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The non-biodegradable Congo red (CR) dye which is widely used in textile industries has poses carcinogenic risks due to its complex reactions that may generate benzidine. Effective treatment of industrial effluent containing CR dye is imperative. This study assessed chitosan (Cs) and chitosan/fly ash (Cs/Fa) composites for biosorbing CR dye from synthetic textile wastewater. Fly ash varied in the range of (1:0.25–1:1) with chitosan to assess adsorption performance. Characterization techniques included FTIR, SEM, EDX, BET, and zeta potential analyses. Response surface methodology guided the determination of optimal variables. The study examined Cs and Cs/Fa dosage (A), time (B), and initial dye concentration (C) effects on CR removal. Incorporating fly ash substantially cut adsorption costs by 50% while enhancing dye removal up to 85% at pH 6. Improved acidic stability of chitosan (Cs/Fa 1:0.75) was notable. Chitosan (Cs) exhibited a high Congo red removal efficiency of 98% while the chitosan/fly ash (Cs/Fa) composites showed a substantial removal efficiency of 94%. Optimal conditions were 2 g L−1 of adsorbents, initial CR concentration of 40 mg L−1 for 120 min. Freundlich isotherm model best described adsorption behavior. Pseudo-second-order kinetics correlated significantly (R2 = 0.999). This study showed the potential of Cs and Cs/Fa bio-composites for effective textile wastewater treatment. [ABSTRACT FROM AUTHOR]

Expansive clays feature high compressibility and large swelling-shrinkage potential, which may cause significant damage to the infrastructures, including pavements. This study investigates the potential use of industrial waste ash generated from municipal solid waste incineration (MSWI) as a more sustainable treatment method to treat expansive soils compared to the use of conventional coal fly ash. A series of tests was conducted to study the mechanical, durability, and environmental performance of the MSWI fly ash in comparison with the coal fly ash. The study reveals that the compressive strength and resilient modulus of 20% MSWI fly ash treated sample increased to 0.86 MPa and 213 MPa respectively, depicting an increase of 150% and 240% of the control clay specimen. Results also indicate that MSWI treated expansive clay shows better performance during the soaked California bearing ratio (CBR) testings, moisture susceptibility and cyclic wetting–drying tests compared to coal fly ash treated samples. Microlevel investigations reveal that the influence of cation exchange is more decisive in the MSWI-treated clays due to the presence of higher Ca2+ ions, during the early stages, and the influence of hydration is stronger at the later stage of stabilisation. X-ray diffraction (XRD) results show that gismondine, albite, calcite, portlandite, andradite, and ettringite are the main crystalline phases formed during the stabilization. Heavy metal concentrations after the stabilisation are within the allowable limit defined by state regulations. Applying MSWI fly ash as a ground treatment for expansive clays can reduce the consumption of natural resources, promoting a "zero landfill" policy. [ABSTRACT FROM AUTHOR]

The current study examines the strength and transport properties of reclaimed asphalt pavement (RAP) inclusive pervious concrete (PC) pavement mixes containing various industrial and agricultural wastes such as silica fume (SF), fly ash (FA), and bagasse ash (BGA). Apart from a conventional PC mix (containing natural aggregates) and a 100% RAP inclusive PC mix, seven different mixes were developed by mixing 100% RAP aggregates with SF (5 and 10%), FA (10 and 15%), and BGA (5, 10, and 15%) as partial replacements for ordinary Portland cement. The above-mentioned PC pavement mixes were investigated for density, porosity, permeability, compressive strength, modulus of rupture, and abrasion resistance. The interconnected pore structure of conventional PC and RAP-PC pavement mixes was investigated using 2D image analysis and X-Ray microcomputed tomography. Based on the laboratory results, it can be stated that the inclusion of RAP significantly improves the transport properties of PC pavement mixes with increased porosity and permeability values. This was primarily due to a more interconnected pore matrix and lesser isolated voids in the RAP-PC pavement mix. The addition of SF could only improve the strength parameters (compressive strength and modulus of rupture) of the RAP-PC pavement mix. In contrast, BGA inclusion was observed to improve its transport properties (porosity and permeability). Furthermore, the inclusion of SF, FA, and BGA in a 100% RAP-PC mix improved abrasion resistance. When compared to the conventional PC pavement mix, incorporating RAP aggregates blended with SF, FA, and BGA can reduce the production cost of 1 m3 PC by 30–61% and lower CO2 emissions by 13–21%. However, considering the strength and transport property requirements of PC mixes, as well as the economic and environmental viability, the present investigation recommends using 5% SF, 10% FA, and 10% BGA in a 100% RAP-PC pavement mix. [ABSTRACT FROM AUTHOR]

Due to industrialization, soil heavy metal pollution is a growing concern, with humic substances (HS) playing a pivotal role in soil passivation. To address the long duration of the compost humification problem, coal fly ash (CFA) in situ catalyzes the rapid pyrolysis of the cotton stalk (CS) to produce HS to address Cd passivation. Results indicate that the highest yield of humic acid (HA) (8.42%) and fulvic acid (FA) (1.36%) is obtained when the CS to CFA mass ratio is 1:0.5, at 275 ℃ for 120 min. Further study reveals that CFA catalysis CS humification, through the creation of alkaline pyrolysis conditions, Fe2O3 can stimulate the protein and the decomposition of hemicellulose in CS, and then, through the Maillard and Sugar-amine condensation reaction synthesis HA and FA. Applying HS-CS&CFA in Cd-contaminated soil demonstrates a 26.69% reduction in exchangeable Cd within 30 days by chemical complexation. Excellent maize growth effects and environmental benefits of HS products are the prerequisites for subsequent engineering applications. Similar industrial solid wastes, such as steel slag and red mud, rich in Fe2O3, can be explored to identify their catalytic humification effect. It could provide a novel and effective way for industrial solid wastes to be recycled for biomass humification and widely applied in remediating Cd-contaminated agricultural soil. [ABSTRACT FROM AUTHOR]

Cold mix asphalt (CMA) technology is the most sustainable technology (green) available for the construction of flexible pavement to date, owing to the lower production temperatures involved. The present research investigates different fillers such as cement, fly ash (FA), and Stabil-road (SR) in different proportions ranging from 0 to 3% (1% increment). One control CMA with 1.5% water content and 6.6%asphalt residue and nine mixes with variable filler contents were prepared and tested according to the standards. The prepared mixes were tested and analyzed for mechanical properties namely Marshall stability, indirect tensile strength, resilient modulus (Mr), and abrasion loss. The stability of the CMA with 3% cement was 22% higher compared to the control CMA. Improvements in strength were observed with the inclusion of filler in the cold mix. The cold mix bituminous macadam (CMBM) is used for low-volume roads with mineral fillers, and it is a type of CMA, but using FA and SR, the strength and workability of the CMBM mix can be improved, and the mineral filler can be replaced by industrial waste. Significant reductions in production temperature and improved service life are some of the study's outcomes. It is a significant study because it reduces the asphalt production temperature and increases the pavement service life. It reduces energy loss during the construction of road pavement. Furthermore, the mechanical properties of the designed CMA depend on the mixing of aggregates, prewetting water content, emulsion, curing time, and pulse repetition periods. [ABSTRACT FROM AUTHOR]

The environmental impact of wastewater discharged from the textile dyeing industry has a significant challenge and influence on aquatic ecosystems and human health if not properly managed. This study aimed to develop a novel cross-linked chitosan composite, denoted as chitosan/fly ash/polyvinyl alcohol (Ch/FA/PVA), as a bio-adsorbent for removing Congo Red (CR) textile dye from industrial wastewater. The synthesis involved the incorporation of FA into the chitosan matrix at various ratios to optimize the process. A specifically tailored composite, Ch/FA0.75/PVA, exhibited superior performance with a remarkable 99.7% CR removal under optimum conditions: adsorbent dose (0.9 g/l), contact time (50 min), and dye concentration (40 mg/l). The characterization of Ch/FA0.75/PVA through SEM–EDX, BET, FTIR, and pHzpc confirmed its suitability for adsorption. Employing Box–Behnken design and analysis of variance (ANOVA) facilitated the optimization of key adsorption variables. The Freundlich model described the adsorption equilibrium, indicating a maximum adsorption capacity of 263.15 mg/g for CR dye. The pseudo-second-order model demonstrated favorable kinetics. The study was scaled up to the practical application of Ch/FA0.75/PVA in a pilot plant for industrial wastewater treatment, revealing substantial removal percentages for dye, color, COD, BOD5 and TDS. This comprehensive approach highlights the promising efficacy of Ch/FA0.75/PVA in addressing environmental concerns associated with textile dye wastewater. [ABSTRACT FROM AUTHOR]

