Paint Sludge Research Articles

Chemical looping gasification of automotive paint sludge with red mud oxygen carrier for flammable gas production

Automotive paint sludge (APS) is a hazardous waste with many harmful substances, which should be properly disposed and managed. Red mud (RM) is a solid waste generated during the production of alumina industry, of which the components are highly similar to the components of synthetic iron-based oxygen carriers. In this study, RM was used as an oxygen carrier (OC) for chemical looping gasification(CLG) of APS to produce flammable gas (H2, CH4 and CO). The effects of different reaction conditions on the production of flammable gas were explored. Among them, the red mud oxygen carrier addition ratio plays a decisive role in the production of CH4, CO and H2. The reaction temperature determines the percentage of CH4 in the flammable gas. Meanwhile, the experimental reaction mechanism was further elaborated. The lattice oxygen in the Fe2O3 of RM-OC can migrate to form reactive oxygen (ROS). In the presence of ROS, the hydrocarbons react to produce large amounts of CH4, while CH4 is cracked to produce large amounts of H2 and CO. This study can provide theoretical basis for the comprehensive utilization of APS and RM, which is of great practical significance for protecting the ecological environment.

Microwave Pyrolysis of Automotive Polypropylene Based on a Microwave Atmosphere Tube Furnace

Plastics have light weight and excellent performance, which are widely used in all kinds of automobiles. Polypropylene (PP) and its reinforcing materials are used in automotive components, where the surfaces of bumpers and fenders are coated with paint. Traditional recycling can frequently generate various pollutants, such as paint sludge. Microwave pyrolysis is a more environmentally friendly pyrolysis method with a higher heating coefficient than traditional electric pyrolysis. This study first explores the elemental composition of two types of automotive PP plastics and uses thermo-gravimetric analysis and the Kissinger-Akahira-Sunose method to preliminarily calculate the activation energy of automotive PP. The calculation results show that the activation energy of PP containing paint ranges from 189.145 kJ/mol- 199.513 kJ/mol, with an average value of 193.903 kJ/mol. The activation energy of PP without paint is between 215.506 kJ/mol-265.794 kJ/mol, with an average value of 242.425kJ/mol. Then, pyrolysis experiments on PP for vehicles without paint are conducted using a microwave atmosphere tube furnace at different temperatures and microwave powers. The experimental results showed that, when the pyrolysis temperature increased from 500oC to 620 oC, the total proportion of gas products rose from 0.75 wt.% to 4.81 wt.%, and the content of alkanes in the liquid products improved from 26.21 wt.% to 34.37 wt.%; when the microwave power increased from 900 W to 1100 W, the gas product rose to 20.77 wt.%, and the content of aromatic compounds in the liquid product improved to 17.78 wt.%. In addition, the pyrolysis experiment of automotive PP containing paint showed that paint had a relatively minor effect on the pyrolysis products of automotive PP. This study shows that using microwave pyrolysis to treat automotive PP and PP with paint is feasible, which provides a reference for the clean treatment of automotive polymers.

Co-pyrolysis of Sewage Sludge with Paint Sludge: Kinetics and Thermodynamic Analysis via Iso-conversional Methods

Co-pyrolysis of Sewage Sludge with Paint Sludge: Kinetics and Thermodynamic Analysis via Iso-conversional Methods

Management of water-based paint sludge originating from the automotive industry via composting

