CaCO3 Loading Research Articles

CaCO3 powder-mediated biomineralization of antigen nanosponges synergize with PD-1 blockade to potentiate anti-tumor immunity

Antigen self-assembly nanovaccines advance the minimalist design of therapeutic cancer vaccines, but the issue of inefficient cross-presentation has not yet been fully addressed. Herein, we report a unique approach by combining the concepts of “antigen multi-copy display” and “calcium carbonate (CaCO3) biomineralization” to increase cross-presentation. Based on this strategy, we successfully construct sub-100 nm biomineralized antigen nanosponges (BANSs) with high CaCO3 loading (38.13 wt%) and antigen density (61.87%). BANSs can be effectively uptaken by immature antigen-presenting cells (APCs) in the lymph node upon subcutaneous injection. Achieving efficient spatiotemporal coordination of antigen cross-presentation and immune effects, BANSs induce the production of CD4+ T helper cells and cytotoxic T lymphocytes, resulting in effective tumor growth inhibition. BANSs combined with anti-PD-1 antibodies synergistically enhance anti-tumor immunity and reverse the tumor immunosuppressive microenvironment. Overall, this CaCO3 powder-mediated biomineralization of antigen nanosponges offer a robust and safe strategy for cancer immunotherapy.

A WO3–TiO2 nanorod/CaCO3 photocatalyst with degradation-regeneration double sites for NO2-inhibited and durable photocatalytic NO

As a promising cleaner technology for nitric oxide degradation, photocatalysis has attracted extensive attention, while the main limitations of photocatalytic nitric oxide are that the toxic NO2 is produced easily and the photocatalytic durability was inferior due to the accumulation of photocatalytic products. In this paper, a WO3–TiO2 nanorod/CaCO3 (TCC) insulating heterojunction photocatalyst with degradation-regeneration double sites was prepared by simple grinding and calcining. The effects of CaCO3 loading on the morphology, microstructure and composition of TCC photocatalyst were investigated by SEM, TEM, XRD, FT-IR and XPS etc. Also, TCC exhibits NO2-inhibited and durable characteristics for NO degradation. DFT calculation, the detection of active radicals by EPR, capture test and the NO degradation pathway characterized by in-situ FT-IR spectra showed that the electron-rich region formed and the existence of regeneration sites are the main reasons for promoting the NO2-inhibited and durable NO degradation. Furthermore, the mechanism of NO2-inhibited and durable NO degradation by TCC was revealed. Finally, TCC superamphiphobic photocatalytic coating was prepared, which still exhibits similar NO2-inhibited and durable characteristics for NO degradation to TCC photocatalyst. It may provide new application value and development prospects in the field of photocatalytic NO.

Calcium Carbonate in Waste Flooring for Neutralization of Acid Rock Drainage.

Acid rock drainage (ARD) was successfully neutralized in this study using carpet tiles. Most polyolefin-based carpet tiles contain over 65% of finely ground calcium carbonate (CaCO3) powder by weight in the compound-blended and extruded backing structure; therefore, using them for neutralization is an innovative way to reuse a difficult-to-recycle complex and abundant product. The overall neutralization efficiency potential was calculated at 40% based on the density, purity, and surface images that display the domains of CaCO3 on the tiles. The carpet backing increased the mean of proton activity of AMD collected from a single acidic stream point within the Pinkerton Run tributary near Pittsburgh, PA from 3.3 to 6.1 over the span of four hours in batch-method experiments at CaCO3 loading levels of 0.1g/L and overall surface area exposure of 229 mm2/mL. Hot acidity levels decreased from 90 to less than 10mg CaCO3/L, and below detection limits after 20h of neutralization. The treated and neutralized AMD sample contained 80mg/L more calcium than the untreated, non-neutralized control, demonstrating the dissolution of CaCO3 from the carpet tile.

