Magnesium Potassium Phosphate Cement Research Articles

Mix design and rheological properties of magnesium potassium phosphate cement composites based on the 3D printing extrusion system

The magnesium potassium phosphate cement composites (MPCCs) with rapid setting, high early strength and low shrinkage performances show considerable potential for 3D printing. In this study, the synergistic effects of magnesium to phosphate (M/P) mass ratio, borax content and fly ash content on the the initial setting time and rheological properties of 3D printed MPCCs (3DP-MPCCs) were investigated using response surface methodology (RSM). The dynamic yielding behaviours are obtained based on Herschel-Bulkley model. The effects of mix design on deformation rate and compressive strength of 3DP-MPCCs were discussed. The results showed that the initial setting time of 3DP-MPCCs was prolonged to 30 min to 90 min by optimizing the mix design and decreased with the increase of M/P mass ratio. The incorporation of borax significantly reduced the consistency factor, which was beneficial to the extrudability of 3DP-MPCCs. High M/P mass ratio was the critical factor for the better buildability of 3DP-MPCCs, which can be further improved by increasing the FA content. Finally, the 3DP-MPCCs with M/P mass ratio of 3.0, 40% borax and 25% FA was determined as the optimal mix design, showing the minimum deformation rate of 0.28% and highest compressive strength of 32.59 MPa, respectively.

Effect of water content on microstructure and properties of magnesium potassium phosphate cement pastes with different magnesia‐to‐phosphate ratios

AbstractMagnesium potassium phosphate cement (MKPC) is a class of chemically bonded ceramic for special engineering applications. The selection of mass ratios of MgO‐to‐KH2PO4 (M/P) and water‐to‐cement (W/C) is an important aspect for formulating MKPC paste. This paper analyzed the stoichiometry of the primary reaction of MKPC and investigated the effect of W/C (0.14–0.40) on paste microstructure and properties at different M/P (1.5–4). At high M/P, low W/C was sufficient to complete the hydration of KH2PO4 and higher W/C yielded looser microstructure, dictating that properties of high M/P pastes were monotonic functions of W/C. However, a clear W/C threshold effect was found in medium M/P pastes at both micro‐ and macro‐levels. Low W/C below stoichiometric value suppressed the formation of K‐struvite and favored the presence of an amorphous phase, leading to intense early shrinkage, low early compressive strength, and poor long‐term water resistance. The increase in W/C above stoichiometric value resulted in the segregation of excess water and thus to porous structure, with detrimental effects on dimensional stability and strength. The micro–macro analysis highlighted the importance of stoichiometric water amount in the optimal design of MKPC.

Assessment of magnesium potassium phosphate cement for waste sludge solidification: Macro- and micro-analysis

The feasibility and performance of eco-friendly and sustainable magnesium potassium phosphate cement (MKPC) to solidify urban river sludge are innovatively evaluated. To probe exhaustively into the mechanical performance and micromechanism of MKPC solidified dredged sludge, the effect of binder content, Mg/P molar ratio, retarder (borax) content and curing age are analyzed through unconfined compressive strength (UCS), mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests. The experimental findings indicate the compressive strength is raised owing to an increase in MKPC amount and curing age. The isolation effect of sludge matrix weakens the retarding effect of borax, but reasonable borax content is beneficial to the strength improvement at longer curing age. The UCS of solidified samples with lower molar ratio (Mg/P = 3) increases rapidly at the early age while limitedly in later stage. The UCS reaches the maximum at the molar ratio of Mg/P = 4–5. The XRD and MIP analysis demonstrates that MgKPO4·6H2O (struvite-k) is the major hydration phase produced along with unreacted dead burned magnesia. Struvite-k can effectively fill the large pores (1–10 μm) and cause the transformation of large pores into small pores (0–0.1 μm), which has a good refinement performance for pore structure. The SEM images show that the prismatic or layered struvite-k forms preferentially and its final morphology is intimately connected with the Mg/P molar ratio. When the MKPC dosage and curing age increase, the struvite-k crystals are significantly densified and some microcracks appear due to the surface tension effect during the hydration heat-associated dehydration in crystal growth process. The synthesized crystal is fully developed and the crystal grows more completely under appropriate reaction conditions and reasonable relative concentration of reactants, which produces stronger interconnection between sludge particles and denser microstructure within matrix, contributing to the strength development of solidified sludge. In summary, the mechanical, eco-friendly and cost-efficient benefits could be highly anticipated from substituting MKPC for Portland cement (PC) in sludge solidification.