ABSTRACT Water-based paint sludge generated from the automotive industry is considered a hazardous waste due to its high carbon content and is challenging and costly to manage. This study investigates the management of water-based paint sludge through the composting process, considering its high carbon content. The water-based paint sludge was composted in five separate reactors with the addition of treatment sludge from the same industry as co-substrate and inoculum, as well as sunflower stalks as a bulking agent. The ratio of paint sludge added to the compost mixtures varied between 40% and 80%. The highest temperature was achieved in reactors where industrial sludge was added, and the bulking agent was used at a rate of 20% (R3 and R5). The most efficient composting process was conducted with the addition of 60% water-based paint sludge, 20% treatment sludge, and 20% sunflower stalks (w/w, wet weight basis) (R3). During this process, reductions in organic matter content were observed due to organic matter mineralization, resulting in a decrease in moisture during the maturation phase and consequently reducing waste volumes. The composting process can be a useful tool in addressing the challenges of paint sludge management. Utilizing the composting process not only reduces waste volumes, thereby minimizing environmental impacts, but also offers a sustainable approach to paint sludge management by lowering disposal costs. It is also possible to achieve more effective results by composting paint sludge with different recipes and the use of various bulking agents. Implications Composting is a method that can be used to achieve stabilization, reduce the quantity, and enable biodrying of water-based paint sludge generated from the automotive industry. In this study, different ratios of paint sludge were mixed with treatment sludge from the same industry as co-substrate and inoculum, while sunflower stalks were added as a bulking agent, and a composting process was conducted. The addition of industrial wastewater treatment sludge and sunflower stalks has increased the efficiency of the paint sludge composting process. In the management of paint sludge, the composting process has emerged as a significant alternative that reduces disposal costs and environmental impacts.

Paint sludge derived activated carbon encapsulating with cobalt nanoparticles for non-radical activation of peroxymonosulfate

Industrial solid waste management and recycling are important to environmental sustainability. In this study, cobalt (Co) nanoparticles encapsulated in paint sludge-derived activated carbon (AC) were fabricated. The Co-AC possessed high conductivity, magnetic properties and abundant metal oxide impurities (TiAlSiOx), which was applied as multifunctional catalyst for peroxymonosulfate (PMS) activation. Compared to pure AC, the Co-AC exhibited significant enhanced performance for degradation of tetracycline hydrochloride (TCH) via PMS activation. Mechanism studies by in situ Raman spectroscopy, Fourier infrared spectroscopy, electrochemical analysis and electron paramagnetic resonance suggested that surface-bonded PMS (PMS*) and singlet oxygen (1O2) are the dominant reactive species for TCH oxidation. The non-radical species can efficiently oxidize electron-rich pollutants with high efficiency, which minimized the consumption of PMS and the catalyst. The removal percentages of TCH reached 97 % within 5 min and ∼ 99 % within 15 min in the Co-AC/PMS system. The Co active sites facilitated PMS adsorption to form the PMS* and the TiAlSiOx impurities provided abundant oxygen vacancy for generation of the 1O2. In addition, the Co-AC/PMS system achieved high efficiency and stability for oxidation of the target pollutants over a long-term continuous operation. This work not only offers a cost-effective approach for recycling industrial waste but also provides new insights into the application of waste-derived catalyst for environmental remediation.

Strength and environmental evaluation of building bricks using industrial waste for liveable environments

Researchers around the world have been enthusiastically using industrial waste to develop eco-friendly building materials. The main objective of this study was to explore the potential of using local industrial waste, such as Solid Waste Fly Ash (SWFA) and Paint Sludge (PS), as alternative to non-renewable laterite soil. During the preliminary stage, compacted cylinders of two systems were investigated: Laterite Soil (LS) and SWFA at 50:50 ratio, and a combination of LS, SWFA and PS (LSP) at 50:25:25 ratio. Traditional stabilisers Hydrated Lime (HL) and Ordinary Portland Cement (OPC), as well as Ground Granulated Blastfurnace Slag (GGBS), were used at different ratios (10%, 20%, 30% and 40%) for these cylinders. The cylinders were cured for 7, 28 and 60 days prior to strength and water absorption test. The results showed that 30% stabiliser dosage provided the best strength and economic benefits. Based on these findings, pilot industrial and commercial trials were conducted using full-sized unfired bricks. The LSP brick system with the blended stabiliser HL-GGBS performed exceptionally well in terms of engineering properties. The investigation suggests that SWFA and Paint Sludge can be promising substitutes for clay in unfired bricks production, promoting waste recycling and reducing the impact of landfills. Using local available waste materials to manufacture unfired bricks present a viable alternative to fired bricks, especially in low-load bearing situations. This research contributes to innovation, enhanced waste management, and the concept of green building. Moreover, it minimizes energy usage and hazardous emissions associated with brick firing, aligning with the Sustainable Development Goals (SDGs).

