Metakaolin Clay Research Articles

Kinetic & thermodynamic studies of green fuel additive solketal from crude glycerol over metakaolin clay catalyst

Biodiesel synthesis produces about 10 % glycerol as a byproduct, prompting environmental concerns. The utilization of crude glycerol into valuable products requires an Eco-friendly technique. This study depicts glycerol acetalization using acetone and novel catalyst acid-treated metakaolin clay. Raw kaolin clay was calcined at 600 °C and treated with acid at 102 °C for 3 h. Afterward, acid activated clay was filtrate and dried in oven to remove moisture content. The catalyst prepared with a 5 M solution of sulfuric acid exhibited the highest surface area of 82.33 m2. g−1 and gave the highest yield (80 %) of Solketal with 73 % of glycerol conversion under optimum conditions. The ketalization reaction of Solketal synthesis was studied in terms of thermodynamics and kinetics. A Langmuir-Hinshelwood rate expression based on two-parameter kinetic law was used in this study. From the kinetic studies, activation energies (EA) of forward and backward reactions were found to be K1 = 39.23 kJ. mol−1 and K2 = 35.70 kJ. mol−1 respectively. Furthermore, reaction was exothermic having an enthalpy of ΔHo = −18.86 kJ. mol−1 and the entropy ΔSo = −0.1 kJ. mol−1 calculated from this process. Solketal derived from sustainable sources such as bio-glycerol and biomass-based acetone, has a wide range of uses as fuel additives and medicines industry. This research marks a significant advancement in the development of a continuous synthesis technique for Solketal and its recovery from glycerol-acetone mixtures.

Experimental Investigation Properties of Reinforced Cement Concrete with Partial Replacement of Cement by Metakaolin Clay and Structural Health Monitoring Using Sensor

Abstract: Cement concrete is the most extensively used construction material. Maintenance and repair of concrete structures is a growing problem involving significant expenditure. As a result carried out worldwide, it has been made possible to process the material to satisfy more stringent performance requirements, especially long–term durability. HPC is the latest development in concrete. It has become very popular and is being used in many prestigious projects such as Nuclear power projects, flyovers multi-storeyed buildings. When using HPC, the addition of supplementary materials in cement has dramatically increased along with the development of concrete industry, due to the consideration of cost saving, energy saving, environmental concerns both in terms of damage caused by the extraction of raw materials and carbon dioxide emission during cement manufacture have brought pressures to reduce cement consumption. Metakaolin looks to be a promising supplementary cementations material for high performance concrete. Properties of concrete with metakaolin is mostly preferred additives in high performance concrete. A possible lower cost, due to large availability in our country itself may be advantages to metakaolin usage in HPC. The substitution proportion of metakaolin is to be used was 5%, 10%, 15%, 20% by the weight of cement. To make this cubes and cylinders to determine the strength and durability of concrete of it. A multitude of structural health monitoring options are currently being investigated to address the reliability of concrete infrastructures at different stages of their service life. This review presents the recent achievements in the field of sensors developed for monitoring the health of concrete infrastructures. The focus of this review is on sensors developed for monitoring parameters including temperature, humidity, pH, corrosion rate, and stress/strain and the sensors particularly fabricated based on fiber optic, Bragg grating, piezoelectric, electrochemical, wireless and self-sensing technologies. Several examples of developed concrete monitoring sensors (from laboratory concepts to commercialized products) together with their various benefits and drawbacks as well as open research problems will be discussed in this project.

Simple Approach in Measuring the Synthesized Zeolite from Kaolin as Nutrient Retention for Mung Bean Growth

Since the 1960s, zeolites mesoporous structures have been employed in agriculture due to their efficiency as soil modifiers for plant growth that can retail minerals and important nutrients as well as cation exchange capacity (CEC). This characteristic iscritical in ensuring that plant growth is not hampered by the elimination of minerals and nutrients from the fertilizer; thus, zeolite materials are always referred to as slow-release or slow retention of fertilizer. The purpose of this study is to evaluate the performance of kaolin-synthesized zeolites as controlled release fertilizers to reduce soil nutrient leaching. The zeolite Linde-type A used in this study was produced by hydrothermal synthesis from metakaolin clay (thermal treatment). This study's metakaolin clay was made through thermal treatment (calcination) of kaolin clay heated at 650 °C for 24 hours. X-ray diffraction (XRD) was used to determine that the phase of the synthesized zeolite was of the LTA type. Anexperiment isconducted to examine the effects of zeolite on the trapping and sustaining of NPK fertilizer for plant growth. Compared to standard NPK fertilizers without zeolite, the fertilizer containing zeolite accelerated the growth of mung bean plants by 35.5% for stem height and 52.5% for leaf length. This study indicated that zeolite has a strong capability for retaining minerals and nutrients, guaranteeing that plant growth is not inhibited by nutrient deficiency.