Effect of temperature curing on properties and hydration of wollastonite blended magnesium potassium phosphate cements

K-struvite, the main hydrate of magnesium potassium phosphate (MKP) cements, dehydrates at ~50 °C, thus elevated temperatures at service conditions could affect cement properties and durability. In this study, properties and hydration of MKP cement without and with wollastonite were investigated at 20 and 50 °C. In hydrated pure MKP cement K-struvite decomposes progressively over time to MgKPO4·H2O at 50 °C, which leads to a strong reduction of solid volume and severe strength loss. The presence of wollastonite significantly slows down the decomposition rate of K-struvite, which is still observed after 393 days at 50 °C. K-struvite together with amorphous hydroxyapatite, M-(C)-S-H and CaK3H(PO4)2 from the wollastonite reaction result in a cement with good short and long-term strength at both 20 and 50 °C.

Early age hydration and application of blended magnesium potassium phosphate cements for reduced corrosion of reactive metals

Magnesium potassium phosphate cements (MKPC) were investigated to determine their efficacy towards retardation of reactive uranium metal corrosion. Optimised low-water content, fly ash (FA) and blast furnace slag (BFS) blended MKPC formulations were developed and their fluidity, hydration behaviour, strength and phase assemblage investigated. In-situ time resolved synchrotron powder X-ray diffraction was used to detail the early age (~60 h) phase assemblage development and hydration kinetics, where the inclusion of BFS was observed to delay the formation of struvite-K by ~14 h compared to FA addition (~2 h). All samples set within this period, suggesting the possible formation of a poorly crystalline binding phase prior to struvite-K crystallisation. Long-term corrosion trials using metallic uranium indicated that MKPC systems are capable of limiting uranium corrosion rates (reduced by half), when compared to a UK nuclear industry grout, which highlights their potential application radioactive waste immobilisation.

Influence of carbonation curing on hydration and microstructure of magnesium potassium phosphate cement concrete

Magnesium phosphate cements are normally referred as chemically bonded ceramic materials and have a vast range of potential applications, due to their excellent performance. This study aims to investigate the effects of carbonation curing on hydration and microstructure of magnesium potassium phosphate (MKPC) concrete. Concrete specimens were prepared and cured in ambient as well as carbonation curing environment. The performance of MKPC concrete specimens were examined via compressive strength and nano indentation tests. In addition, microstructure, and hydration products of MKPC specimens on carbonation curing were investigated via Backscatter electron microscopy (BSEM), Energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Thermogravimetric analysis (TGA). Experimental results show that the MKPC concrete with carbonation curing represents increased mechanical properties compared to uncarbonated MKPC concrete specimens. The results also showed that the production of magnesium carbonate like Nesquehonite under carbonation had a filling effect that refined the microstructure and enhanced the mechanical properties of the composites.

Development of a stoichiometric magnesium potassium phosphate cement (MKPC) for the immobilization of powdered minerals

Ordinary Portland Cement (OPC)-based materials are not systematically adapted for immobilizing industrial hazardous waste, e.g. for aluminium powder or plutonium waste sludge. In such case, Magnesium Potassium Phosphate Cements (MKPC) represent an interesting alternative.The originality of this research is to develop a formulation of a MKPC paste for hazardous waste immobilization, which incorporates a maximum amount of such waste, preferably in powdered form. To this purpose, a stoichiometric MKPC paste is selected, and its properties are improved by powdered waste addition.Firstly, the physico-chemical mechanisms generating expansion in stoichiometric MKPC paste are analyzed. Swelling is attributed to a pH gradient in the paste, due to the progressive sedimentation of MgO particles in the fresh mix.Secondly, over-stoichiometric MgO is replaced by varying amounts of minerals simulating the waste, of different mineralogy and granulometry, in order to achieve sufficient workability and no swelling. An optimal formulation is proposed, which incorporates powdered fly ash at a fine-to-cement mass ratio (F/C) of 1. Its mechanical performance and endogenous dimensional changes are comparable to typical over-stoichiometric pastes, and they stabilize between 7 and 28 days.

