Worldwide consumption of hen eggs is quite high, which results into availability of large amount of discarded egg wastes, particularly egg shell (ES) and egg shell membrane (ESM). Disposal of ES and ...ESM is always a problem particularly to the authorities of food, bakery and poultry units. In recent years, attempts have been made to utilize ES and ESM for the production of biodiesel and collagen but results are not much economically viable.
In the hunt of waste materials as potential scavenger of hazardous chemicals, ES and ESM have emerged as non-toxic, versatile and efficient adsorbents. Last 10years have witnessed a systematic growth in the use of ES and ESM as adsorbents for the removal of variety of organic as well as inorganic hazardous chemicals, particularly from wastewater. Literature survey reveals that ES and ESM in their natural as well as chemically modified forms have provided excellent results for the removal of various classes of dyes, oxalic acid, phenol, pesticides, humic acid, pharmaceutics, surfactants, PAHs, heavy-, precious- and light- metals, actinides, fluorides, etc. In recent years powdered ESM have been modified to nano-particles and used as adsorbent in various interesting applications. Reports are also available on the use of nanostructured material CHAP, derived from ES, for the removal of cadmium and lead ions from waste water.
Present review article is an attempt to summarize the research carried out on the above mentioned applications of ES and ESM. Overall 108 research articles have been included in this review, which describe a methodical growth in the subject matter.
•The review aims to describe use of egg shell and egg shell membrane as adsorbent.•Both ES and ESM can efficiently remove hazardous inorganic and organic pollutants.•Up-to-date information on the subject matter is presented in the review article.•Review contains future prospects and challenges associated with egg waste materials.
Radar systems, communication tools, and stealth technologies are just a few of the many areas that can benefit from microwave absorption materials (MAM). In an effort to promote sustainable and ...environmentally friendly solutions, researchers have turned their attention to waste materials as a potential resource for the development of efficient microwave (MW) absorbers. In order to lessen the effects of electromagnetic (EM) pollution, ferrites are frequently used as microwave-absorbing materials. However, the insufficient dielectric loss capacity is the fundamental constraint that limits their application. The MnFe2O4 was produced independently, while activated carbon (AC) was created using coconut shell. The MnFe2O4/AC composite was subsequently synthesized using a hydrothermal approach. From the research, the dielectric loss and magnetic loss of the S2 composite operate together. The incorporation of magnetic components contributes to the outstanding magnetic loss ability, while the nano-domain, hopping mechanism of the resonance effect is responsible for the improved dielectric qualities. S2 exhibits a minimum reflection loss of ‐38.4 dB at a thin thickness of 1.8 mm with an effective absorption bandwidth (EAB) of 6.2 GHz at the same thickness from 11.2 to 18 GHz. MnFe2O4/AC shows promise as a novel class of EM absorption materials because of their simple fabrication and high EM dissipation capacity.
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•Activated carbon (AC) was prepared from coconut shell waste.•AC-encased MnFe2O4 composites with porous microstructures were synthesized.•The encasing of MnFe2O4 in porous structure elevated intrinsic permittivity and dielectric losses.•The porosity in microstructure amplified interfacial polarization leading to attenuation mechanism and conductance losses.•Effective absorption bandwidth is 6.2 GHz at 1.8 mm and Rlmin is −38.41 dB.
Early risk identification of the sources and causes of waste material for road construction projects has been carried out, and the research continues to carry out further risk identification which ...then becomes the final risk identification. Description and validity tests and reliability tests were carried out to obtain further risk identification. Each source variable and indicator of the cause of material waste in each material is differentfrom one another because each has a difference. The results of continued identification resulted in: 1) ready mix concrete has eight variables of waste material sources and 21 indicators of material waste causes, 2) lean concrete has seven variables of waste material sources and 18 indicators of material waste causes, 3) aggregate B has seven variables of waste material sources and 12 indicators of material waste causes, 4) landfill has eight variables of material waste sources and 26 indicators of material waste causes, 5) cement has seven variables of material waste sources and 31 indicators of material waste.
