0
Article Tier 2 Detection Methods Sign in to save

Co-pyrolysis of sewage sludge and metal-free/metal-loaded polyvinyl chloride (PVC) microplastics improved biochar properties and reduced environmental risk of heavy metals

Environmental Pollution 2022 45 citations

AI summary Read the abstract

Sewage sludge was co-pyrolyzed with metal-laden and metal-free PVC microplastics, producing biochars with improved properties and reduced environmental risk from heavy metals compared to pyrolyzing sludge alone. The study demonstrates co-pyrolysis as a strategy to address both plastic and heavy metal pollution in sludge treatment processes.

Polymers

Co-pyrolysis of sewage sludge and plastics have been utilized for producing biochars as a strategy to fix plastic pollution. However, comparative studies on the characteristics and environmental risk of heavy metals in biochars obtained by the co-pyrolysis of sludge and microplastic with/without metal additives are seldom. Here we demonstrated the effects of simulated co-pyrolysis (at 400 °C) of sewage sludge and metal-free or metal-loaded polyvinyl chloride (PVC) microplastics at different mass ratios (1:0, 19:1, 3:1, 1:3, sewage sludge: PVC (w/w)) respectively. Results revealed that co-pyrolysis of metal-loaded PVC and sewage sludge resulted in higher electrical conductivity, ash content, and an acidic pH of biochars as compared to the co-pyrolysis of metal-free PVC and sewage sludge. Addition of metal-loaded PVC increased total concentrations of calcium (Ca), magnesium (Mg), cadmium (Cd), and lead (Pb) in biochars, but reduced the bioavailability of Cd, chromium (Cr), nickel (Ni), and zinc (Zn) in biochars. Analysis of chemical speciation showed that heavy metals (except Pb) in biochars derived from co-pyrolysis of sewage sludge and metal-loaded PVC had higher percentage of more stable fraction (residual fraction) and lower potential ecological risk index (RI) value. S1AP3 (sludge: metal-loaded PVC = 1:3) biochar had the lowest environmental risk based on RI value (14.41). To sum up the present study suggests that the addition of metal-loaded PVC microplastic in sewage sludge had a positive impact on the immobilization of heavy metals during co-pyrolysis process.

More Papers Like This

Article Tier 2

The fate and mobility of chromium, arsenic and zinc in municipal sewage sludge during the co-pyrolysis process with organic and inorganic chlorides

AI summary Read the abstract

Researchers co-processed sewage sludge with PVC plastic and iron chloride at different temperatures to study how these additives stabilize toxic heavy metals (arsenic, chromium, zinc) in the resulting biochar. PVC at 600°C was most effective at reducing arsenic and zinc hazards, while iron chloride better stabilized chromium, offering tailored strategies for safer sludge disposal.

Article Tier 2

Pyrolysis-induced migration and transformation of heavy metals in sewage sludge containing microplastics

AI summary Read the abstract

Researchers studied how the presence of PVC and PET microplastics affects the behavior of heavy metals during sewage sludge pyrolysis. They found that microplastic addition influenced the migration and chemical transformation of metals like chromium, copper, and zinc during heating, with effects varying by plastic type and concentration. The study suggests that microplastic contamination in sewage sludge should be considered when designing pyrolysis processes for sludge recycling.

Article Tier 2

How microplastics affect sludge pyrolysis behavior: Thermogravimetry-mass spectrum analysis and biochar characteristics

AI summary Read the abstract

Microplastics in sewage sludge alter how the sludge burns during pyrolysis: PVC microplastics sped up decomposition while polyethylene and polypropylene slowed it down. This matters because sewage sludge from wastewater plants contains thousands of microplastic particles per kilogram, and understanding how they change the energy recovery and byproduct quality of sludge treatment helps improve the management of this widespread microplastic sink.

Article Tier 2

Sludge-derived biochar: Physicochemical characteristics for environmental remediation

AI summary Read the abstract

This review examines how sewage sludge can be converted into biochar, a carbon-rich material useful for cleaning up environmental contaminants including microplastics and heavy metals from water and soil. The process turns a waste product into an effective pollution filter while reducing the volume of sludge that needs disposal. This approach is relevant to microplastics research because biochar could help remove plastic particles from contaminated water and agricultural land.

Article Tier 2

Pyrolysis behavior of sewage sludge coexisted with microplastics: Kinetics, mechanism, and product characteristics

AI summary Read the abstract

Researchers investigated the co-pyrolysis behavior of sewage sludge mixed with polyethylene and polylactic acid microplastics. They found that the presence of microplastics improved the overall pyrolysis performance and altered the composition of the resulting bio-oil and gas products. The study suggests that understanding how microplastics in sewage sludge affect thermal treatment could help optimize waste processing at wastewater treatment plants.

Research digests by email

When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.

Email me about

Share this paper