Effect of mixture proportioning on the strength and mineralogy of magnesium phosphate cements

Magnesium potassium phosphate cement (MKPC) has properties advantageous over ordinary portland cement such as quick setting and rapid strength gain. Although the effect of mixture proportioning on MKPC pastes has been studied, there are conflicting reports on how calcination of magnesia, parameters like magnesium-to-phosphate ratio (M/P) and water-to-binder ratio (W/B), added materials like borax and fly ash, or the addition of sand influence mineralogy and properties like setting and strength. These factors are evaluated over a practical range of values for each using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy on paste samples. Strength development is evaluated using both pastes and mortars. Calcination of magnesia forms some forsterite with impurity SiO2 which may be linked to the reduction of reactivity. Increasing W/B increases setting time more significantly at lower M/P. Increasing M/P increases early strength but not so much ultimate strength. The main final phases in the pastes are K-struvite and unreacted MgO. Addition of borax or low-lime fly ash does not alter the mineralogy of hydrated pastes. Varying M/P simply changes the relative amounts of these solid phases. Unlike in Portland systems, adding up to ~60 vol% sand to pastes does not decrease strength considerably.

Nanoscale insight on the initial hydration mechanism of magnesium phosphate cement

The hydration rate, microstructure, mechanical properties and durability of Magnesium phosphate cement (MPC) prepared by different kinds of phosphates are quite different. These differences in macroscopic properties are essentially determined by microscopic chemical reactions. Therefore, in this paper, the adsorption mechanism of MgO interface to water and ions in the initial hydration process of MPC and the hydration structure of different ions were discussed at the molecular level. Herein, the structure and dynamics properties of water, NH4+, Na+, K+ and Cl− ions at MgO interface were analyzed by molecular dynamics method. The results show that the water molecules near the MgO interface can be connected to the matrix oxygen through hydrogen bonding and have a Coulomb interaction with the Mg on the interface. Therefore, the water molecules accumulate and stratify at the interface and the density distribution curve of water molecules forms a peak near the interface. This explains the stage of MgO adsorption of water molecules during the initial hydration of MPC. Besides, a large amount of ammonium ion, sodium ion and potassium ion are adsorbed on the MgO surface, and the cation density distribution curve also forms a peak near the interface. In addition, the radius of sodium ion is smaller and the Na-Os bond is stronger than that of NH4+ and K+ (Os represents the oxygen atom in MgO). Hence, the number of sodium ions adsorbed to the interface is the largest, the radial distribution function (RDF) of Na-Os forms a high-strength and sharp peak, The Os coordination number of Na+ is more than that of NH4+ and K+. This also explains the experimental phenomenon that sodium magnesium phosphate cement has a faster hydration rate and shorter setting time than ammonium magnesium phosphate cement and potassium magnesium phosphate cement. Due to the adsorption of the interface, the mean square displacement of cations has decreased to some extent compared with that in the corresponding pure solution models. This study provides a basic understanding of the initial hydration mechanism of MPC at the molecular level.

Magnesium potassium phosphate cements to immobilize radioactive concrete wastes generated by decommissioning of nuclear power plants

This paper evaluates the efficacy of magnesium potassium phosphate cements (MKPCs) as waste forms for the solidification of radioactive concrete powder wastes produced by the decommissioning of nuclear power plants. MKPC specimens that contained up to 50 wt% of simulated concrete powder wastes (SCPWs) were evaluated. We measured the porosity and compressive strength of the MKPC specimens, observing them using scanning electron microscopy and X-ray diffraction. The addition of SCPWs reduced the porosity and increased the compressive strength of the MKPC specimens. Struvite-K crystals were well-synthesized, and no additional crystal phase was formed. After thermal cycling and after immersion, MKPC specimens with 50 wt% SCPWs satisfied the waste-acceptance criteria (WAC) for compressive strength. Semi-dynamic leaching tests were performed using the ANS 16.1 method; the leachability indices of Cs, Co, and Sr were 11.45, 17.63, and 15.66, respectively, which also satisfy the WAC. Thus, MKPCs can provide stable matrices to immobilize radioactive concrete wastes generated by the decommissioning of nuclear power plants.