Barrier Corrosion Protection Properties of Metakaolin Clay-Kadilux Epoxy Coatings on Galvanized Steel

Epoxy polymer, an illustrious barrier corrosion protective coating, was reinforced with metakaolin clay, an eco-friendly inorganic filler to enhance the barrier corrosion protection properties in water and in acidic environment on galvanized steel plates. Various proportions 0, 1, 3, 5, and 7 wt.% of metakaolin fillers were mixed intrinsically with kadilux epoxy and characterized for thermal stability, water absorption according to ASTM G31, and acid immersion according to ASTM D-570 standards, respectively. The reinforced coatings minimized the pore size and density, lower water absorption, and better acid resistance properties especially at 7 wt.% of the fillers. The thermal stability of the films improved beyond 5 wt.% of filler composition.

Activation of Nano Kaolin Clay for Bio-Glycerol Conversion to a Valuable Fuel Additive

High production of biodiesel results in a surplus of glycerol as a byproduct that leads to a drastic decline in the glycerol price as well as overall biodiesel production. Alternative methods must be introduced for the economical process for biodiesel production via utilization of crude glycerol into valuable chemicals or fuel additives. This study introduces an ecofriendly process of solketal synthesis from glycerol and acetone in the presence of a novel metakaolin clay catalyst, which is a useful additive in biodiesel or gasoline, in order to enhance the octane number and to control the emissions. Moreover, kaolin clay catalysts are low cost, abundantly available, eco-friendly and one of the more promising applications for solketal synthesis. In this study, raw kaolin clay was activated with an easy acid activation technique, modification in physicochemical and textural properties were determined by using X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) and Field Emission Scanning Electron Microscope. Among all acid-treated catalysts, metakaolin K3 have shown best catalytic properties, high surface area and pore size after acid activation with 3.0 mol/dm3 at 98 °C for 3 h. Acetalization of glycerol with acetone carried out in the presence of an environmentally friendly and inexpensive novel metakaolin K3 catalyst. The maximum yield of solketal obtained was 84% at a temperature of 50 °C, acetone/glycerol molar ratio 6/1 and for 90 min with novel metakaolin clay catalyst. Effect of various parameters (time, temperature, acetone/glycerol molar ratio, catalyst loading) on the solketal yield and glycerol conversion was discussed in detail. This approach offers an effective way to transform glycerol into solketal—a desirable green chemical with future industrial applications.

Vipulanandan Constitutive Models to Predict the Rheological Properties and Stress–Strain Behavior of Cement Grouts Modified with Metakaolin

Abstract In this study, the effects of metakaolin clay (MK) on the rheological properties, setting time, compressive strength, and toughness of cement grouts with water-cement ratios (w/c) of 0.6 and 1.0 were investigated. Based on the information in the literature, the amount of MK used in various mix designs varied up to 10 % by the weight of cement. The compressive stress–strain behavior of cement grout modified with MK was investigated up to 90 days of curing. The addition of 10 % of MK increased the apparent viscosity of the cement grout from 20 cP to 62 cP and from 13 cP to 44 cP with w/c ratios of 0.6 and 1, respectively. Setting time of cement grout mixes with a w/c ratio of 1.0 had longer initial and final setting times than the grout mixes with a w/c ratio of 0.6. The addition of 10 % MK increased the compressive strength of the cement grouts with w/c ratios of 0.6 and 1 from 8 MPa (1,175 psi) to 30.1 MPa (4,366 psi) and from 2.4 MPa (348 psi) to 17.8 MPa (2,582 psi) after 90 days of curing, respectively. The addition of 10 % MK increased the toughness of the cement grouts with w/c ratios of 0.6 and 1 from 1.42 J·m−3 to 2.27 J·m−3 and from 0.94 J·m−3 to 1.38 J·m−3 after 90 days of curing, respectively. The Vipulanandan p–q model was used to predict the changes in stress-stain behavior with curing time. The Vipulanandan rheological model also has a limit on the shear stress were as the other model did not have a limit. Based on the Vipulanandan rheological model, the maximum shear stresses produced by the portland cement grouts with w/c ratios of 0.6 and 1 with 0 MK were 58 Pa and 33 Pa, respectively. The addition of 10 % MK to the Portland cement (PC) grouts increased the maximum shear stresses by 155 % and 136 % for w/c ratios of 0.6 and 1, respectively.

