Optimization and enhancement of CO2 sequestration in industrial wastes for environmental applications

This paper explores carbon capture and storage (CCS) through carbide lime waste (CLW), a by-product of acetylene production, under different conditions. This process is specifically designed to provide an onsite waste management solution for several industries that can easily be integrated into existing systems. In addition, the effect of the carbonation process on collected solids morphology and average particle size was studied. The structural and chemical characteristics of the carbonated carbide lime samples were investigated using X-ray diffraction, scanning electron microscopy, TGA analysis, and Raman spectroscopy. The effect of carbonation conditions on the total dissolved solids and change in pH was studied. All carbonated products exhibited a calcite crystal structure with a specific morphology at each carbonation condition. High CLW concentration helped to form singular long rods and agglomerated spheroidal particles. In contrast, low CLW concentration promoted truncated prismatic morphology. The maximum pH reduction was honored at the highest CLW to water ratio. In addition, a maximum conductivity reduction of 96.87% was obtained at pH 12.7, and a CLW to water ratio of 1:10. Raman analyzer, X-ray diffraction, and scanning electron microscopy confirmed the minimum CO 2 uptake value for the higher carbide lime to distilled water ratio. This is due to the increase in the concentration of calcium species in the CLW–water mixture, which will form a thin carbonation layer that is distributed among calcium species

Students’ assessment of electronic waste environmental management and sustainability at an emirati federal institution

© Springer Nature Switzerland AG 2020. With the ever-shortening lifespan of electronic devices due to advancements in electronics and attractive consumer designs, a dramatic rise in the electronic waste magnitude has been reported as a severe challenge worldwide. These devices do contain not only valuable recyclable materials but also toxic chemicals which can impose human effects and environmental pollution. This paper investigates the awareness among UAE educated people about the electronic waste magnitude. Regionally, UAE generates 17.2 kg of e-waste per capita every year. It ranks among the highest producers of e-waste in the middle-east. As such, in efforts to develop guide strategies and extend awareness among UAE population, a diagnostic survey was conducted and spread among 562 government undergraduate students (202 males and 360 females). One significant finding revealed that despite only one-quarter of the students are not genuinely aware of e-waste definition and its environmental effects; those who are aware are not effectively practicing appropriate e-waste disposal potentially due to the lack of motivation and willingness. Finally, recommendations for engaging students in environmental sustainability through in-campus standards and operations are followed

Integrated mixing machine for sulfur concrete production

The production of sulfur concrete (SC) from its ingredient materials requires controlled heating and mixing conditions at a temperature level of 130°-150 °C. Although this process considered to be common and applicable at the industrial level, it is difficult at the laboratory/research level. This paper presents the design and manufacturing details of a relatively inexpensive laboratory machine for heating and mixing sulfur concrete. The different components of the machine are described in detail to help researchers to produce high-quality sulfur concrete. In this work, the quality of the machine is verified through experimental testing of the physical and mechanical properties of different prepared SC mixtures. Thus, the homogeneity and mixing efficiency required a certain level of workability, and the full controlling of temperature during the production process has been realized. The machine is proven to be efficient, safe, and durable. The comparative study on the physical and mechanical properties of the prepared SC relative to other SC of the same ingredients but heated and mixed through other small-scale machines, showed the superiority of the mixing machine in the production of high strength concrete

Carbon dioxide uptakes by acetylene by-products through gas–solid and gas–solid–liquid reactions

In this work, carbon dioxide uptake value by acetylene by-products was evaluated through two types of carbonation reactions. In the first reaction, solid acetylene by-products were reacted with a simulated effluent CO2 gas (10% CO2 and 90% air) and the maximum uptake value of carbon dioxide per unit mass of reacted solids was calculated. In the second reaction, the mixed solid acetylene by-product with distilled water at a specific mass to volume ratio was reacted with the same effluent CO2 gas to compare the maximum CO2 uptake value with the first reaction. It was found that a superior CO2 uptake in the case of G-S-L reaction with a value of 0.34 g CO2/g ABP over that found in the case of G-S system of 0.14 g CO2/g ABP. The fresh (unreacted) and treated acetylene by-products from both reactions were analyzed to study the effect of carbonation process on solids morphology, average particle size and carbon content. The structural and chemical characteristics of the fresh and carbonated acetylene by-products were investigated using X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. The fresh acetylene by-products showed a major structure of portlandite crystals. All carbonated products exhibited a calcite crystal structure but with different morphology and particle size for each specific chemical reaction

Sustainable Concrete Using Industrial By-product Waste

Alternatives to normal concrete (NC) have been investigated heavily in the last decade, Sulfur concrete is one of the promising substitutes as it works as a binder that replaces the use of cement and water to form a more sustainable option. The objective of this case study was to investigate the effect of using carbide lime waste as aggregate to produce sulfur-based concrete. To achieve this, characterization of the mix components was done after that the mechanical properties of sulfur concrete proportioned with various aggregate types were evaluated. Results revealed that the use of fillers enhanced the properties of the mix and that the mix illustrated superior mechanical properties. Moreover, the study recommended further research to prove the durability of the mix

Production of durable and cost effective sewer pipes using petroleum and industrial waste by-products