Effects of K-struvite on hydration behavior of magnesium potassium phosphate cement

Increasing the amount of final hydration products of magnesium potassium phosphate cements (MKPC) can improve its mechanical properties and increase its application diversity. This work investigates the influence of the MgKPO4·6H2O (K-struvite) on the hydration behavior and mechanisms of MKPC with Mg/P ratio of 6 at w/c ratio of 0.3. The results indicate the number of exothermic peaks decreases with addition of K-struvite, besides, the hydration heat of MKPC increases first and then decreases compared with MKPC without K-struvite. At w/c ratio of 0.3, traces of K-struvite and Mg(OH)2 are present in the final hydrated products. The compressive strength of MKPC at 3 d and 28d is 22.5% and 26.1% higher than that of control sample, the porosity of MKPC pastes decreases by 23.5% and 25.3% compared with control sample with 10 wt% of K-struvite at the age of 3d and 28d. K-struvite provides the nucleation site, which increase the quantity of hydration products as nucleating seeding. This work gives an innovative idea to partially replace MKPC by K-struvite, which provide theoretical reference for the practical application of MKPC.

Basic properties and mechanism of high activity phosphate-based slurry for dynamic water blocking-A feasibility research

The water inflow into a karst pipeline is characterized by great flow rate and fast flow speed, which makes it difficult to block. Phosphate cement has the characteristics of rapid setting, fast hardening, and good interface bonding, which have inherent advantages for plugging pipelines. However, under the condition of high water ratio, whether the performance of phosphate cement can still maintain the characteristics of rapid setting and fast hardening needs to be studied. In this paper, based on the characteristics of phosphate cement, the feasibility of using high activity phosphate slurry to block the water gushing in karst pipeline was studied. The basic properties of the slurry with different the molar ratio of the MgO to the KH2PO4, such as setting time, strength and viscosity were studied with the condition of high water-binder ratio. The hardened slurry was tested by X-ray diffraction, thermogravimetric Analysis and scanning electron microscopy analysis, and its microscopic mechanism was analyzed. The results show that under the condition of water-cement ratio 1.0, using light burned magnesia as raw material, the slurry can achieve quick setting and hardening, and it is found that the molar ratio of the MgO to the KH2PO4 has a great influence on setting time, strength and micro properties. The research showed that potassium magnesium phosphate cement is feasible to prepare dynamic water plugging material that use light burned MgO as raw material under high water-cement ratio.

Preparation and characterization of novel environmentally sustainable mortars based on magnesium potassium phosphate cement for additive manufacturing

<abstract> <p>The "Digital Transition" of the building sector and in particular the concrete 3D printing is profoundly changing building technologies and construction processes. However, the materials engineering is still a challenge for the research of even more effective and performing 3D printable concrete. In this context, we analysed magnesium potassium phosphate cement (MKPC) performance as an innovative cementitious material in terms of sustainability and possibility of its use in extrusion-based 3D concrete printing (3DPC). Starting from common formulations present in literature, we discussed the relationship between water to binder ratio and workability in two different quantities of retarders. Some mix compositions were also prepared by replacing sand with rubber aggregates or glass aggregates with the aim of creating lightweight aggregate-based mortars. In addition, the fly ash (FA), a widely material used (but that will not be available in the next few years), was replaced with silica fume (SF). We found that two formulations (samples 2 and 7) show rheological requirements and compressive strengths at 90 min of respectively about 2 MPa and 3 MPa, which are deemed to be suitable for 3D printing processes. Moreover, in sample 7, the use of the expanded recycled glass as aggregate opens new possibilities for reducing the carbon footprint of the process.</p> </abstract>

Temperature transformation of blended magnesium potassium phosphate cement binders