Preparation of geopolymer concrete using Egyptian kaolin clay and the study of its environmental effects and economic cost

Concrete is the basic building material in the world, and cement is the main material used in the production of concrete. However, there is an urgent need to reduce the consumption of cement, where cement production leads to 5–8% of global emissions of carbon dioxide. Geopolymer concrete is an innovative building material produced by alkaline activation of pozzolanic materials such as fly ash, granulated blast furnace slag, and kaolin clay. Geopolymers are widely used in the production of geopolymer concrete due to their ability to reduce carbon dioxide emissions and reduce high energy consumption. During the present study, the environmental impact of two strength grades (30 MPa and 40 MPa) of metakaolin geopolymer concrete (GPC) was evaluated to study its applicability in the construction sector. The kaolin clay extracted from the Aswan quarries was activated by a mixture of sodium hydroxide and sodium silicate solution. To introduce geopolymer concrete in the Egyptian industry sector, its environmental performance, together with its technical performance, should be competitive to the cement concrete used mainly for the time being. The cost of this new concrete system should also be evaluated. The environmental impact of GPC was evaluated and compared with cement concrete using life cycle assessment analysis and IMPACT 2002+ methodology. The cost of production was calculated for 1 m3 of geopolymer concrete and conventional cement concrete. Metakaolin geopolymer concrete achieved a high compressive strength of ~ 56 MPa, splitting tensile strength of 24 MPa, and modulus of elasticity of 8.5 MPa. The corrosion inhibition of metakaolin geopolymer concrete was ~ 80% better than that of conventional cement concrete. Geopolymer concrete achieved a reduction in global warming potential by 61% and improved the human health category by 9.4%. However, due to the heavy burdens of sodium silicate, the geopolymer concrete negatively affected the quality of the ecosystem by 68% and showed a slightly higher impact than cement concrete on the resource damage category for low strength grade of 30 MPa. The high cost of the basic ingredients of the geopolymer resulted in a high production cost of geopolymer concrete (~ 92 US$) that was three times that of cement concrete (~ 31 US$). Based on the environmental results, geopolymer concrete based on locally available metakaolin clay can be applied in the construction sector as a green alternative material for cement concrete.

Alkali activated clay of moderate kaolin content

Metakaolin clay of 30% reactive silica was alkali activated by blends of sodium silicate and sodium hydroxide using Na2O/Al2O3 = 1.2 to 1.7 and H2O/Na2O = 10 to 6. at room temperature. The geopolymer pastes obtained was investigated for durations up to one year. In spite of the relatively low SiO2/Al2O3 ratio of 2.06, 3 days and one year strength of 39 and 80 MPa are obtained at Na2O/Al2O3 = 1.4 and H2O/Na2O ~ 8. A successful prototype of geopolymer concrete building was realized to introduce the geopolymer application in Egypt. A geopolymer concrete foundation with 3-days and 28-days strength of 11 and 35 MPa was achieved with lower ratios than those used in the pastes and an with increased amount of water to insure the workability. The results are good reference for the achievement of geopolymer construction of better properties in the future, in Egypt.

English

Metakaolin clay (MC)-based geopolymer was used to immobilise waste cathode ray tube (CRT) glass as a method of recycling it into other useful products. Effects of CRT glass on the properties of geopolymer and toxicity status were assessed. A Nigerian MC was replaced with different proportions of ground waste CRT glass (0-20%) and alkali-activated to produce geopolymers. X-ray fluorescence (XRF) was used to characterise CRT and MC. The geopolymers were cured at room temperature for 7, 14, 21 and 28 days. Their setting time, compressive strength, dry density, water absorption and Pb binding abilities were evaluated. Geopolymers were leached using Toxicity Characteristics Leaching Procedure (TCLP). The XRF results revealed the main oxides of MC as SiO2 and Al2O3 and CRT glass as SiO2 and PbO. Setting time of the geopolymers ranged from 1 h (0% CRT) to 2 h (20% CRT). Compressive strength values of the geopolymers increased with percentage composition of CRT glass and curing age. At 28 days, the maximum compressive strength of 36.8±0.4 MPa was obtained for geopolymer that contained 20% CRT glass. Increase addition of CRT glass reduced water absorption and increased the density of the geopolymer. Leachable Pb in the geopolymer extracts was below US EPA TCLP regulatory limit of 5 mg/L. Metakaolin clay geopolymers can be a cost-effective and sustainable binder to recycle CRT into value added products. Key words: Metakaolin clay geopolymer, Immobilisation, cathode ray tube glass, recycling, leachable Pb.