© The Authors, published by EDP Sciences, 2017. The Arabian Gulf environment has an adverse impact on concrete structures because of the high ambient temperature, humidity, salt contaminated dust, sea water and underground salts. As an innovative solution, reinforced modified sulfur concrete (MSC) pipes are recognized as a durable and economical solution for deterioration of pipelines. This work describes the manufacture and characterization of new MSC based on a cost effective sulfur modification process. Bitumen, a by-product from crude oil refining process was used to modify elemental sulfur and enhance its physical, mechanical properties, and mostly to increase its corrosive resistivity. The study has focused on optimizing the proportions of an offered MSC mixes that are composed of modified sulfur (MS) as a binder, crushed sand, dune sand and ladle furnace (LF) slag as aggregates, and ground granulated blast furnace slag (GGFBS) as a filler. To maximize the physical and mechanical properties of MSC sewer pipes, different mixtures were prepared and investigated. The optimum mix of MSC has a maximum compressive strength of 64 MPa, maximum splitting tensile strength of 4.5 MPa, maximum flexural strength of 21 MP, with a high corrosion resistance in acidic and salty environments

CO\u3csub\u3e2\u3c/sub\u3e sequestration using accelerated gas-solid carbonation of pre-treated EAF steel-making bag house dust

© 2015 Elsevier Ltd. Mineral CO2 sequestration is a promising process for the reduction of carbon dioxide emissions to the atmosphere. In this paper, alkaline calcium-rich dust particles collected from bag filters of electric arc furnaces (EAF) for steel making were utilized as a viable raw material for mineral CO2 sequestration. The dust particles were pre-treated through hydration, drying and screening. The pre-treated particles were then subjected to direct gas-solid carbonation reaction in a fluidized-bed reactor. The carbonated products were characterized to determine the overall sequestration capacity and the mineralogical structures. Leaching tests were also performed to measure the extracted minerals from the carbonated dust and evaluate the carbonation process on dust stabilization. The experimental results indicated that CO2 could be sequestered using the pre-treated bag house dust. The maximum sequestration of CO2 was 0.657kg/kg of dust, based on the total calcium content. The highest degree of carbonation achieved was 42.5% and the carbonation efficiency was 69% at room temperature

Durability of modified sulfur concrete in sewerage environment

This study verifies and validates the superiority of sulfur concrete (SC) over the ordinary Portland cement concrete (PCC) and sulfate-resistant concrete (SRC) in sewer harsh environments. A field study was performed in an actual sewage environment, specifically at the sewer’s gas and sludge environments. Performance of the PCC, SRC and two types of SC was assessed after 3, 6, 10, 18 and 24 months of exposure. Specimen’s durability was evaluated through physical appearance, change in weight and mechanical and hydraulic properties. The microstructure and the composition of the specimens were studied by means of scanning electron microscopy and X-ray diffraction. Attempts have been made to explain the mechanism of deterioration, the basic chemical interactions involved in the deterioration processes and the effect of such interactions on the concrete and reinforcing steel. It was found that SC is highly resistant to sewer environment compared to PCC and SRC, and that there was a significant weight loss of 8·0% and 13·6% in PCC and SRC, respectively, whereas a smaller weight loss of 2·2% was noticed in SC. This is consistent with the observed reduction in strength, increase in permeability and noticeable steel bar corrosion for the PCC and SRC relative to the SC

Bio-regeneration of activated carbon: A comprehensive review

© 2018 Elsevier B.V. The use of microorganisms to regenerate activated carbon (AC), bio-generation, can avert costly and logistically challenging ex-situ steam regeneration of carbon normally required to recover its adsorptive capacity. Bio-regeneration employs microbial metabolism in which the microbes use the available organic substrates (contaminants) to generate energy. During this process, they generate equivalent protons and electrons, which are transferred to the substrates to finally break them down to simpler molecules or ions, such as CO2, methane and Cl−. The optimal microbial conditions depend on the temperature, available nitrogen and phosphorus levels, dissolved oxygen levels, and microbe/substrate stoichiometric ratios and the residence time of the AC particles within the reactor. In this review, the authors highlight the most recent development in bio-regeneration including the regeneration mechanism, the relationship between the reversibility of adsorption and the efficiency of bio-regeneration, the general aspects affecting bio-regeneration, the principle and target compounds for bio-regeneration, different established methods for quantifying the bio-regeneration and the efficiency of bio-regeneration. Few case studies of bio-regeneration of activated carbon loaded with different contaminants are presented. Research on microbiology regeneration has gained considerable attention in recent years, but it still needs more contribution from other disciplines including process engineering, biochemistry and material sciences for optimizing the process performance

E-Waste Recycling Behavior in the United Arab Emirates: Investigating the Roles of Environmental Consciousness, Cost, and Infrastructure Support

This study examines whether consumers’ behavior affects e-waste recycling in the UAE. This paper provides a theoretical model of e-waste recycling behavior based on the theory of planned behavior (TPB), and it goes on to analyze the impact of environmental consciousness, infrastructural support, and costs in e-waste recycling. To assess this study’s constructs, a survey instrument is created. The theoretical model is tested using data gathered from a survey of UAE residents. PLS-SEM (partial least squares structural equations modeling) is used to assess the data. The results support the use of the TPB in the e-waste recycling behavior context. Furthermore, this study shows intriguing findings regarding the effect of environmental consciousness, perceived infrastructural support, and the cost of e-waste recycling. Environmental consciousness shows a positive moderation effect on the association between e-waste recycling attitudes and intentions. This finding implies that the environmental consciousness of residents should be increased to translate e-waste recycling intentions into behavior. Environmental consciousness can be enhanced through training programs. Furthermore, special sustainability courses in higher education that focus on improving environmental awareness among students will have a lasting impact. This study supports the positive moderation effect of perceived infrastructure support on the association between recycling intentions and behavior