In this study, a multi-technique approach was utilised to determine the high temperature performance of magnesium potassium phosphate cement (MKPC) blended with fly ash (FA) or ground granulated blast furnace slag (GBFS) with respect to nuclear waste immobilisation applications. Conceptual fire conditions were employed (up to 1200 °C, 30 min) to simulate scenarios that could occur during interim storage, transportation or within a final geological disposal facility. After exposure up to 400 °C, the main crystalline phase, struvite-K (MgKPO4·6H2O), was dehydrated to poorly crystalline MgKPO4 (with corresponding volumetric and mass changes), with MgKPO4 recrystallisation achieved by 800 °C. XRD and SEM/EDX analysis revealed reaction occurred between the MgKPO4 and FA/GBFS components after exposure to 1000–1200 °C, with the formation of potassium aluminosilicate phases, leucite and kalsilite (KAlSi2O6 and KAlSiO4), commensurate with a reduced relative intensity (or complete elimination) of the dehydrated struvite-K phase, MgKPO4. This was further supported by solid-state NMR (27Al and 29Si MAS), where only residual features associated with the raw FA/GBFS components were observable at 1200 °C. The high temperature phase transformation of blended MKPC binders resulted in the development of a glass/ceramic matrix with all existing porosity infilled via sintering and the formation of a vitreous phase, whilst the physical integrity was retained (no cracking or spalling). This study demonstrates that, based on small-scaled specimens, blended MKPC binders should perform satisfactorily under fire performance parameters relevant to the operation of a geological disposal facility, up to at least 1200 °C.

Prospective usage of magnesium potassium phosphate cement combined with Bougainvillea alba derived biochar to reduce Pb bioavailability in soil and its uptake by Spinacia oleracea L

Combining biochar (BR) with other immobilizing amendments has additive effects on Pb immobilization and been recognized to be effective for the restoration of Pb polluted soils. However, the impacts of different proportions between BR and a highly efficient Pb immobilizing agent called “magnesium potassium phosphate cement (MC)” have never been earlier investigated. This work aimed to investigate the consequences of BR and MC alone and their mixtures of 25:75, 50:50, and 75:25 ratios on Pb bioavailability, Pb immobilization index (Pb−IMMi), and enzymatic activities in Pb polluted soil. Furthermore, amendments effects on Pb distribution in spinach, growth, antioxidant capacity, biochemical, and nutritional spectrum were also investigated. We found that MC alone performed well to immobilize Pb in soil and reducing its distribution in shoots, but was less efficient to improve soil enzymatic activities and plant attributes. Conversely, the application of BR alone stimulated soil enzymatic activities, plant growth, and quality but was less effective to immobilize Pb in soil and reducing shoot Pb concentrations. The combinations of BR and MC of various ratios showed variable results. Interestingly, the most promising outcomes were obtained with BR50%+MC50% treatment which resulted in enhanced Pb−IMMi (73%), activities of soil enzymes, plant growth and quality, and antioxidant capacity, compared to control. Likewise, significant reductions in Pb concentrations in shoots (85%), roots (78%), extractable Pb (73%) were also obtained with BR50%+MC50% treatment, compared to control. Such outcomes point towards a cost-effective approach for reducing Pb uptake by the plants via using MC and BR at a 50:50 ratio.

Enhancing the mechanical properties and cytocompatibility of magnesium potassium phosphate cement by incorporating oxygen-carboxymethyl chitosan.

Incorporating bioactive substances into synthetic bioceramic scaffolds is challenging. In this work, oxygen-carboxymethyl chitosan (O-CMC), a natural biopolymer that is nontoxic, biodegradable and biocompatible, was introduced into magnesium potassium phosphate cement (K-struvite) to enhance its mechanical properties and cytocompatibility. This study aimed to develop O-CMC/magnesium potassium phosphate composite bone cement (OMPC), thereby combining the optimum bioactivity of O-CMC with the extraordinary self-setting properties and mechanical intensity of the K-struvite. Our results indicated that O-CMC incorporation increased the compressive strength and setting time of K-struvite and decreased its porosity and pH value. Furthermore, OMPC scaffolds remarkably improved the proliferation, adhesion and osteogenesis related differentiation of MC3T3-E1 cells. Therefore, O-CMC introduced suitable physicochemical properties to K-struvite and enhanced its cytocompatibility for use in bone regeneration.