CO2 mineralization plays a critical role in the storage and utilization of CO2. Coal fly ash (CFA) and red mud (RM) are widely utilized as CO2 mineralizers. However, the inert calcium species in CFA limit its carbonation capacity, meanwhile the substantial Ca2+ releasing of RM is hindered by a covering layer of calcium carbonate. In this study, CO2 mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity. Multiple analyzers were employed to characterize the raw materials and resulting mineralization products. The results demonstrated that a synergistic effect existed in the composite system of CFA and RM, resulting in improving CO2 mineralization rate and efficiency. The produced calcium carbonate was ectopically attached the surface of CFA in the composite system, thus slowing down its coverage on the surface of RM. This phenomenon facilitated further releasing Ca2+ from the internal RM, thereby enhancing CO2 mineralization efficiency. Meanwhile, the inclusion of RM significantly improved the alkalinity of the composite system, which not only promoted the dissolution of Ca2+ of the inert CaSO4(H2O)2 in CFA, but also accelerated CO2 mineralization rate. The investigation would be beneficial to CO2 mineralization using industrial solid wastes. [ABSTRACT FROM AUTHOR]

The pre-eminence of concrete as the constitutional material used for rigid pavement construction has emanated through the millennia thereby amplifying the concern associated with its adverse effect on the environment. In this context, geopolymer concrete not only proposes a sustainable solution but also addresses the problems associated with extensive industrial waste generation and its imprudent disposal. This study aims to highlight the relevance of fly ash (FA) and red mud (RM) as geopolymer synthesizing source materials for pavement quality concrete (PQC). Investigations were designed to study the effect of varying replacement levels of FA (10%, 20%, 30%, and 40%) with RM in conjunction with different concentrations of sodium hydroxide in terms of molarity (10 M, 12 M, 14 M). The specimens subjected to ambient curing and oven curing at 60 °C were tested for compressive strength, flexural strength, and split tensile strength. Results portray that in the case of ambient cured FA-RM specimens, the highest compressive strength and flexural strength that could be achieved were 31.5 MPa and 4.32 MPa, respectively. Thereby, indicating inadequate strength development as per the requirements of PQC, even at a higher concentration of sodium hydroxide. Moreover, replacing FA with RM is mostly not effective at replacement values greater than 20% in both compression and tension. Furthermore, a defined study for assessing durability properties was also conducted by immersing the specimens in a 5% sulfuric acid solution. 11.46% and 7.25% reduction in compressive strength of control mixes was observed for specimens corresponding to 10 M and 14 M respectively, thereby substantiating decreased strength loss at higher molarity. [ABSTRACT FROM AUTHOR]

Fouling in convective parts of boilers is typical of the deposition of solid particles and condensable inorganic vapours. Particle sticking is caused mainly by gravity, adhesion, or the presence of a sticky liquid film of condensed vapours. Aside from the local conditions, particle properties and size determine whether they are sticking on the surface. This work focuses on simulations of particulate matter fouling of cooled tubes by fly ash produced by the combustion of industrial waste and sewage sludge mixture. Boundary conditions including the flue gas and particle flow rate are derived from combustion tests. Particle properties and size distribution are obtained from literature. The goal is to provide a basis for further modelling of the development of large deposits in tube bundles observed during a test on the experimental facility. Neither the combustion nor fly ash development is modelled. Their transport and deposition are simulated. Fixed boundary conditions are set for both the particulate and gas phases. The influence of already deposited particles on the surface mechanical properties and roughness is included to capture their deposition. The fly ash particles are considered completely solidified, considering the low flue gas temperatures on the facility inlet. [ABSTRACT FROM AUTHOR]

The present study directs the need for the development of an economical composite mix comprised locally available soil and industrial waste which satisfy the design parameters of the municipal solid waste (MSW) landfill. The local soil, bentonite, and fly ash mixtures are mixed in different proportions to evaluate the geotechnical and microstructural characteristics for suggesting an optimum composite mix that fulfills the design parameters of landfill liners. The curing periods of different mixes are also considered while evaluating the unconfined compressive strength (UCS) characteristics. The microstructure of the mixtures is examined using advanced imaging techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to gain insights into the changes at the microscale level due to the inclusion of fly ash. It is observed that soil-bentonite-fly ash composite mix in a ratio of 65:15:20 aligns with the optimal design characteristics required for a landfill liner. Notably, for this composite mix, both liquid limit (LL) and plastic limit (PL) show a significant increase of 48.57% and 32.33% respectively, while the optimum moisture content (OMC) rises by 11.25%. Conversely, maximum dry density (MDD) experiences an 8.79% decrease. Moreover, the free swell index (FSI) escalates by 113%, whereas hydraulic conductivity (HC) records a substantial reduction of 96.04%. Moreover, the UCS exhibited a notable increase of 209% after a 28-day curing period. The highest strength is achieved initially by soil mixed with 20% fly ash, followed by a blend containing 15% bentonite. Therefore, proper fly ash content in filler and other binder materials is an effective and sustainable approach that not only solves the disposal issue but also enhances the material's engineering characteristics, justifying its suitability to be used as a landfill liner. [ABSTRACT FROM AUTHOR]

In the context of ongoing rapid industrialization, the increasing deposition of industrial waste has arisen as a persistent global challenge, necessitating immediate attention and subsequent implementation of sustainable remedies. This study convenes on the efficacy of industrial wastes, namely fly ash and ground granulated blast furnace slag, as geopolymer concrete synthesizers in conjunction with the incorporation of reclaimed asphalt pavement (RAP) aggregates as a replacement for natural coarse aggregates varying over 25% to 100%. Under 7 days of ambient curing, employing 14M NaOH and a 50% RAP replacement, the mix achieved significant strengths of 41.80 MPa in compression and 4.72 MPa in flexure, affirming its suitability for pavement quality concrete (PQC). Through this study, the phenomenon of efflorescence could also be explored, which was particularly significant during the winter seasons. Furthermore, the declining coefficient of determination (R2) with the rise in RAP, observed in the correlation between compressive strength and ultrasonic pulse velocity (USPV), likely signified increased variability in the mixture at higher replacement levels. Assessment of long-term performance in terms of resistance to surface abrasion established the mix as durable, depicting minimal depth of wear (0.081 mm). Furthermore, results of the rapid chloride penetration test (RCPT) demonstrated that the presence of adhered asphalt in RAP aggregates reduces porosity and enhances resistance. Microstructural study was additionally conducted to comprehend the importance of adhered asphalt in impeding crack propagation. ANOVA established a highly significant relationship between the interaction of curing age and RAP fractions with the strength characteristics of the mix. [ABSTRACT FROM AUTHOR]

Warm mix asphalt mixtures became attractive paving mixes by reducing the production temperature to around 25–40 °C as compared to that of conventional hot mix asphalt (HMA). This study aims to evaluate the warm mix asphalt (WMA) using wax-based additives by incorporating two types of industrial wastes. The potential application of low calcium fly ash (FA), i.e. class F type and marble dust (MD), has been evaluated by varying different percentage. The cylindrical samples were prepared and assessed for moisture susceptibility by being subjected to Marshall stability, retained Marshall stability (RMS), indirect tensile strength (ITS) and tensile strength ratio (TSR) tests. Furthermore, the samples were also evaluated for finding the refusal density, Cantabro loss and the rutting performance. A scanning electron microscope (SEM) was also used to evaluate the size and microstructure of the filler particles. The results revealed that the inclusion of fillers into mixes had significant improvement in the mechanical properties and lowered the rutting value with FA and MD addition. The warm mix additive and fillers used were also useful in reducing the binder content of the mixes. The mixing temperature was found to be in the range of 120–130 °C using the warm mix additive. The optimum usage of FA and MD can be up to 5% based on the evaluation. The statistical results reported that there was a significant difference between FA-based and MD-based WMA. [ABSTRACT FROM AUTHOR]