Lactic Acid Production from Sequential Inorganic Salt Pretreated Oil Palm Empty Fruit Bunch via Simultaneous Saccharification and Fermentation

Lactic acid is produced from inorganic salt pretreated oil palm empty fruit bunch (OPEFB) for the first time through simultaneous saccharification and fermentation (SSF). OPEFB is an agricultural waste that can be turned into lactic acid (LA), a highly desired chemical product. An inorganic salt (Na3PO4.12H2O-FeCl3) pretreatment precedes SSF with Bacillus coagulans DSM2314. The effect of solid loading, concentration CaCO3 and enzyme loading on LA generation is studied using design of experiments. The results show that solid loading and concentration CaCO3 affect LA yield. 50g/L biomass, 50g/L CaCO3 concentration, and 50 FPU/g cellulase enzyme yield maximal LA (46.66/L) and yield (0.93/g OPEFB). The model created to predict LA production was then validated.

Unified Therapeutic‐Prophylactic Vaccine Demonstrated with a Postoperative Filler Gel to Prevent Tumor Recurrence and Metastasis

AbstractAlthough surgical resection is currently the first choice of clinical treatment for most solid tumors, postoperative cancer recurrence and metastasis are the main causes of mortality. Herein, the authors aim to enable immunotherapy consistent with surgery. To this end, the term “therapeutic‐prophylactic vaccine (TPV)” is suggested, and a TPV‐gel is developed as a filler after resection of ≈90% tumor to eradicate residue tumor (therapeutic) and prevent recurrence and metastasis (prophylactic). The TPV‐gel is made of the matrix of blends of two poly(d,l‐lactide‐co‐glycolide)‐b‐poly(ethylene glycol)‐b‐poly(d,l‐lactide‐co‐glycolide) block copolymers and the bioactive substances of inorganic calcium salt and organic R837. The aqueous system of polymeric block blends undergoes a sol‐gel transition upon heating and thus leads to an injectable hydrogel filling the resection site; loading of CaCl2 and CaCO3 results in the release of calcium ions out of the TPV‐gel, which induces immunogenic cell death of the residual tumor cells; R837, an immune adjuvant, is dispersed in the TPV‐gel as microcrystal and can be released to awaken immune responses. The therapeutic and prophylactic efficacy of this TPV‐gel is confirmed in vitro and in vivo using a postoperative breast 4T1 mice model.

One-pot synthesis of Ca-based magnetic hydrochar derived from consecutive hydrothermal and pyrolysis processing of bamboo for high-performance scavenging of Pb(Ⅱ) and tetracycline from water

Ca-based magnetic bamboo-derived hydrochar described as Ca-MBHC was synthesized by one-pot pyrolysis, and was applied to remediation of lead (Pb) and tetracycline (TC) polluted water. Characterizations not only attested the loading of CaCO3 and Fe0 onto the hydrochar, but also demonstrated the magnetism of Ca-MBHC. Adsorption kinetic experiments showed that the Ca-MBHC could eliminate Pb(II) and TC during a wide range of pH, and appeared rapid uptake equilibrium within 240 and 60 min for Pb(II) and TC, severally. Adsorption isotherm experiments showed that the Ca-MBHC possessed highest adsorption of 475.58 mg/g concerning Pb(II), and heterogeneous uptake of 142.44 mg/g for TC. Furthermore, the Ca-MBHC could achieve Pb(II) binding owing to complexation, reduction, ion exchange and electrostatic attraction, whereas the TC uptake might be related to π-π stacking reciprocities, pore filling and hydrogen bonding. Overall, the Ca-MBHC could be viewed as an excellent adsorbent for scavenging Pb(II) and tetracycline from water.

Thermo‐mechanical, rheological and morphology properties of polypropylene composites: Residual CaCO3 as a sustainable by‐product

AbstractThis research looked into the possibility of using residual calcium carbonate (CaCO3) as a by‐product of the cane sugar production process combined with polypropylene (PP) to replace commercial CaCO3. Using a co‐rotating twin‐screw extruder, the CaCO3/PP composites were made in the following ratios: 10:90, 20:80, 30:70, 40:60, and 50:50, with the addition of maleic anhydride polypropylene at 5 wt% of CaCO3. In terms of mechanical properties, thermal properties, rheological properties, and morphology, the effect of the residual CaCO3 filler reinforced in PP matrix was compared to commercial CaCO3/PP composites. The findings showed that residual CaCO3 from the sugar production process can replace the use of industrial CaCO3 mixing in plastic and can add value to the residual CaCO3. The residual CaCO3/PP composites had better tensile modulus, flexural strength, flexural modulus, impact resistance, and thermal stability than commercial CaCO3/PP composites, according to the findings. The composites' tensile modulus, flexural modulus, hardness, thermal stability, and rheological properties improved as the CaCO3 loading increased.