Experimental study on the effects of the fiber and nano-Fe2O3 on the properties of the magnesium potassium phosphate cement composites

In this study, a new cement-based composite is developed by the combined action of fiber and nano-Fe2O3 (NF) in magnesium potassium phosphate cement (MKPC) mortar. The performances of MKPC composite with fiber and NF are evaluated, including the workability, compressive strength, splitting tensile strength, flexural toughness and flexural ductility. The microscopic mechanism of MKPC with NF is revealed by using the Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The main variables of this study include fiber type, curing time, micro-steel fiber (MSF) volume rate and NF substitution rate, and the micro-steel fiber (MSF), cut hook (CH), milling hook (MH) and macro-polypropylene fiber (MPF) are selected as the reinforcing material. In comparison to other fibers, the MSF has the most significant positive effect on the mechanical properties of FNRMC. The compressive strength, splitting tensile strength, flexural toughness and flexural ductility of FNRMC evidently increase with increasing MSF volume rate, while the workability of FNRMC gradually decreases. The compressive and splitting tensile strengths of FNRMC have a trend of first increasing and then decreasing with increasing NF substitution rate from 0% to 4%.

Development and Evaluation of the Magnesium Potassium Phosphate Cement Based Refractory

In this work, the phosphate bonded refractory was developed using magnesium potassium phosphate cement. The Cement was prepared from the caustic calcined magnesium oxide with the addition of mono potassium phosphate. The characterization of the cement was done by XRD and SEM to examine the change in phase and morphology which occurs after the hydration of magnesium potassium phosphate cement which is in the struvite phase. To evaluate the physical, mechanical and thermal properties, refractory samples were casted and subsequently dried and fired at temperatures ranged from 1300 °C to 1500 °C. The effect of temperature on the bulk density, apparent porosity and crushing strength were analyzed. It was found that the properties of the chemically bonded refractory were better than the conventionally bonded calcium alumina cement refractory.

A study of the bond behavior of FRP bars in MPC seawater concrete

Using magnesium potassium phosphate cement (MPC) and fiber-reinforced polymer (FRP) bar to produce reinforced concrete can overcome the durability problems facing conventional steel reinforced PC concrete. In addition, FRP bar reinforced MPC concrete can also mitigate the CO2 emission issues caused by Portland cement (PC) production and the shortage of natural resources such as virgin aggregates and freshwater. This paper, therefore, is aimed at investigating the bond behavior of the FRP bars in MPC seawater concrete. The direct pullout tests were conducted with a steel bar, BFRP bar, and GFRP bar embedded into different concretes. The effects of reinforcing bars, type of concrete and mixing water on the bond behavior of FRP and steel bars were investigated and discussed. The results showed that the MPC concrete increases the bond strength of BFRP and GFRP bars by 51.06% and 24.42%, respectively, compared with that in PC concrete. Using seawater in MPC concrete can enhance the bond strength of GFRP bar by 13.75%. The damage interface of the FRP bar -MPC is more severe than that of PC with a complete rupture of the FRP ribs and peeling-off of the resin compared to that in steel reinforced MPC specimens. Moreover, the bond stress-slip models were developed to describe the bond behavior of MPC-FRP specimen, and the analytical results match well with the experimental data. In conclusion, the FRP bars showed better bond behavior in the MPC seawater concrete than that in the PC counterparts.

Influence of hybrid graphene oxide/carbon nanotubes on the mechanical properties and microstructure of magnesium potassium phosphate cement paste

This research reports the effect of hybrid graphene oxide (GO)/carbon nanotubes (CNTs) on the mechanical and microstructural properties of the magnesium potassium phosphate cement (MKPC) paste. The experimental results confirmed that the hybrid GO/CNTs exhibited better dispersion performance than the CNTs and GO individuals by improving the dispersion stability and reducing the diameters of dispersed nanomaterials, making the hybrid GO/CNTs more suitable for nano-modification of cement composites. Furthermore, the addition of GO/CNTs shortened the final setting time and reduced the fluidity of the MKPC paste. The compressive and flexural strength of the MKPC paste was improved by 13.77% and 17.50% respectively by the addition of 0.05% GO/CNTs (by weight of cement). The incorporation of the hybrid GO/CNTs also refined the pore size distribution and improved the crystallization of the hydration products. A higher content of hybrid GO/CNTs and the utilization of polycarboxylate superplasticizer further enhanced the mechanical properties of the MKPC paste. The X-ray diffraction and Fourier transform infrared spectrometer results confirmed the absence of new phases or any chemical bonding between the hybrid GO/CNTs and the pastes. It could be concluded that the hybrid GO/CNTs were relatively promising when compared with the GO or CNTs individuals, possessing great potential for modifying the MKPC paste.