Engineered geopolymer composites (EGC) have emerged as a more environmentally friendly alternative to conventional engineered cementitious composites (ECC). These composites offer high mechanical and durability features. However, there is a lack of research on EGC, particularly with basic oxygen furnace (BOF) slag as a precursor and iron ore tailings (IOT) as a partial replacement to fine aggregate. Despite their effectiveness as industrial waste products in conventional concrete, this study aimed to determine the optimal compositions of fly ash (FA), steel fibres (SF), and IOT by varying their percentages. Overall, 150 mix combinations were tested, including six binder combinations, five combinations of fine aggregates, and five percentage variations in SF. Finally, one optimum mix was selected for each binder combination, based on the ultimate compressive strength values corresponding to the six optimal mixes. The compressive strengths of all the mixes were evaluated at both 7 and 28 days of curing, involving three replicate samples after oven curing (initial 24 h) followed by subsequent ambient curing until their respective ages. The highest observed compressive strength after 28 days was 41.77 MPa for 50 mm cubes. This strength was achieved with a composition of 60% FA, 1.5% SF, and 45% IOT. An increase in IOT percentage led to a nearly linear increase in strength, while the strength peaked at 1.5% for steel fibres. The addition of BOF slag significantly enhanced the compressive strength compared to mixes with full FA. A 40% fly ash replacement with BOF slag resulted in an average strength that was 39% higher than the combination with 100% fly ash. However, the strength growth decreased after a 10% replacement. Analysis of variance was conducted using the design of experiments methodology to determine the significance of the parameters and their interactions. All three independent parameters were found to be statistically significant, while their interactions were not. Utilizing Taguchi's analysis method with the L25 orthogonal array, it was concluded that IOT percentage was the most influential parameter. [ABSTRACT FROM AUTHOR]

The mining operation is a challenging field for human development. Deep underground mining has increased as a result of the lack of economic minerals close to the surface of the ground. Mining companies are now thinking of backfilling mine wastes to prevent mine collapse during later and deeper extraction stages due to safety and environmental concerns. The production of waste products (for example, fly ash, slag, and tailings) during the processing of minerals, the production of electricity, and the production of metals is tremendous. There is a wealth of information available on employing fly ash, slag, and mine tailings as a partial substitute for cement, as well as for paste backfilling. Nevertheless, a thorough analysis of the use of industrial waste and mining tailings as mine backfill is mostly absent. This article offers a grave evaluation of the use of mine and industrial. Geotechnical characteristics, backfill material features, and issues relating to strength prediction are all examined. In addition to the aforementioned, the effects of substitute binders, such as industrial waste, are considered when modifying paste backfills utilizing admixture. The paper finished with future paths for mine paste backfilling study, specifically utilizing ordinary and non-natural essences for primary strength growth. Hence, continued use of such engineering waste supplies for mill paste backfilling might benefit from this research. [ABSTRACT FROM AUTHOR]

Conventional cement concrete has surfaced as a major construction material with considerable global warming potential. Alternatively, a fly ash (FA) ground-granulated blast furnace slag (GGBS)-based alkali-activated concrete is introduced to attain the goal of net zero emission and reduce the environmental impacts. In this study fixed proportions of concrete mixes matching with a designated strength of plain cement concrete mix have been determined. In addition to this, an ambient curing condition has been integrated that will be helpful for practical implementation in large-scale construction. Sodium silicate and sodium hydroxide were used as alkaline activator solutions to activate the FA and GGBS. The alkali activator reciprocity, i.e. Na2SiO3/NaOH (NS/NH), was set at 2.5. For various combinations of FA and GGBS, the main parameters considered in this study were molarity of sodium hydroxide and alkaline solution/binder ratio. The variation implemented in this experimentation includes: proportions of FA and GGBS (80–20, 75–25, 70–30, 65–35, 60–40, 55–45 and 50–50) and molarity of NaOH (10, 12, 14 M). Results concluded that the FA–GGBS-based alkali-activated concrete exhibits better performance as compared to conventional concrete. Furthermore, X-ray diffraction, Fourier transform infrared spectrography, scanning electron microscopy and energy-dispersive X-ray are carried out to investigate the behaviour of microstructure of GPC. Life-cycle impact category values have also been estimated considering all possible construction scenarios. [ABSTRACT FROM AUTHOR]

Recent advances in the field of composite materials, aligning them with cost-effectiveness and environmental sustainability, have made the development of materials from industrial waste an attractive area of research. This work introduces an innovative approach for the reuse of globally available industrial waste by hybridizing organic and inorganic by-products to create low-cost composite materials with synergistically enhanced performances. Herein, industrial wastes, namely powdered wood chips (PWC) from the woodworking industry and fly ash (FA) derived from bagasse burning, were incorporated in a thermoplastic polypropylene (PP). Hybrid PP/PWC/FA composites at 70/20/10, 70/15/15 and 70/10/20 wt% were manufactured via extrusion process, followed by injection molding. Micrographic observations and infrared spectroscopy reveal that PWC particles have good physical adherence with PP. In contrast, the hydrophilic nature of FA leads to the creation of gaps at the interface due to the poor interfacial adhesion. The latter difference is reflected in the combined void nucleation modes of particle–fracture and particles–matrix interface decohesion during hybrid composites' tensile deformation. This provides a good synergistic stiffening effect for 70/20/10 wt% PP/PWC/FA hybrid composite, which offers the highest Young's modulus improvement of about 44.43%, while benefiting from balanced tensile strength and strain at yield. Furthermore, a two-way ANOVA at a significance level of 5% also proved the significant effect of PWC and FA reinforcement on the tensile parameters, as the p-values were below 0.05. Melt rheological properties demonstrate complex viscosity decrement for hybrid composites, suggesting a reduction in the energy required during production. Overall, the novel, high-performance hybrid composites developed can be manufactured with less energy consumption and are suitable for applications requiring high-temperature resistance and stiffness such as automotive, construction, and beyond. [ABSTRACT FROM AUTHOR]

Stabilization and solidification (S/S) using cement and lime is a common remediation method for oil-polluted soils. Secondary stabilizers and industrial wastes have recently attracted research attention due to their lower cost and greater environmental compatibility as a full/partial replacement of cement/lime. This study examined the effects and mechanism of action of secondary stabilizers and industrial wastes on the geotechnical feature of oil-polluted soils with a review of the literature. The main objective was to provide a suitable platform to use these inexpensive and environmentally friendly materials for the treatment of oil-polluted soils. The other objective was to determine the magnitude of changes in geotechnical parameters of oil-contaminated soil using S/S. This research examined the effect of secondary stabilizers and industrial wastes, including fly ash, slag, rice husk ash (RHA), cement kiln dust (CKD), limestone powder, and nanoparticles in the S/S process; investigated the micro- and macro-structure of the S/S of oil-polluted soils after incorporating these materials; and discussed the advantages and major challenges of these substances. The dosage of the said materials for improving the geotechnical features of oil-contaminated soils in acceptable values was also determined. Based on the findings, 20–60% fly ash, 10–15% slag, 5% RHA, 5–10% CKD, and 2.25% nanoclay improve the geotechnical characteristics of oil-polluted soils. CKD used alone for the S/S of oil-polluted soil yields superior performance due to having similar performance and a chemical formula close to that of cement. CKD increases compressive strength by at least 70% more compared to other by-products. [ABSTRACT FROM AUTHOR]

The prolonged stacking of substantial volumes of industrial waste red mud (RM) can have significantly hazardous effects on the environment. In order to address this critical problem, this study proposes the synergistic preparation of geopolymers utilizing RM in conjunction with another industrial waste, rice husk ash (RHA). Geopolymers with varying incorporation of RHA were prepared using sodium hydroxide and sodium silicate composite alkaline activator. The mechanical properties, microstructure, and environmental characteristics of geopolymers were investigated. The incorporation of RHA significantly enhanced the strength of RM-based geopolymers, with the highest strength of 25.40 MPa achieved at 40% incorporation. According to XRD patterns and FTIR spectra, C-(A)-S–H and N-(A)-S–H were generated during the geopolymerization, thereby enhancing the strength of geopolymers. From SEM micrographs of geopolymers, it was evident that the geopolymer matrix was constituted by the encapsulation of unreacted inert particles of RM and residual fragments of RHA with C-(A)-S–H and N-(A)-S–H. The leaching levels of trace elements and heavy metals in geopolymers are both below the regulatory thresholds, thereby effectively mitigating the presence of hazardous substances in raw materials. These findings proved that the reuse of RM and RHA for the synergistic preparation of environmentally friendly geopolymers is a promising approach to address the issue of substantial RM stacking. [ABSTRACT FROM AUTHOR]