Municipal solid waste incineration fly ash (MSWIFA), as a hazardous solid waste, contains such toxic substances as heavy metals and dioxin, making its disposal a global public health concern. This ...study aims to comprehensively combine solid waste red mud (RM), carbide slag (CS), and MSWIFA into eco-friendly geopolymer. This experiment used CS slurry and RM slurry without drying and grinding, effectively reducing energy consumption and cost. The mechanical and environmental properties of geopolymer were characterized by strength, chloride ion curing rate, and leaching concentration of heavy metals. The microscopic hydration mechanism of the binder was investigated using XRD, FTIR, TG-DTG, SEM + EDS, and MIP tests. The results show that when RM: CS: MSWIFA = 5: 2: 3, the 28 d compressive strength can reach 11.7 MPa, the chloride ion curing rate is 80.41%, and leaching levels of toxic substances are lower than the limits for landfill disposal regulated by the China standard (GB16889-2008). The Al–O and Si–O chemical bonds in RM were broken in the alkaline environment provided by CS and MSWIFA, and formed hydrate calcium chloroaluminate (HCC) and C–S–H gel with calcium ions and chloride ions. These hydration products can fill pores and reduce porosity, making the pores in the structure mainly gel micropores and mesopores with volume fractions of 10.3 and 68.1% respectively. This study expands the application of a new waste alkaline activator in alkaline activation and provides methods for MSWIFA solidification.
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•The synergistic use of CS and MSWIFA as alkaline activators outperformed single mixing.•The highest compressive strength was obtained with a RM-to–CS–to-MSWIFA ratio of 5:2:3.•C–S–H gel and HCC are the main hydration products, enhancing the pore structure.•The new geopolymer has good ability to immobilize heavy metals and chloride ions.
Cement concrete since the early ages has been the most promising building material, but the environmental issue of releasing CO2 into the atmosphere during cement production has prompted researchers ...to look for an alternative in the form of 100 % cementless concrete made out of local waste material that has been enhanced with alumina and silica. This research study was conducted for making the geopolymer with the locally available fly ash with a partial replacement of fine aggregate with plastic waste at 0 %, 5 %, 10 % and 20 %. The microscopic studies of available fly ash were conducted to make a proper geopolymer mix design and tested for the compressive strength of geopolymer concrete at 7 days, 14 days and 28 days. The study was conducted at room temperature of 27 °C along with the elevated temperature of 60 °C, 70 °C, and 80 °C.
The preparation of geopolymer from alkaline solid waste instead of strong alkali presents the disadvantage of low early strength. However, improving the early mechanical properties of the geopolymer ...to meet the engineering requirements is challenging. In this paper, the effects of different moulding pressures and curing methods on the properties of red mud–ground granulated blast furnace slag activated by municipal solid waste incineration fly ash (MSWIFA)–carbide slag (CRMG) were studied and evaluated in terms of compressive strength and XRD, FTIR, SEM, and MIP techniques analysis. The results showed that the moulding pressure of 30 MPa could increase the compressive strength at 3 d by 182% and decrease the porosity from 30.28% to 27.38%. These results are attributable to the fact that the moulding pressure causes the particles to be tightly bound and promotes the geopolymerisation reaction. High-temperature (HT) curing could accelerate the hydration reaction and increase the compressive strength at 3 d by 133.7% and 141.6% compared with those obtained by water curing (WC) and room-temperature (RT) curing, respectively. Microscopic analyses showed that HT curing can promote the generation of C–(A)–S–H gel, geopolymer gel and hydrate calcium chloroaluminate (HCC), fill the pores, and increase the structure's compactness. Finally, the proposed method was verified by synthesising geopolymer pavement bricks (GPB), and the compressive strength at 3 d was found to reach 54 MPa under an optimal curing method (moulding pressure of 30 MPa, 90 °C for 12 h). Compared with concrete pavement bricks, GPB presents broad application prospects for saving economic costs and protecting the environment. The results provide a theoretical basis and technical support for the application of CRMG in rapid demoulding projects such as unfired bricks.
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•CRMG can be applied to rapid demoulding engineerings, such as pavement bricks.•Moulding pressure reduces the total pore volume, but increases the macropore volume.•HT curing promotes the occurrence of hydration reaction and crack propagation.•Moulding pressure and HT curing can effectively improve the early strength.
Management of basic natural resources and the spent industrial and domestic streams to provide a sustainable safe environment for healthy living is a magnum challenge to scientists and ...environmentalists. The present remedial approach to the wastewater focuses on recovering pure water for reuse and converting the contaminants into a solid matrix for permanent land disposal. However, the ground water aquifers, over a long period slowly leach the contaminants consequently polluting the ground water. Synthetic adsorbents, mainly consisting of polymeric resins, chelating agents, etc. are efficient and have high specificity, but ultimate disposal is a challenge as most of these materials are non-biodegradable. In this context, it is felt appropriate to review the utility of adsorbents based on natural green materials such as agricultural waste and restricted to few model contaminants: phenols, and heavy metals chromium(VI), and cadmium(II) in view of the vast amount of literature available. The article discusses the features of the agricultural waste material-based adsorbents including the mechanism. It is inferred that agricultural waste materials are some of the common renewable sources available across the globe and can be used as sustainable adsorbents. A discussion on challenges for industrial scale implementation and integration with advanced technologies like magnetic-based approaches and nanotechnology to improve the removal efficiency is included for future prospects.
