We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Effects of chemical pretreatments on microplastic extraction in sewage sludge and their physicochemical characteristics
Summary
This study evaluated different chemical pretreatment methods for extracting microplastics from sewage sludge, finding that some treatments can alter the physical and chemical properties of plastic particles in ways that affect identification. Choosing the right extraction method is important for accurately characterizing microplastic contamination in biosolids.
Sewage sludge is a primary pathway for microplastics (MPs) entering into terrestrial ecosystems. However, a standardized method to analyze MP in sludge is lacking due to its high organic matter. This study investigated the extraction efficiency of six MPs in five solid matrices, i.e. sewage sludge, cattle manure, soil, sediment and silicon dioxide. Results show lower extraction efficiency of 87.2% for MPs in sludge compared with that in other matrices, especially polyethylene terephthalate (PET) (only 27.8%). The possible reason was that the presence of extracellular polymeric substances within the sludge hinders the MPs to float. Therefore, five protocols, i.e. hydrogen peroxide (HO), Fenton, nitric acid (HNO), hydrochloric acid (HCl) and sodium hydroxide (NaOH) were used to pretreat the sludge and optimize the MP extraction. The sludge pretreated by HO, Fenton and 1 M of acids had higher MP extraction efficiency than the raw sludge due to higher extraction of the PET. The MP extraction efficiency in the sludge first increased, and subsequently decreased with the soluble chemical oxygen demand (SCOD) content, implying that moderate dissolution of sludge organic matter is beneficial to the MP extraction. Quantitative analysis of the changes in the MP physicochemical characteristics after the pretreatments indicated that polyamide (PA) and PET are not resistant to acid and alkali treatment, respectively. Principal component analysis shows that the effect of pretreatments on the MPs follows a decreasing sequence: alkali > high concentration of acids > low concentration of acids > HO and Fenton. Additionally, the susceptibility of the MPs to the pretreatments follows a decreasing sequence: PET, PA and polymethyl methacrylate (PMMA) > polystyrene (PS) > polyethylene (PE) and polypropylene (PP). The findings supply novel insights into the effect of chemical pretreatments on MP extraction in sewage sludge.
Sign in to start a discussion.
More Papers Like This
Pretreatment methods for the isolation of microplastics from wastewater and sludge samples: Part 1
This article reviews pretreatment methods used to isolate microplastics from wastewater and sludge samples, covering the first part of a multi-part technical overview published in a Polish engineering journal. The review addresses the procedural steps required to separate microplastic particles from complex environmental matrices prior to identification and quantification.
Optimised reduction of total solids and organic matter of sewage sludge matrix for an improved extraction of microplastics
Researchers optimized chemical digestion protocols for extracting microplastics from sewage sludge, finding that maximizing reduction of total solids and organic carbon content significantly improved the reliability and efficiency of subsequent density-based microplastic separation.
Optimization of a method used for extracting microplastics from an organic matter-rich matrix and isolated particles assessment
Researchers optimized a method for extracting microplastics from sewage sludge — a challenging organic-rich matrix — by combining density separation and chemical digestion steps, improving recovery rates and enabling more accurate characterization of sludge-associated microplastics.
Pretreatment methods for the isolation of microplastics from wastewater and sludge samples Part 2
This article reviews pretreatment methods for isolating microplastics from wastewater and sludge samples, examining digestion, density separation, and filtration approaches to optimize sample preparation for downstream identification and quantification.
A novel method for organic matter removal from samples containing microplastics
Researchers developed a novel organic matter removal method for wastewater treatment plant sludge samples containing microplastics, demonstrating that the approach is more time- and cost-effective than existing techniques while preserving microplastic integrity for accurate quantification and identification.