Fly ash is one of the largest types of industrial wastes produced during the combustion of coal for energy generation. Finding efficient and sustainable solutions for its reuse has been the subject of substantial research worldwide. Here, we review the recent research data related to (i) the use of fly ash as a low-cost adsorbent for pollutants in wastewater and soils and (ii) its implications in soil–plant system. Fly ash showed prominent adsorption capacity for pollutants in water especially when it was activated or applied in composites. In addition to direct pollutant binding in soils, fly ash can enhance the soil pH indirectly increasing metals' immobilization reducing their plant uptake. Its non-selective adsorptive nature may lead to the co-adsorption of nutrients with pollutants which merits to be considered. Owing to its considerable nutrient contents, fly ash can also improve soil fertility and plant growth. The effects of fly ash on soil physico-chemical properties, microbial population and plant growth are critically evaluated. Fly ash can also contain potentially toxic contaminants (toxic metals, hydrocarbons, etc.) which could have harmful impacts on soil health and plant growth. Identifying the levels of inherent pollutants in fly ash is crucial to evaluate its suitability as a soil amendment. Negative effects of fly ash can also be addressed by using co-amendments, biological agents, and most importantly by an adequate calibration (dose and type) of fly ash based on site-specific conditions. Research directions are identified to promote the research regarding its use in wastewater treatment and agriculture. [ABSTRACT FROM AUTHOR]

The stabilization/solidification (S/S) method is one of the most effective remediation techniques for treating contaminated soils. Several stabilizers, mostly the cementitious materials, have been used for the S/S treatment. In this paper, the feasibility of utilizing fuel fly ash (FFA) as a partial replacement of ordinary Portland cement (OPC) for the S/S treatment of marl soil contaminated with heavy metals was investigated. Two industrial waste materials, namely steel and electroplating wastes, were used to synthetically contaminate the marl soil. The stabilizers comprising of OPC and FFA were mixed with the contaminated soil at different dosages ranging from 10 to 40%, by mass, and a total of 48 S/S-treated soil mixtures were prepared. A series of experiments, including density, porosity, permeability, unconfined compressive strength (UCS), and toxicity characteristics leaching procedure (TCLP), were carried out on the soil mixtures to evaluate the efficiency of the proposed S/S treatment. Test results showed that the incorporation of FFA at higher volumes reduced the density and increased the porosity and permeability of the treated mixtures. Although FFA addition resulted in reducing the UCS values by an average of 46%, and this reduction was more significant at higher FFA percentages, the UCS values of all mixtures were more than 0.35 MPa (350 kPa), which passed the minimum requirements set by USEPA. In addition, the metal immobilization ability of the proposed treatment was confirmed by the TCLP analysis. As compared to the negative effect of the contamination of the soil by the electroplating waste, the contamination of the soil by steel waste had a higher negative effect. The results of this study would contribute in selecting an environment-friendly treatment of the contaminated soils using industrial waste materials, such as FFA, as a partial replacement of OPC. Nevertheless, the present study is an initial attempt to explore the possibility of utilizing FFA as a partial replacement of OPC in S/S treatment of marl soil contaminated with heavy metals. It is recommended to conduct another study in future including analysis of the treated soil mixtures using XRD, SEM, and FTIR techniques to better understand the stabilization/solidification mechanism and its implications on the test results. [ABSTRACT FROM AUTHOR]

Utilizing industrial wastes in concretes solves environmental issues such as disposal, depletion of natural resources, and CO2 emission. In this research, fly ash (FA) and ceramic tile waste (CTW) were used in making concrete. FA was used as a partial replacement for cement (30%), and CTW was used as a partial to total replacement for fine aggregate (10–100%). According to the experimental findings, 30% substitution of FA increased the compressive strength (10.05%), tensile strength (9.15%), flexural strength (6.9%), and elastic modulus (9.4%). The optimal level of CTW substitution in fly ash concrete was found to be 40%. At this level, compressive strength, tensile strength, flexural strength, and elastic modulus were increased by 10.56%, 9.3%, 6.9%, and 8.86%, respectively. The fly ash concrete mix with 40% CTW had higher electrical resistivity and reduced water absorption. The environmental sustainability of concrete mixes, as assessed by the CO2 emissions, was found to be lower by 21.5% in fly ash concrete as compared to reference concrete. With 100% CTW addition, the emission was lowered by 3.8%. The preparation cost for fly ash mix with 40% CTW was 14% less than the reference concrete. As an outcome of this research, the fly ash concrete with 40% CTW can be used with the benefits of improved strength, durability, sustainability, and cost savings. Box–Behnken design (BBD) models were developed to estimate the mechanical properties of the CTW-incorporated fly ash concrete, and excellent correlations were obtained between the predicted and experimental values. Effect of ceramic tile waste as fine aggregate in 30% fly ash additive concrete [ABSTRACT FROM AUTHOR]

Geopolymer is an environment friendly construction material that could be synthesized using either the natural source or the industrial byproducts such as flyash and GGBS. The characteristics of the Geopolymer rely on the proportion of the flyash and GGBS and the concentration of the activator solution used. In this research work, the effect of partial replacement of flyash with GGBS in proportions such as 0, 10, 20, 30 and 40% is investigated. Also Molarity of NaOH are tested from 8 to 14 M and both the parameters are optimized. In this optimized Geopolymer concrete, the utilization of iron slag as a partial substitute for river sand in various proportions such as 10, 15, 20, 25, 30 35, 40 and 45% are investigated. The optimized Geopolymer concrete with iron slag is investigated for its performance as a paver block with incorporation of banana fiber in proportions such as 0, 0.5, 1 and 1.5 and is compared with conventional cement concrete paver block. The results show that there is a significant enhancement in the properties of Geopolymer concrete with the different levels of optimization and the utilization of natural banana fiber. The developed sustainable paver block was found to with stand medium traffic conditions as per IS 15658:2006. Further this study employed random forest (RF) algorithm for the prediction of compressive strength of geopolymer concrete specimens for the variable parameters such as molarity of alkaline solution, Flyash/GGBS ratio and partial replacement of river sand with iron slag. The performance evaluation parameters represented high accuracy of developed RF model. This research work unleashes a heft potential of Geopolymer concrete to develop economical eco-friendly sustainable paver blocks to the society through mitigation of environmental strain on the ecosystem. [ABSTRACT FROM AUTHOR]

Advanced and eco-friendly construction materials are being developed to reduce pollution and improve wastewater treatment efficiency. One such material is a photocatalytic nanocomposite that uses industrial wastes and natural substances to eliminate pollution. A recent study explored using an inorganic polymer composite (FM) made from a mixture of 70% fly ash and 30% metakaolin, with sodium hydroxide and sodium silicate as an alkali activator. The study evaluated the mechanical and hydration characteristics of the FM composite after 28 days in 100% humidity at room temperature. The study also examined the effect of adding 2.5 wt.% of Nano-TiO2 to FM composite and how it affects its properties. Results indicate that adding Nano-TiO2 to FM composite enhances its mechanical, antibacterial, and photocatalytic capabilities. Specifically, FM-TiO2 composite showed 90% removal of reactive blue 19 dye effluent in sunlight after 90 min, making it an excellent choice for sustainable wastewater treatment. This study presents a cost-effective, eco-friendly solution to wastewater treatment, with added antimicrobial properties from Nano-TiO2. [ABSTRACT FROM AUTHOR]

Industrial solid waste has a wide range of impacts, and it is directly or indirectly related to land, atmosphere, water, and other resources. Industrial solid waste has a large amount of production, complex and diverse components and contains a variety of harmful substances. However, as industrial by-products, it also has a lot of available value. Industrial solid waste has been continuously studied in water treatment due to its special composition and porous and loose structure. It is known that there are few reviews of various industrial solid wastes in the field of wastewater treatment, and most of them only discuss single industrial solid waste. This paper aims to sort out the different studies on various solid wastes such as fly ash, red mud, wastewater sludge, blast furnace slag and steel slag in dyeing, heavy metal, and phosphorus-containing wastewater. Based on the modification of industrial solid waste and the preparation of composite materials, adsorbents, coagulants, catalysts, filtration membranes, geological polymers, and other materials with high adsorption properties for pollutants in wastewater were formed; the prospect and development of these materials in the field of wastewater were discussed, which provides some ideas for the mutual balance of environment and society. Meanwhile, some limitations of solid waste applications for wastewater treatment have been put forward, such as a lack of further researches about environment-friendly modification methods, application costs, the heavy metal leaching, and toxicity assessment of industrial solid waste. [ABSTRACT FROM AUTHOR]

