International Journal of Science, Engineering and TechnologyAuthors: Nwanze Tobechukwu Joseph, David Chinonso Anih, Dominica Peace Chinedu, Uguru Chukwudi Clement
Abstract: This systematic review synthesizes empirical evidence on the occurrence, mobilization, and management of per- and polyfluoroalkyl substances (PFAS) and selected heavy metals in recycled construction and demolition (C&D) material streams. A PRISMA-style protocol guided searches of Web of Science, Scopus, PubMed, and Google Scholar for 2010–2025, completed on 25 May 2025. From 1,890 records screened, 24 studies were included in the review and 18 Studies included as background/methodological references. Extracted data comprised bulk contaminant inventories, short- and long-term leaching experiments, thermal rework simulations, mass-balance assessments of recycling operations, and reported monitoring and decision frameworks. Results demonstrate material- and process-dependent variability in contaminant distribution and mobility. Textile-derived products, including carpets and padding, exhibited higher median ΣPFAS concentrations with positive skewness, whereas mineral matrices reported lower per-mass ΣPFAS but yielded mobile fractions concentrated in fine particles. Processed fines and dust consistently exhibited enrichment of PFAS and metals, with reported enrichment factors commonly between two and five relative to bulk feed. Short-term batch leach tests produced variable aqueous export of target PFAS, while column and monolith experiments indicated diffusion-limited long-tail release from encapsulated matrices. Thermal rework simulations detected volatile and semi-volatile fluorinated species and condensable byproducts at intermediate temperatures, indicating gas-phase transformation pathways and particulate emissions during milling and hot recycling. Treatment and mitigation performance was matrix dependent. Adsorption achieved high removal efficiency for dissolved PFAS under optimized conditions. Washing reduced surface-accessible mobile fractions by approximately 30–80% but generated concentrated residual streams requiring management. High-temperature thermal treatment approached near-complete destruction of target organofluorine compounds under controlled conditions but produced secondary waste streams necessitating capture and abatement. Decision frameworks reported in the literature favor a tiered approach: initial screening, targeted characterization (for example, TOP assay and column tests), selection of containment, treatment, or destruction measures, and monitoring-informed feedback. Key limitations include heterogeneous analyte suites and detection limits, limited long-term field monitoring for multidecadal desorption, and inconsistent experimental designs. Recommendations include harmonized reporting standards, coordinated long-term and multi-matrix monitoring, expanded investigation of thermal transformation products, and incorporation of monitoring data into conditional decision pathways to support evidence-based reuse of recycled C&D materials.
DOI: https://doi.org/10.5281/zenodo.18479095
