PS‐ b ‐P4VP, with different copolymers and preparation methods have been fabricated with high separation performance.…”

“…Reproduced with permission. [ 134b ] Copyright 2017, Elsevier. h) Schematic illustration of the preparation of V‐shaped brush/PDA‐modified SSM with pH‐responsive property.…”

“…[133] Besides, the poly(4-vinyl pyridine) (P4VP) copolymers also have been applied in fabricating the pH-responsive materials. [134] For example, Li et al have successfully grafted P4VP polymer on the melamine sponge to realize pH-responsive property (Figure 17e,f). [134b] The sponge showed switchable wettability between SHB and SHL for oil absorption at pH = 7 and deabsorption at pH = 1 (Figure 17g).…”

Highly Transparent, Self-Reinforced, and Hydrophobic Cellulose Acetate Films Fabricated Based on Thermal Stretching and Surface Engineering

“…Surface engineering is a widely employed strategy to change the inherent surface properties of materials and impart them with various functions, − and surface porous materials with a variety of functionalities have been developed in recent decades. As far as we know, there are very few works about surface engineering of CA, and imparting CA films with hydrophobicity and high transparency simultaneously via surface engineering is of great significance but remains a challenge.…”