Industrial waste as novel conductive mediator was applied for wastewater treatment as a novel strategy for both waste recycling and sustainable development of wastewater treatment. In this study, nanoscale zero valent iron-loaded fly ash-based activated carbon (nZVI@FABAC) was prepared and applied to enhancing activated sludge (AS) process for coal chemical wastewater (CCW) treatment. The results demonstrated that the removal efficiencies of COD and total phenols (TPh) in nZVI@FABAC/AS process reached about 83.96 and 85.17%, which increased 52.51 and 31.52% compared with the single AS process, respectively. And the acute toxic unit value of CCW was reduced by 88.24% after nZVI@FABAC/AS process treatment. The various functional bacteria including phenol-degrading bacteria (Comamonas and Acinetobacter), electroactive bacteria (Geobacter), and iron reduction bacteria (Geothrix) were enriched in the nZVI@FABAC/AS process, which provided various electron transfer pathways to improve the degradation of toxic organics in CCW. Accordingly, nZVI@FABAC/AS process provided a promising and sustainable way for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

The main objective of the present work is to evaluate using alkaline wastewater from pot factories (recycled NaOH solutions with variant concentrations and pH values) along with waste powders possessing pozzolanic properties, such as supplementary cementitious materials and stone waste dust in concrete under normal manufacturing conditions. An extensive analysis of the chemical components and the physical properties of the used materials was achieved. Both supplementary cementitious materials and stone waste dust materials were used as 0%, 10%, 20%, or 30% partial cement replacements using either tap water or alkaline wastewater to make samples for physical, mechanical, and microstructure testing. Thermodynamic modeling was used to evaluate the effect of the flushed alkaline industrial water and the powders on the hydration products. The results showed an increase in the workability of the mixes made with alkaline wastewater, an increase in water absorption for samples made with alkaline wastewater at the age of 28 days, and a relative decrease in compressive strength at 3 and 28 days, respectively. Despite the reduction in mechanical strength, most samples made with alkaline wastewater and 10%, 20% supplementary cementitious materials, or stone waste dust materials gave an accepted concrete grade. The microstructure analysis showed a slight change in pores distribution, pores values, and hydration products at 3 and 28 days. The thermodynamic analysis provided insight into data on the effect of supplementary cementitious materials, stone waste dust materials, and alkaline wastewater on hydration products. Finally, the combination of these wastes in concrete production showed satisfactory conclusions. [ABSTRACT FROM AUTHOR]

The main aim of this study was to develop and monitor an effective and cost-efficient industrial wastewater treatment system that utilizes sand, fly ash, and hearth ash. The latter two are potentially available and inexpensive industrial waste materials that can be used for filtration. The infiltration percolation method was utilized in a vertical cylindrical column to filter the raw wastewater from a detergent manufacturing plant. The main parameters analyzed before and after treatment included suspended solids (SS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and pH. The system successfully achieved significant reductions, including 89% in COD, 73% in BOD5, and 54% in suspended solids (SS), along with a 66% to 99% reduction in heavy metals. The COD/BOD5 rejection ratio decreased from above 4.24 before treatment to below 1.73 after treatment. Furthermore, impedance measurements were carried out across the frequency range of 100 to 1 MHz. The analysis of complex conductivity spectra revealed two Cole–Cole relaxation behaviors, and an equivalent circuit was developed to extract the primary parameters and further investigate both relaxation processes. The results of the electrical parameters deduced from the impedance spectra demonstrated a strong correlation with the parameters obtained through conventional methods. [ABSTRACT FROM AUTHOR]

Disposal of dyes wastewater into aquatic streams is considered as a major challenge due to its effect on water ecosystem. Direct dyes have a complex aromatic structure. Therefore, it is difficult to separate them from industrial wastewater. Conversely, fly ash is a main by-product pollutant generated from coal burning to fulfill energy requirements. In this study, thermochemical treatment process was applied to coal fly ash (CFA) in order to increase its surface area, improve its pore's structure and enhancing its adsorption capacity for direct blue 78 dye (DB78) removal. The treated coal fly ash (TCFA) was characterized by physicochemical analyses such as XRD, XRF, TGA, SEM, FTIR, surface area (SBET) and particles size analysis. Batch experiments were conducted to analyze the adsorption behavior for TCFA and to examine the DB78 dye removal efficiency. The physicochemical analysis results indicated that a higher increase in CFA surface area from 9.6 to 60.4 m2g−1 was obtained due to the modification process. The maximum removal efficiency using TCFA was 99.7% for initial dye concentration 10 mg/L and TCFA dose 2 g/L. The adsorption isotherm was studied by Langmuir and Freundlich model using different dye concentrations. The results showed that equilibrium data followed closely Langmuir isotherm model (R2 = 0.99) indicating monolayer and homogeneous adsorption process. [ABSTRACT FROM AUTHOR]

The use of industrial and biological waste to synthesize adsorbent materials for the treatment of high fluorinated geothermal water is a cost-effective way to address the fluorine pollution problem while also reusing waste resources. In this study, modified hydroxyapatite-loaded zeolite molecular sieve composites (Al(OH)3-HAP@ZMS) were synthesized using fly ash and shell as precursors, which were then cation doped and compound modified to ensure adsorption while remaining cost-effective. When the material ratio of ZMS to Al(OH)3-HAP was 1:6, the best adsorption material was obtained. Under the optimum adsorption conditions (dosage = 6 g/L, T = 50 °C), Al(OH)3-HAP@ZMS achieved a removal rate of 92.5% and an adsorption capacity of 1.56 mg/g for 10 mg/L F− solution and can reduce the F− concentration to below the national standard concentration of 1 mg/L. The fitting of kinetic, isothermal, and thermodynamic data revealed that F− adsorption by Al(OH)3-HAP@ZMS followed the pseudo-second-order kinetics and Freundlich model, confirming that the adsorption process was primarily chemisorption and multilayer adsorption. The adsorption processes included electrostatic attraction, ion exchange between -OH and F−, complexation of fluoro-aluminum, and co-precipitation of Ca2+ with F−. At the same time, Al(OH)3-HAP@ZMS demonstrated good anti-interference performance in natural waters against co-existing ions and some heat resistance. Therefore, the composite adsorbent Al(OH)3-HAP@ZMS, as an effective and environmentally friendly low-cost adsorbent, is expected to achieve the practical engineering application of geothermal water defluoridation in Guanzhong, maximizing the dual benefits of "fluoride remove" and "waste resource reuse." [ABSTRACT FROM AUTHOR]

The storage and disposal of fly ash, which is generated as an industrial waste of thermal power plants, is a challenging process, as is the case with all wastes. In this study, it is aimed to obtain a useful product for methylene blue adsorption by using fly ash in the production of foamed geopolymer. Geopolymers, which were obtained by doping Zn and Al metals, were cured in 2 different environments, at room conditions and at room conditions with pre-curing at 80 °C. NaOH and Na2SiO3 solutions were used for geopolymerization. X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), Brunauer, Emmet, and Teller surface area analysis (BET), and X-ray diffraction (XRD) analysis were applied for the characterization of fly ash and geopolymers. It was observed that optimum geopolymer sample produced has 27.355 m2/g surface area. Langmuir isotherm (R2 = 0.9962) was the most suitable adsorption isotherm in adsorption studies with the optimum geopolymer sample. The highest adsorption efficiency was obtained 97.4% in 50 ppm solution. As a result, it was observed that the geopolymer surface area could be increased by using chemical foaming method and obtained geopolymer could be successfully used for methylene blue adsorption. [ABSTRACT FROM AUTHOR]

A new type of inorganic fiber-fly ash continuous fiber was innovatively developed in this study to alleviate the problems of low comprehensive utilization rate and lacking of high-value utilization means of industrial solid waste fly ash. The melt flow temperature and macro-mechanical properties of different samples were studied. The results showed that with the increase in acidity coefficient index (MK), the melt flow temperature decreased first and then increased, and the lowest value was 1340 °C when MK was 3.1. Meanwhile, with the gradual increase in MK, the tensile strength and elastic modulus of monofilament increased first and then decreased. When the MK was 3.8, the tensile strength and elastic modulus of fiber monofilament reached 2064 MPa and 16.7 GPa, respectively. According to the results of XRD, TG-DSC, FTIR and SEM microstructure analysis methods, it is found that the macro-mechanical properties of fibers are closely related to the chemical composition and phase structure evolution of raw materials. After melting at high temperature, the samples with high MK form a dense three-dimensional glassy network structure, which leads to the higher mechanical strength of the fibers. However, in the samples with lower MK, the vitreous network structure is loose, which reduces the mechanical properties of the fiber. Finally, the MK range (2.5–3.8) for preparing high-performance fly ash fiber was proposed in this paper. In this range, the synthesized fly ash continuous fiber has low melting temperature and excellent mechanical properties, which has a potential of industrial application. [ABSTRACT FROM AUTHOR]