Degradation behavior and kinetics of sisal fiber in pore solutions of sustainable cementitious composite containing metakaolin

Degradation of cellulose is the primary cause for the premature failure of natural fibers in the alkaline environment of cementitious systems. However, the degradation behavior and kinetics of cellulosic fibers in cementitious composites have not been thoroughly understood. In this study, the aging kinetic of cellulose exposing to pore solutions of cementitious materials is experimentally investigated and a model for service-life prediction of cellulose in cement is developed. To assess the impact of cement hydration on degradation behavior of cellulosic fibers and understand the correlations between fiber degradation and alkaline environment of cement, an approach to directly assess degradation rate of the embedded fibers was developed by determining fiber's tensile properties, thermal decompositions, crystallinity, and microstructures. The results indicate a strong dependence of degradation of sisal fiber on alkalinity of cement pore solutions. By incorporating 30 wt% metakaolin clay, the hydration of cement was modified and a mild environment was generated. Concentration of OH− was reduced and the pore solution becomes from oversaturated to unsaturated for calcium hydroxide after 7 days. As a result, tensile strength loss of the aged fiber was mitigated and the service life of cellulose was extended by 13.7 times.

Study of mechanical and microstructural properties of geopolymer concrete with GGBS and Metakaolin

Geopolymers are a new type of artificial polymer which is developed when an aluminosilicate source is triggered or activated by the application of alkaline hydroxide and silicate solution. They have shown good mechanical properties and shows good resistance to chemicals, lesser shrinkage, no damage to environment and shows formidable durability. Ground granulated blast furnace slag(GGBS) is a good aluminosilicate source as it contains high amounts of alumina and silica which are necessary for the geopolymerisation reaction to take place. In this paper, three variations in terms of weight percentages of GGBS and metakaolin clay have been taken with 80%-20%,50%-50%, and 20%-80% respectively. A 10M solution of sodium hydroxide with sodium silicate was used as alkaline activator solution. For practical purposes ambient curing of the geopolymer samples has been adopted. The Degree of reaction was evaluated for all the percentage variations of the geopolymer concrete at 7 days of curing. The mechanical properties of geopolymer concrete have been studied by compressive test, split tensile test and four-point loading test. To understand the structural integrity of the casting of the geopolymer specimens, ultrasonic pulse velocity test was performed. The study of micro-structure of geopolymer concrete was carried out by Fourier transform infrared spectroscopy (FTIR) technique.

Effect of Sodium Hydroxide and Mould Shape in Geopolymer Fabrication Made With Synthesised Local Clay for Water Filtration

The preparation and testing of geopolymer ceramic membranes for water separation is presented. Geopolymers are typically used in refractories and as precursors to ceramic formation, allowing the production of ceramic-like materials with low temperature processes. A new geopolymer material was synthesized using local clay from Sabah, Malaysia and its filtration performance was compared to a commercial clay fabrication. The synthesized formulation of geopolymer ceramic paste was made by mixing local metakaolin clay as a source of aluminosilicate with alkaline solution, and then curing in a sealed environment. The amorphous paste was crushed and moulded prior to firing at an elevated temperature up to 700C. The feasibility of this laboratory-fabricated geopolymer for water filtration applications was studied by evaluating its performance at different thicknesses and mould shapes of fabricated membrane using 8 to 16 Molar natrium hydroxide (NaOH) as the alkali activator in the synthesis of the geopolymer. The result found that increased molarity of sodium hydroxide results higher compressive strength and affect filtration rate. Improved filtration performance (subject to the shape and width of the geopolymer membrane) was found by analysis and separation rates of 47% for blue dye colour and 88% for turbidity were achieved when operated without pressure or pump.