Enhancing anaerobic digestion of automotive paint sludge through biochar addition

The reduction of traditional fuel sources and the unpredictability of the global economy have led to a push for renewable energy alternatives. Waste recycling can significantly reduce greenhouse gas emissions. In this study, the effects of different proportions of biochar on the efficiency of mesophilic anaerobic digestion of automotive paint sludge were investigated over a period of one month. A combination of paint sludge and anaerobic sludge in a ratio of three to one was used, and biochar was added to the anaerobic digestion reactor in two different amounts of 10 and 26 g/l, with a control sample without biochar. The cumulative volume of biogas produced at the end of the one-month experiment was recorded for three samples: the control sample (without biochar), the second sample (with 2 g of biochar), and the third sample (with 5.2 g of biochar). The volumes of biogas produced were 300, 380, and 530 ml, respectively. Additionally, the COD reduction rates were 25%, 33%, and 48%, and the VS decrement rates were 21%, 27%, and 43%, respectively. The findings showed that adding biochar to the anaerobic digestion reactor containing automotive paint sludge increased biogas production. Additionally, gas chromatography results for an optimal sample of biogas extracted from the anaerobic digestion reactor indicated the presence of about 50% methane gas. These results highlight the potential for utilizing biochar in anaerobic digestion processes to improve renewable energy production and waste management.

Automotive Paint Sludge: A Review of Pretreatments and Recovery Options

Automotive paint sludge (PS) is the waste product generated in the painting process of vehicle bodies. Although automotive spray painting is an automated operation, its efficiency is still quite low, since approximately 40–50% of the employed paint does not reach the target and, after being mixed with the collecting water, becomes PS. PS is a very complex material that contains several organic and inorganic components, in addition to 90% water immediately after production. Italian automotive factories produce from 2.5 to 5.0 kg of PS per painted car. If that figure is related to the number of vehicles produced worldwide every year, in the order of 100 million, it determines an annual PS amount in the order of 200,000–500,000 t. Consequently, a proper final destination for PS must be found. The waste management hierarchy and the principles of the circular economy require that we privilege solutions that foresee the recovery of valuable products or energy. This paper first reviews the processes and the machines that have been recently developed to obtain an enhanced mechanical dewatering of PS. The pretreatment of PS dewatering is often crucial in order to obtain high efficiency in the subsequent recovery process. Afterwards, the paper presents and discusses the recovery options that have been proposed and tested, at different scales, by several authors in the last thirty years. The processes for PS management can be grouped as follows: (i) direct employment of physically/chemically treated PS in the production of primers and sealants; (ii) utilization of PS for the production of building materials, as supplementary components of cement concrete, mortar, or bituminous mixtures; (iii) extraction of valuable organic and inorganic products by using thermal processes (pyrolysis, gasification); (iv) biological processes for PS detoxification, metal recovery, and stabilization before landfilling.

The feasibility study of stabilizing the automotive paint sludge by recycling, to produce green concrete blocks, considering environmental and mechanical factors

The feasibility study of stabilizing the automotive paint sludge by recycling, to produce green concrete blocks, considering environmental and mechanical factors

Pyrolytic kinetics, reaction mechanisms and gas emissions of waste automotive paint sludge via TG-FTIR and Py-GC/MS