The concentrations and profiles of 18 polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM10), fly ash (FA), and bottom ash (BA) were examined in three incineration residues. Samples were collected from different municipal and industrial solid waste incinerators in Northern Vietnam. The average concentrations of total PAHs in PM10, fly ash, and bottom ash were 9.55 × 103 ng/Nm3, 215 × 103 ng/g, and 2.38 ng/g, respectively. Low-molecular-weight PAHs (2 to 3 rings) were predominant in most samples. The emission factor of total PAHs decreased in the order of FA > BA > PM10. A higher concentration of total PAHs was found in industrial facilities than that in municipal ones. The high carcinogenic proportion of PAHs together with significantly high annual emissions reflect the high pollution risk to the ecosystem by PAHs in the case of reuse of incineration ashes (e.g., brick production). Regarding the carcinogenic risk of PAH-bounded ashes or particles, calculations from this study imply the significant threat for workers who have been manipulated in the incineration facilities, directly exposed to fly and bottom ashes. Meanwhile, the risk from PAH-bound particulate was not considered a significant threat for both normal adults and children. Further study on PAHs contained in incinerator waste dumps should be conducted in Vietnam to assess the potential contamination risk of these incineration by-products. [ABSTRACT FROM AUTHOR]

The synthesis of silica nanoparticles (SiNPs) has emerged as an extensive area of research in the last century. Owing to their instinctive properties like modifiable mesoporous structure, high surface area, adjustable pore size, and pore volume, SiNPs could be utilized in numerous fields like chemical, biochemical, catalysis, adsorption, and pollution control. Conventionally, SiNPs are produced by tetraethylorthosilicate (TEOS), tetramethylorthosilicate (TMOS), and sodium silicate, which are toxic and expensive. Therefore, the development of green, cost-effective approaches for the synthesis of SiNPs is highly desirable. In this course, during the last decade, silica-rich solid wastes (rice husk, corn cob, sugarcane bagasse, palm ash, fly ash, waste glass, waste packaging materials, photonic industrial wastes, etc.) were acknowledged as economical precursors to produce green SiNPs. In this respect, the present review focuses on reviewing several solid waste materials used for the synthesis of SiNPs, their properties, and different characterization techniques used for the analysis of SiNPs. The present review also accounts for the potential applications of such green SiNPs in several fields like catalysis, adsorption, biomedical applications, and energy storage. Moreover, despite the potential applications of SiNPs, still there is a lot to explore about their synthesis and utilization. Hence, in the last section of this review, future scope, challenges, and risk assessment of SiNPs have been discussed. [ABSTRACT FROM AUTHOR]

Aerated concrete (AAC) or lightweight concrete is primarily used for non-load bearing structures in construction work. Generally, it is produced with cement as a main binding ingredient, and the production of cement is blamed to contribute 7 to 8% of CO2 emission in the environment. In addition, the dumping of industrial wastes is also a great environmental concern. This research is an attempt to produce low-cost and sustainable aerated concrete utilizing silica fume and fly ash as partial substitution to cement without compromising the fundamental properties of aerated concrete. The current study was divided into two phases: in the first phase, the silica fume was substituted up to 20% with a variation of 5% in each mix. In the second phase, the fly ash was replaced with cement in three variations, i.e., 10%, 20%, and 30% containing an optimum proportion of silica fume obtained in phase 1. The aluminum powder was added at 0.4% by weight of binder to introduce aeration in concrete. Before testing, samples of aerated concrete were cured with steam in an autoclaving machine for 9 h at a pressure and temperature of 1.5 bars and 127 °C respectively and oven-dried at a temperature of 105 °C for 24 h after steam curing. From the experimental results, the highest compressive and split tensile strength of AAC was recorded when 15% of the cement was replaced with silica fume and 30% of the cement was replaced with fly ash combined. At this proportion the least density was also recorded which showed the lightweight of AAC without compromising the strength characteristics. In addition, the reduction of 42.64% and 32.4% of embodied carbon and cost was observed respectively. [ABSTRACT FROM AUTHOR]

The discharging of lead-contaminated wastewater is a concern because of its toxicity to living organisms and water quality resulting in dangerous water consumption, so it is highly recommended to remove lead from wastewater to be below water quality standards for a safe environment. Zeolite A sugarcane bagasse fly ash powder (ZB), zeolite A sugarcane bagasse fly ash powder mixed iron(III) oxide-hydroxide (ZBF), zeolite A sugarcane bagasse fly ash beads (ZBB), zeolite A sugarcane bagasse fly ash powder mixed iron(III) oxide-hydroxide beads (ZBFB), and zeolite A sugarcane bagasse fly ash beads coated iron(III) oxide-hydroxide (ZBBF) were synthesized and characterized in various techniques. Their lead removal efficiencies were investigated by batch experiments, adsorption isotherms, and kinetics. The specific surface area, pore volume, and pore size of ZB were close values to zeolite A standard (STD), and ZBF had the highest specific surface area and the smallest pore size than others. ZB and ZBF demonstrated crystalline phases whereas ZBB, ZBFB, and ZBBF were amorphous phases. The surface morphology of ZB was a cubic shape similar to STD. ZBF demonstrated an agglomerated formation of ZB and iron(III) oxide-hydroxide whereas ZBFB and ZBBF had sphere shapes with coarse surfaces. Si, Al, O, Fe, Na, Ca, O–H, (Si, Al)–O, H2O, and D4R were detected in all materials. The surface charges of all zeolite A materials had negatively charged at all pH values, and their surfaces increased more negatively charged with increasing pH value which pH 5 illustrated as the highest negatively charged in all materials. Their lead removal efficiencies were higher than 82%. Langmuir isotherm and pseudo-second-order kinetic models were well explained for their adsorption patterns and mechanisms. Finally, ZBBF is a good offer for applying in industrial wastewater treatment systems because of its easy operation and saving costs than ZBF. [ABSTRACT FROM AUTHOR]

Water pollution has become one of the most acute environmental problems. One of the pollutants coming to water bodies from industries are dyes, which are harmful to human health, living organisms, and the esthetic appearance of water. Most dyes are toxic, carcinogenic, rarely biodegradable, and highly soluble in water. Therefore, industrial wastewater treatment has become important. Adsorption technique of removal of dyes from water is simple, efficient, and inexpensive as compared to other techniques. Adsorption efficiency depends on the type and surface area of adsorbents. Iron-rich coal fly ash (IRCFA)–Polydopamine (PDA)@ Silver (Ag) nanocomposite was prepared by separating the iron-rich part (IRCFA) from coal fly ash and coated with polydopamine. IRCFA was mixed with 10 mM tris buffer solution containing 1 g dopamine. The prepared IRCFA-PDA was added to an aqueous solution of silver nitrate, heated at 60 °C, and then 30 mL of flower waste extract was added to this solution. Solid IRCFA-PDA@Ag was obtained, and the prepared nanocomposite was used for the removal of methylene blue (MB) dye from water. The nanocomposite used was prepared by a cost-effective method and has high reusability, separability, and fast regeneration ability. The mechanism of removal of MB dye has been discussed in detail. [ABSTRACT FROM AUTHOR]

Gold mine tailings, fly ash, and bagasse ash has been repurposed to produce geopolymer (GP) with enhanced electromagnetic interference shielding efficiency (EMI-SE) and high thermal property. GP has low shielding efficiency compared to concrete. Due to this, an appropriate filler must be incorporated into its matrix to enhance its EMI-SE. For this study, bismuth oxide nanomaterial (BiNP) was utilized as the additive filler. The percent content of BiNP was varied to evaluate its influence on the EMI-SE of GP. Morphology shows that Bi2O3 was embedded in the matrix of GP, and no new aluminu-phyllosilicate minerals were formed. This indicates that some minerals acted only as internal fillers in the matrix. Compressive strength shows synthesized GP composites were more than 20 MPa, with neat GP reaching the maximum strength. Moreover, the EMI-SE of neat GP was 21.2 dB for 20–4500 MHz range. This indicates that GP alone has sufficient characteristics to attenuate EMI radiation. Addition of 5%, 10% and 15% weight of BiNP improves EMI-SE by 4–10%, with 5% BiNP shown to be the optimum ratio. Lastly, the addition of BiNP improves the thermal stability of GP. This study shows that GP incorporated with Bi2O3 can be recommended for small-scale construction and small residential building. [ABSTRACT FROM AUTHOR]