•Phenols, Cr(VI) and Cd(II) have hazardous impact on biota and environment.•Agricultural waste materials are effective in adsorbing phenols, Cr(VI) and Cd(II).•Interaction mechanisms governing adsorption on agricultural wastes are elucidated.•Challenges and future prospects of agricultural waste adsorbents are discussed.
A pragmatic shift is ongoing in waste material management and wastewater treatment technology due to the large amount of waste production worldwide and the necessity for cheap adsorbents to reduce ...wastewater treatment costs. Improvements in the circular economy and energy recovery from waste materials is another fast-growing concept for promoting sustainability and a greener environment. This review study endeavours to integrate the concept of wastewater treatment by waste materials (agricultural residue, industrial and municipal waste, organic and inorganic sources) and utilization of the used waste adsorbents for value-added products through further treatment. Although very few experimental studies were performed on this concept, this study summarizes the potential valuable products such as regenerated adsorbents, biofuel, soil amendment supplements and cementitious material by utilizing waste adsorbent. Production mechanisms of valuable products is discussed comprehensively. This review also documents the major emerging contaminants, the diverse waste materials as potential adsorbent candidates and conversion processes from waste into adsorbents. The outcome of this review promotes the utilization of waste into multiple useful products generation which may improve waste management and boost the circular economy. The integrated applications of this review describe the commercial window available to accumulate waste materials for large scale applications. Further, sources of energy and nutrients extracted from waste materials after treating polluted water in industries, municipal units and animal husbandries can be a significant contributor to commercial viability in the future.
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•Potential of biomass waste materials for wastewater treatment.•Suitable conversion processes from waste materials to different adsorbents.•Prospective of adsorbent regeneration cycles.•Production of suitable biofuels from waste adsorbent materials.•Alternative applications of waste adsorbent materials for soil nourishment and cementitious material generation.
With the great progress in human activities and production technologies, the waste inevitably produced causes not only environmental pollution but also resource waste; meanwhile, the mobile and ...portable electronic devices urgently need a distributed and sustainable energy source to ensure their stable operation. Here, the waste pollutants (milk cartons) generated from daily life, commonly associated with environmental concerns, are instead identified as an available resource for preparing an emerging energy harvester (triboelectric nanogenerator, TENG), which can convert ubiquitous mechanical energy into electric power. Consequently, based on the waste material, the initial charge density of the TENG is as low as 0.035 mC m–2, which can be tremendously improved to 1.00 mC m–2 through combining a charge excitation circuit, achieving efficient energy harvesting. In addition, compared to the common dielectric film, the waste material can reduce the cost and simplify the process of the preparation of TENG. This work provides not only an innovative approach to simultaneously realize environmental protection and energy harvesting but also more material choice for the preparation of a low-cost and high-performance TENG.
The construction sector has a significant impact on the environment, contributing significantly to energy consumption, resource depletion, and CO2 emissions. This sector is currently shifting away ...from natural materials and cement in favor of alternative materials, thereby reducing environmental impact and promoting sustainability. Worldwide, enormous quantities of waste materials are generated. Most of these waste materials are hazardous, corrosive, flammable, chemically reactive, incendiary, and infectious and are typically disposed of in landfills, causing environmental pollution and posing health risks. As a result, incorporating waste materials into concrete would be a more prudent course of action. This study collected vast bibliometric data comprising journal articles and review articles from the Scopus database over the last two decades and conducted a scientometric review on waste material utilization in concrete. Scientometric analysis is used to determine the current state of research by analyzing available bibliometric data and identifying related publication areas, sources with the most publications, the most frequently occurring keywords, authors, and papers with the most citations, and states that have made the greatest contribution to the field of waste materials utilization in concrete. Moreover, the most active research areas are identified and discussed. Also, the sustainability aspects of recycling waste materials in concrete are discussed, and finally, future research is proposed. The scientometric review will enable scholars from diverse countries to exchange novel ideas and knowledge, foster research collaboration, and establish joint ventures.
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