The present study experimentally quantified the pyrolysis behaviors of waste solvent-based automotive paint sludge (OAPS) and water-based automotive paint sludge (WAPS) at four different heating rates using thermogravimetric-Fourier transform infrared (TG-FTIR) spectrometry and pyrolysis-gas chromatography-mass (Py-GC/MS) spectrometry analyses. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods combined with the master-plots method were employed to investigate the pyrolysis kinetics and reaction mechanisms of waste automotive paint sludge. Three reaction stages and three reaction peaks in stage 2 were distinguished for both OAPS and WAPS degradation. The average activation energy (Ea) estimates for OAPS (FWO: 179.09 kJ/mol; KAS: 168.28 kJ/mol) were slightly higher than WAPS (FWO: 175.90 kJ/mol; KAS: 164.80 kJ/mol) according to FWO and KAS methods. The main pyrolysis reaction mechanisms of both OAPS and WAPS closely matched with the order-based model corresponding to 3rd and 2nd order random nucleation on an individual particle. The evolved gas species of CH4, CO2, phenols, NH3, H2O, and CO from OAPS and WAPS pyrolysis were identified by TG-FTIR. According to Py-GC/MS, hydrocarbons (47.2%) and O-components (42.7%) were relatively large after OAPS and WAPS pyrolysis, respectively. Melamine was the most abundant N-component product after pyrolysis of OAPS (5.8%) and WAPS (4.8%).

Using Automotive Paint Sludge as a Binder for Pelletizing Magnetite Ore

Using Automotive Paint Sludge as a Binder for Pelletizing Magnetite Ore

Characterizing the emission behaviors of cumulative VOCs from automotive solvent-based paint sludge.

Volatile organic compounds (VOCs) diffused from paint sludge are potential hazard contributing significantly to environmental pollution and exposure to them can cause severe health issues. In this paper, a diffusion-controlled model was firstly developed for characterizing the emission behaviors of cumulative VOCs from automotive solvent-based paint sludge based on the worst field management scenario. The presented model is characterized by two key parameters: the diffusion coefficient (Dm) and the initial emittable concentration (Cm,0), which can be simultaneously obtained by our proposed ER-history method. Four major components were detected including 1-butanol, butyl acetate and 1,2,4-trimethylbenzene and 1-ethyl-4-methylbenzene. In addition, the model was validated by using environmental data in a ventilated test chamber, proving that the model is reliable and convincing. However, relative deviations of 1-butanol and butyl acetate are larger than those of 1,2,4-trimethylbenzene and 1-ethyl-4-methylbenzene, indicating that the model is more accurate for predicting hydrophobic VOCs release than those of hydrophilic VOCs. Besides, an increase in Cm,0 and Dm tends to enhance VOCs cumulation release. Our studies provide new insight into experimental designs for rapid model parameters measurement and a sound basis for estimating VOCs cumulative release from paint sludge as well as for hazardous waste.

Feasibility of sludge generated in water-based paint industries as cement replacement material

An estimated 2100 tonnes of solid sludge is generated per annum from the water-based paint industries of Bangladesh. This paint sludge (PS) is usually incinerated, consuming energy and generating greenhouse gases and other pollutants. Through chemical analysis and standardized tests, it was shown that PS contains a similar array of oxides as Ordinary Portland Cement (OPC) and has pozzolanic characteristics. Considering these, PS was examined as a cement replacement material to create an alternative and economically beneficial way of disposing of this waste. Cement paste and mortar samples were prepared by replacing 5%, 10%, 15%, 20% and 30% of OPC with PS. To assess mechanical and durability properties of PS-incorporated samples, different tests were carried out that included consistency, setting time, compressive strength, soundness, sulfate attack, alkali silicate reactivity and chloride diffusion. Both initial and final setting times of PS-incorporated cement increased with an increase in PS fraction but remained within the standard limit. Compressive strength increased for 5% PS replacement but decreased with further increase in PS replacement compared to 100% OPC mortar. A slightly higher rate of compressive strength gain was observed at later ages for PS-incorporated cement than 100% OPC, which confirmed the pozzolanic characteristic of PS. The addition of PS was found to reduce the expansion of mortar bars in both soundness and ASR tests. It also inhibited ettringite crystal formation in the mortar matrix for sulfate exposure. Initially, chloride permeability increased in the early days for PS-incorporated mortar but was found to decrease rapidly at later ages. Altogether, it may be concluded that a 15% replacement of OPC with PS would comply with the necessary strength and durability standards.