To reduce the filling cost of high-water backfilling material (HWBM) in mining backfill and improve the recycling utilization of the industrial waste such as the coal fly ash. The ultra-fine fly ash (UFA) was added to the HWBM as a partial replacement in this work. Therefore, a series of experiments were performed to investigate the effect of UFA on the mechanical properties of the HWBM at the different curing conditions, then the hydration mechanism of the HWBM blended with UFA was analyzed by XRD and SEM method. The result indicates that the strength of the HWBM decreased with the increasing of UFA dosages, but the addition of UFA can improve the residual strength of the initial HWBM. Additionally, when the HWBM was cured at the laboratory air condition, its carbonation process was restrained obviously as the UFA dosages were less than 15% at the ages of 28 days, which indicates the UFA can improve the weathering resistance of the HWBM with the curing ages increasing effectively. The XRD and SEM results also shows that the degree of crystallinity of the HWBM increased when UFA dosages were less than 15% effectively, while there were few obvious changes on types of hydration products. It indicates that the main affects of UFA on the performance of HWBM is filler and dilution, which reduced the contact area between hydration products of HWBM and CO2 in the air, further improved the carbonation resistance of HWBM. [ABSTRACT FROM AUTHOR]

A new adsorbent with chromium removal function was synthesized by carbon thermal method using iron-containing waste Fenton sludge and carbon-containing solid waste fly ash to treat high pH scoring wastewater generated from industrial processes. The results showed that the adsorbent used T = 273.15 K, pH = 10, t = 1200 min, C0 = 100 mg/L, had a removal rate of Cr(VI) of more than 80%, and the adsorption capacity could reach 393.79 mg/g. The characterization results show that the synthesized mesoporous nitrogen-doped composite material has a large specific surface area and mesoporous structure, and the surface of the material is rich in oxygen-containing functional groups and active sites. Compared with other studies, the adsorption capacity of the material is larger, which indicates that the removal effect of Cr(VI) in this study is better. The adsorption kinetic results show that the adsorption follows a pseudo second kinetic model, and the adsorption process is a chemisorption involving electron sharing or electron exchange. This experiment designed a simple method to synthesize mesoporous nitrogen-doped composites using industrial solid waste, with raw materials from cheap and easily available industrial solid waste, and solved the dual problems of heavy metals in wastewater and solid waste, providing a new idea for the resource utilization of Fenton sludge while not producing secondary pollution. [ABSTRACT FROM AUTHOR]

The infrastructure development of a country is focussed on the development of roadways that includes the construction of many bridges and flyovers with retaining walls. The construction of the mechanically stabilized earth (MSE) retaining wall gained momentum since 1960 owing to the various beneficial aspects in terms of its durability, economy, stability, appearance, sustainability aspects, etc. A typical MSE retaining wall is a composite structure made up of compacted backfill and reinforcement elements, fixed to a wall facing. The increasing rate of urbanization leads to the development of more industries resulting in the production of wastes such as fly ash, waste foundry sand, pond ash, slags, etc. The disposal of these wastes is often a big issue for the industries, and hence, their utilization in the construction industry is studied by researchers to solve the problem of waste dumping. This review article summarizes the studies involving the potential use of industrial waste material as reinforced earth fills in the MSE retaining wall. The researchers used waste materials from industries like thermal power plant, mining, construction, metal smelting units etc. The important fill properties such as particle size, friction angle, and density were compared with the standard codal provisions. The different dimensions of the research experiments involving the MSE backfill using various industrial wastes were presented in this review. [ABSTRACT FROM AUTHOR]

The cost, flux and rejection rate of the membrane are the main factors in the process of water reclamation and reuse. A new type of composite membrane can be prepared by using fly ash (FA) and polyurethane (PU). The structure and properties of composite membrane can be adjusted by the theory of pigment volume concentration (PVC) to treat wastewater containing methylene blue (MB). The morphology, FT-IR spectroscopy, wettability, diffusivity, flux and rejection rate of the composite membrane were studied. The results showed that when PVC was close to the critical pigment volume concentration (CPVC), the performances of the 3# (PVC = 40.03%) composite membrane, the mass ratio of FA to PU was 1.44: 1, were the best. The flux and rejection rate for MB solution of the 3# membrane were 66.52 L·m−2·h−1 and 96.77%, respectively. At the same time, there was no serious pollution on the membrane with a long-term application. In addition, several typical organic wastewaters were treated by this composite membrane. The rejection rates for organic pollutants such as Rhodamine B, phenol and actual industrial wastewater were 96.12%, 96.48%, and 97.58%, respectively. The sustainable technology for the recovery and reuse of water by using solid waste in wastewater treatment has good environmental and social benefits. [ABSTRACT FROM AUTHOR]

The primary goal of this research is to determine the mechanical properties of opaque glazed ceramic tiles containing fly ash, tincal waste, and recycled red clay, including to assess if the results meet international requirements. Opaque glaze and tincal waste were the main components of all glaze compositions of four groups, which were named OG (original), FA, RC, and FC (mixture) according to the additive. The ceramic tiles were prepared by dipping the biscuits in the glaze composition and firing them at 1150°C. The water absorption of the FA, RC, and FC tiles was less than that of the OG tiles (< 0.52%) and the scratch hardness values were between 6 and 7. All the experimental groups were also resistant to thermal shock, chemicals, and staining showing high opacity (L* > 92) and having a light yellow–red color. The micro- and crystallographic structure of some selected tiles were determined by scanning electron microscopy and x-ray diffraction techniques. Zircon, diopside and augite phases were recognized. [ABSTRACT FROM AUTHOR]

Dewatering applications are carried out with geotextile tubes for the disposal or reuse of industrial wastes with high water content. Class F Seyitomer thermal power plant fly ash, an industrial waste, was selected in this study. Turbidity, sedimentation and filtration experiments were carried out using anionic and cationic polymers and polypropylene synthetic fiber to investigate the effect of polymers and fibers on the dewatering of fly ash. The use of polymers was determined to significantly accelerate filtration and soil sedimentation speed while leading to a slight increase in the volume of the filter cake. When effective polymer and dosage are used, slurry filtration time can be reduced up to one-eighth of the time and dewatering can be achieved much faster. The addition of synthetic fiber accelerated the sedimentation of the slurry and increased the filtration in the vertical direction, while it did not show a significant effect on the total filtration in two-dimensional filtration. In geotextile tube applications, although one-dimensional filtration experiments might give misleading results in terms of estimating the effectiveness of the polymers used in solid–liquid separation and dewatering times, the jar test, sedimentation and two-dimensional filtration experiments were determined to give compatible and more realistic results. In two-dimensional filtration experiments, approximately 75% of the filtration occurred in the radial direction and the dewatering time was approximately 21–55% of the time estimated by one-dimensional filtration experiment. Geotextile tube dewatering design can be made more predictable and cost-effective in the field by performing small-scale laboratory experiments with the two-dimensional filtration test system designed for this study and various dewatering applications. [ABSTRACT FROM AUTHOR]

One-part alkali-activated materials (AAMs) are developed to improve conventional two-part systems. One-part AAMs technology has been used in cement binders to produce concrete, mortar, and paste. Current research mainly focuses on synthesizing raw materials obtained from industrial and agricultural waste as the main aluminosilicate precursors of the cement binder for a concrete application. The one-part AAMs were reported to have higher early compressive strength at 7 days of age, contributed by its fast-setting time, mainly when the binder activates by a higher dosage of alkaline activator and containing OPC-rich. Due to bonding issues, single or combination, FA/GGBFS/MK precursors were reported as unsuitable for use as a concrete repair material. They were the reason for the lack of one-part AAMs application of mortar compared to concrete usage. This study was conducted to determine the potential of one-part AAMs used as concrete patch mortar by investigating its rheology and mechanical properties. The compressive strength of the mortar was tested under lab ambient temperature in the tropical climate country of Malaysia. The setting time of fresh mortar and bonding strength were set under controlled lab temperature. The one-part alkali-activated mortar was composed of hybrid aluminosilicate precursors between fly ash (FA), Ground Granulated Blast Furnace Slag (GGBFS) and ordinary Portland cement (OPC). A low alkaline activator of solid potassium carbonate was used for the geopolymerization process. Three types of solid admixtures were added to complete the composition of the new mix design. The experiment's outcome showed that the mortar composed with the combination of conventional Portland cement and industrial waste products has compressive and pull-off adherence strength that meets with Class R3—EN1504-3 standard for structural concrete repair materials requirement. [ABSTRACT FROM AUTHOR]

