A Review of Advancements in Solvent Recovery from Hazardous Waste

Abstract

The recovery and reuse of organic solvents from hazardous waste is a sustainable alternative to conventional solvent disposal options. The current work explores recent breakthroughs as well as the versatility of available solvent recovery technologies. Membrane-based separation processes are emerging as superior alternatives to traditional energy-intensive distillation due to (a) recovery of high-purity products, (b) significantly reduced energy consumption, (c) lower operational expenses, and (d) emissions reduction. Nevertheless, distillation-based technologies remain relevant due to their versatility in handling complex solvent mixtures. Hybrid methods, combining the separation and energy efficiency of membranes with the resilience of distillation, offer an optimal solution that is cost-effective and has a low environmental impact. Technology hybridization reduces operational energy and emissions while overcoming the constraints of stand-alone membrane systems such as the high capital requirement. For instance, integrating vapor permeation with distillation reduces ethanol dehydration energy requirements by 63%, while hybrid pervaporation-distillation achieves a 91% reduction in life cycle emissions for isopropanol recovery in comparison to conventional methods. Vapor permeation-distillation further demonstrates 77% cost savings compared to conventional azeotropic distillation. Additionally, adsorption-based approaches, such as hot gas pressure swing adsorption, yield 83–89% isopropanol from aqueous mixtures at industrial scales. Recent advancements in membrane materials, including poly(vinyl alcohol)-silica nanoparticle composites, have improved energy efficiency and reduced CO₂ emissions during separation processes. Future advancements in solvent recovery would facilitate zero-liquid discharge and circular economy objectives, a fundamental aspect of sustainable industrial processes.