Degradation of paint and textile industrial effluents by indigenous bacterial isolates

Untreated paint and textile effluents discharged from industries cause serious environmental threats to fauna and flora. This study thus, investigated the potential of different indigenous bacterial cells for the degradation of paint and textile effluents. Paint and textile effluents samples were aseptically collected from paint and textile industries. Physical, chemical, heavy metals properties and microbial load of the effluent were investigated using standard methods. Enrichment, Isolation and identification of bacterial isolates were determined using the standard microbiological methods. Screening of paint and textile effluents degraders was carried out using solid phase screening method. Degradation of paint and textile effluents were determined by Fourier-transform infrared (FTIR) analysis and spectrophotometrically. Results revealed that among the heavy metals analyzed, lead from paint effluent had highest value of 5.49 ± 1.2 mg/L. All the samples collected were turbid with highest and lowest values of 865 ± 1.3 and 514 ± 2.5 (NTU) from paint effluent samples. Paint effluent also recorded highest bacterial count of 6.85 ± 1.13 CFU/ml while paint sludge had the lowest count of 1.16 ± 0. 15 CFU/g. Forty-seven bacterial isolates were obtained from the paint and textile effluents samples. Screening of the 47 isolates showed that 21 isolates possessed the ability to grow on agar plates amended with paints and textile dyes. Out of the 21 positive isolates, 12 isolates were obtained from paint samples while nine isolates were recovered from the textile samples. Highest degradation activity was recorded by Bacillus subtilis (94.37% ±5.35) obtained from textile effluent sample while Micrococcus sp (46.55% ±8.30) from paint polluted soil sample had the lowest degradation activity. FTIR analysis showed the transformation and disappearance of peaks in the treated paint and textile effluents by Bacillus subtilis. This study revealed the ability and effectiveness of Bacillus subtilis in the removal of toxic materials in paint and textile effluents, thus could be applied for industrial use.

Comprehensive understanding the emission characteristics and kinetics of VOCs from automotive waste paint sludge in a environmental test chamber

• Present the first study on emission characteristics and kinetics of VOCs from automotive waste paint sludge. • Internal diffusion-controlled mechanism is dominant during the whole emission period. • Oxygenated compounds are more easier to diffuse than aromatic hydrocarbons from paint sludge to air. • Oil-based wet paint sludge has higher TVOC and longer emission than others. • The first-order kinetic equation is suitable for describing the emission mass flux of VOCs and TVOC.

Characterization and evaluation of dried automotive paint sludge as cement-based composite

Automotive industries generate large amount of paint sludge where 40% of paint sprayed on the car’s body end up as waste. Inappropriate paint sludge disposal is hazardous to public health and environment. An approach to use paint sludge into composite materials was conducted with purpose to recycle this waste into valuable concrete product. Automotive paint sludge (APS) was obtained from one of the car manufacturers in Malaysia. Chemical composition and physical properties of dried APS was characterized using Fourier Transform-Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and X-Ray Fluorescence Spectroscopy (XRF) prior to preparation of composite formulation. Mechanical properties i.e. compressive strength of composite-based cement after being substituted with the drie APS was conducted with increment percentage of 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt%. Cement to water to admixture with density ratio of 1000:200:16 kg/m 3 respectively were used for all the blended cement paste mixtures. Characterization of the dried APS shows that chemical compounds are suitable for cement formulation. Results indicated that both control specimen and dried APS composite-cement increase the compressive strength with increasing curing days. However, the results show that blended cement with dried APS has lower overall compressive strength compared to conventional cement paste that may due to the porosity of the formed capillary structure.

The Role of Logistics in Industrial Side Stream Utilisation – Case: Aqueous Paint Sludge

Purpose: In this article, the utilisation of a case side stream, aqueous paint sludge is studied in accordance with the principles of the circular economy. The study's main objective is to find new potential utilisation possibilities for aqueous paint sludge generated in the region and take a closer look at the role of logistics in the industrial side stream utilisation-based business cases and value chains. Study design/methodology/approach: In this article, the utilisation of aqueous paint sludge is studied via a descriptive case study in the context of Northern Ostrobothnia, Finland. The current state of the paint sludge problem was analysed by interviewing five company representatives. In addition, a workshop was organised, and before the workshop, a questionnaire was sent to all invited. Findings: As a result, the most feasible solutions for aqueous paint sludge utilisation were identified and evaluated from economic, technical, and environmental points of view in the context of this study. In all the proposed solutions, one general challenge was the logistics for narrow material flows from decentralised sources in a relatively large geographical area. Originality/value: Prior case studies of paint sludge utilisation as a raw material have been conducted, but the logistics have not played a significant role in the studies. Logistics has been an important part of the circular economy in the literature. This study reaffirms this notion and finds logistics to have an important and decisive role in industrial side stream utilisation-based business cases and value chains.