This study investigates the potential of a blended binder formulated from two industrial solid wastes viz. phosphogypsum and fly ash in combination with lime. Three mix proportions of phosphogypsum and fly ash were investigated, and the minimum lime contents required for activation were determined using the Eades and Grim pH test. The lime–fly ash–phosphogypsum blends were then cast into cubes, both in their paste form as well as mortar form, mixed with sand in the ratio of 1:3. They were cured for a period of seven days, and afterwards, their compressive strength was determined. Ordinary Portland cement and lime mortar blocks were also cast as control specimens for comparative evaluation of the strength. The optimal lime–fly ash–phosphogypsum blend was identified and used to construct a masonry prism, and the strengths of the masonry prisms were also evaluated. The optimal lime–fly ash–phosphogypsum blend mortar was also subjected to an X-ray diffraction analysis to determine the reaction products formed during hydration. The study revealed that 5% lime mixed with fly ash:phosphogypsum in the ratio of 3:1 was the optimal proportion which gave the maximum strength to the cubes. The optimal lime–fly ash–phosphogypsum blend mortar developed strength that was higher than conventional Portland cement and lime mortar. The optimal lime–fly ash–phosphogypsum blend mortar masonry prisms developed strength that was comparable to that of Portland cement mortar masonry. The X-ray diffraction analysis revealed the formation of calcium silicate hydrate minerals as well as ettringite and portlandite which were responsible for strength gain. [ABSTRACT FROM AUTHOR]

Recycling industrial wastes is necessary for the economy and the environment. Additionally, it is important to develop high-efficiency adsorbents to prevent severe water pollution caused by wastewater containing dye agents. Here, poly(2-acrylamido-2-methylpropane sulfonic acid)-fly ash composite hydrogel was synthesized with a variety of fly ash proportions with the radical polymerization method. The synthesized composite hydrogel was used for adsorption of methylene blue and methyl orange dyes from water containing dye agents. A variety of parameters such as initial dye concentration, solution pH, anion effects, temperature, contact time and adsorbent amount were investigated for optimization of the adsorption process. The poly(2-acrylamido-2-methylpropane sulfonic acid)-fly ash composite hydrogel was determined to be an effective adsorbent to remove both the cationic dye methylene blue (1438.68 mg g−1) and the anionic dye methyl orange (646.54 mg g−1). Experimental adsorption data were assessed with a variety of isotherm and kinetic models. It was determined that the adsorption of both dye molecules abided by the pseudo-second-order kinetic model. The thermodynamic parameters were determined as ΔH° = − 15.77 ± 5.22 kJ mol−1, ΔS = − 45.05 ± 16.42 J mol−1 K−1 and ΔG° < 0 for MB, ΔH° = − 20.13 ± 4.83 kJ mol−1, ΔS = − 72.87 ± 15.20 J mol−1 K−1 and ΔG° > 0 for MO. In conclusion, a material was synthesized that can be used as a single adsorbent composite material for both anionic and cationic dyes. In addition to the perfect adsorption capacity of this material, it offers reusability and a broad area of application for a variety of dye agents. [ABSTRACT FROM AUTHOR]

The study proposes a novel and sustainable method to appropriately utilize wastes from granite as well as glass industries in brick manufacturing. An ecofriendly and low-cost manufacturing process of ash-based bricks pertaining to the Indian standard codal provisions that can be adopted on the commercial scale is deliberated. The research also recommends the method for predicting the strength of the ash-based bricks using machine learning algorithms like random forests and decision trees. For positive synergy in the performance, both the granite tailings and glass waste must be used together. Using the granite tailings and glass waste together led to a significant reduction of 75% in the fly ash requirement without compromising the brick's performance. The addition of the granite tailings and glass waste in the mix could increase the strength of the brick by 90.5% and 37.7%, respectively. Beyond 30% dosage of granite, tailings are not recommended as they may lead to the poor gradation of particles and weak bonding in the microstructure. The glass waste in the mixture should not be more than 15% as it causes the dilution of pozzolanic reactions thereby forming fewer hydrated compounds. Brick's durability is known after exposing the specimens for 1 year to sewers and biogenic corrosion environment, marine environment, and saline soil environment, respectively. The inclusion of the industrial wastes significantly reduced the specimen damage in the extreme environmental conditions along with the least absorption rates. The dosage of ash, granite tailings, and glass waste has to be maintained around 15%, 30%, and 15%, respectively for attaining the optimum performance. Out of the generated machine learning algorithms, only random forests could be able to predict the values accurately with R2 values at 0.90 and with comparatively lesser errors. [ABSTRACT FROM AUTHOR]

A specific mortar material (abbreviated as RFT) was designed from industrial solid wastes, such as red mud, fly ash, and iron tailings. It was mainly developed for 3D printing in this work. Mechanical properties, microstructure and heavy metal leaching properties were discussed. The RFT composed of 15% red mud, 45% iron tailings, 9% fly ash, 30% cement, and 1% FDN water reducing agent attained good mechanical properties. Hydration products including Ca(OH)2, ettringite and C-S-H gel were found in RFT through SEM observation. Iron tailings mainly acted as fine aggregates in RFT, and they were wrapped by the C-S-H gels, producing a strong bonding effect between aggregates and cementitious matrix. The leaching toxicity test results proved that the developed RFT mortar materials were environmentally acceptable. Finally, RFT was subjected to a 3D printing test to verify its feasibility as 3D printable construction material. [ABSTRACT FROM AUTHOR]

Present invention was indented for characterization and adsorptive (batch and column) treatment of sugar industry distillery spent wash to remove COD (chemical oxygen demand) and color using sugarcane industrial waste, bagasse fly ash (BFA). Distillery spent wash was extremely polluted including acidic pH and very high value of COD, BOD (biological oxygen demand) and color. Sophisticated techniques such as BET (Brunauer–Emmett–Teller) surface area, pore volume, pore diameter, particle size distribution, porosity, FTIR (Fourier-transform infrared spectroscopy), chemical composition by XRF (X-ray fluorescence) and SEM (scanning electron microscopy) were utilized to analyze BFA as an adsorbent and revealed that BFA surface was highly porous and consisted of various oxides. In batch treatment, different process parameters such as contact duration and temperature w.r.t adsorbent dose, thermodynamic studies and isotherms (Langmuir and Freundlich model) were analyzed. Column adsorption was performed using various variables (bed height, particle size distribution and flow rate), breakthrough parameters and isotherms (Thomas, Yoon–Nelson, BDST and Adams and Bohart model). Adsorption capacities were increased with increasing BFA dose, contact duration, temperature, bed height and decreasing flow rate and average particle size. The maximum adsorption capacity of Langmuir and Thomas model was achieved up to 124.5 mg g−1 and 0.1394 mg g−1, respectively, for COD and 109.8 (Hazen L) gm−1 and 0.2547 (Hazen L) gm−1, respectively, for color. Sugar Industry wastewater stream, i.e., distillery spent wash was shown to be feasible using own industrial solid waste, BFA. [ABSTRACT FROM AUTHOR]

Manufacturing waste has been quickly increasing over time as a result of the fast-rising population as well as the consumption of foods that are thrown away dishonestly, resulting in environmental contamination. As a result, it has been suggested that industrial waste disposal may be considerably reduced if it could be integrated into cement concrete manufacturing. The aim of this study is to analyze the properties of concrete employing waste glass (WG) as a binding material in proportions of 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The fresh property was assessed using a slump cone test, while mechanical performance was assessed using flexural, compressive, splitting tensile, and pull-out strength after 7, 28, and 56 days. Furthermore, microstructure analysis was studied by scan electronic microscopic (SEM), Fourier-transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA) test. The results reveal that the addition of discarded glass reduces the workability of concrete. Furthermore, mechanical performance was increased up to a 20% substitution of waste glass and then gradually declined. Waste glass can be employed as a micro filler or pozzolanic material without affecting the mechanical performance of concrete, according to microstructure research. [ABSTRACT FROM AUTHOR]