An Experimental Study on Thermal Properties of Sustainable Bricks Made from Local Industrial Waste

Rapid development around the globe, increase of population and construction with the latest and megastructures have escalated the demand for energy. The increasing of ambient outdoor temperature requires mechanical air conditioners to maintain a comfortable environment within the building, this contributes to high energy consumption. Building with good thermal conductivity properties passively reduces energy consumption. This experimental work focuses on four (4) brick systems which are Laterite Clay (LC), Solid Waste Fly Ash (SWFA) Bricks, Laterite SWFA (LS) Brick, and Laterite SWFA Paint Sludge (LSP) Bricks. Ordinary Portland Cement (OPC), Hydrate Lime (HL), and Ground Granulated Blast Furnace Slag (GGBS) were used as stabiliser. Higher thermal conductivity was recorded for all bricks systems that stabilised with HL. Thermal conductivity was significantly reduced when GGBS was incorporated as a blended stabiliser. SWFA bricks system recorded the lowest thermal conductivity of all bricks systems investigated. A lower thermal conductivity value indicates better thermal properties. In all brick-wall systems, the thermal conductivity was found to increase linearly with density.

Optimization of zinc bioleaching from paint sludge using Acidithiobacillus thiooxidans based on response surface methodology

The reduction of zinc metal in the paint sludge, a hazardous waste, was investigated using Acidithiobacillus thiooxidans by a two-stage bioleaching process. This process was performed using the response surface methodology (RSM) method based on the central composite design (CCD). Four variables, a temperature range of 32–34.5–37 °C, rotation speed of shaker 120–160–180 rpm, pH of 4.2–3.2–2.2, and particle sizes of 1–2–3 mm, were used to optimize the experiments. The results showed that with a constant pulp density of 10 g/L at 32 °C, shaker speed of 120 rpm, a particle size of 1 mm and pH of 4.2, the highest removal predicted by the software (Design Expert version 11) was 22.89%. Repeating the experiments confirmed a decrease in zinc to the nearest predicted point. According to the ANOVA result, the rotation speed of the shaker has the greatest effect on the bioleaching process, followed by the two variables of the rotation speed of shaker and pH together affects. After the bioleaching process, energy dispersive X-ray (EDX) and mapping analysis showed quantitative changes in the chemical composition of the paint sludge, and morphological changes of texture were confirmed by scanning electron microscopy (SEM).

Zn bio extraction from a zinc rich paint sludge by indigenous Pseudomonas aeruginosa

Paint sludge is considered hazardous waste due to its heavy metals and high organic compounds. Incineration and landfilling are the methods of disposing of sludge collected from the paint spray of an automotive factory in Iran. Pseudomonas aeruginosa was isolated from water-based paint sludge using Bushnell-Haas medium and identified by chemical and molecular methods. A two-step bioleaching experiment using the Response surface methodology was used to investigated P. aeruginosa to mobilize the contaminant zinc metal from the paint sludge. Variables included temperatures from 32 to 37 °C, the rotation speed of shaker from 120 to 180 rpm, particle sizes from 1 to 3 mm, and bacteria were adapted to a pulp density of 7 g/L. When the bioleaching process was optimized at pH 7, temperature 32 °C, particle size 3 mm, and 180 rpm, the concentration of zinc decreased to 28.71%. A decrease in zinc of 27% was confirmed by repeating the experiment three times. The ANOVA test confirmed the most effective parameters were temperature and particle size. The most efficient process to remove zinc was achieved as a result of the effect between temperature and pH.