Evaluation of vital features of PVA–CaCO3 nanocomposite films for biodegradable packaging applications

Environmental pollution due to non-biodegradable packaging materials is a menace. Hence, with a societal concern, an attempt was made through this paper to fabricate and evaluate pore-free nanocomposite films with PVA as the matrix with various wt% CaCO3 as a nanofiller through various physical parameters for alternate biodegradable packaging. The films are fabricated by a solution casting method. Optical, morphological, structural and dielectric studies were made on the films. Improvements in mechanical and thermal properties were observed in the films because of CaCO3 loading. Biodegradability of the composite films was immensely thus replacing the present non-biodegradable packaging materials. Increase in biodegradability with time and wt% of CaCO3 was highlighted. The low dielectric constant combined with the biodegradable nature of the films might prove useful in microelectronic packaging and thin/foldable/wearable optoelectronics. The investigated properties of the films establish multifunctionality and merit applications in the designing of packaging materials.

Nature-inspired CaCO3 loading TiO2 composites for efficient and durable photocatalytic mineralization of gaseous toluene

The accumulation of intermediates or final products on TiO2 during photocatalytic volatile organic compounds (VOCs) degradation is typically neglected, despite the fact that it could result in the block of active sites and the deactivation of photocatalysts. Inspired from the natural formation of stalactite (CaCO3 + H2O + CO2 ↔ Ca(HCO3)2), we fabricated CaCO3 loading TiO2 composites (CCT21) to realize the spontaneously transfer of accumulated final products (CO2 and H2O). Efficient and durable performance for gaseous toluene removal has been demonstrated and the cost of photocatalyst is greatly reduced by the comparison of specific activity. The introduction of CaCO3 induces the interaction between TiO2 and CaCO3 to stimulate abundant activated electrons for the improvement on the adsorption and activation of reactants and the transformation of photogenerated carriers, and most importantly, facilitates the transfer of final products to release active sites and thus suppress the deactivation of TiO2. Furthermore, we develop a facile method to immobilize CCT21 powder on flexible support, which greatly reduces the loss of photocatalysts and correspondingly enables the practical application of TiO2-based products. Therefore, this work presents a novel nature-inspired strategy to address the challenge of deactivation, and advances the development of photocatalytic technology for environmental remediation.

Influence of modified carbonate calcium nanoparticles on the mechanical properties of carbon fiber/epoxy composites

Multiscale composites have been investigated by the addition of silanized carbonate calcium (CaCO3) as a secondary reinforcement into the matrix of carbon fiber/epoxy composites. The chemical modification of the CaCO3 nanoparticles was confirmed by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Mechanical properties of the specimens were investigated by means of tensile, flexural, and compressive measurements to study the effect of treated CaCO3 loading (0.5, 1, 3 and 5 wt.%) on their mechanical behavior. Experimental results showed that the tensile, flexural and compressive strengths of the specimen filled with 3 wt.% treated CaCO3 composite enhanced by 14%, 36%, and 30% respectively, compared with those of neat one. The highest improvements in the mechanical moduli were observed in the multiscale composite filled with 5 wt.% treated CaCO3. Also, the fracture surface of the specimens was further analyzed in detail.

Preparation and Characterization of Hybrid Composite Film Based on Synthetic and Natural Materials

Low density polyethylene / tapioca starch (LDPE/TS) blends have respectable biodegradation properties and poor mechanical and thermal properties compared to neat LDPE film. The focal target of this study is to investigate the effect of calcium carbonate (CaCO3) loading on mechanical, thermal, and biodegradation properties of LDPE/TS film. LDPE/TS/CaCO3 blend films were prepared using film blown processing. The results indicated that the maximum loading of CaCO3 which feasible to be incorporated into (45:20) LDPE/TS blend is 10% without exertions during film processing. CaCO3 has remarkable effect on mechanical properties of LDPE/TS films in both machine direction (MD) and cross direction (CD). Water absorption capacities of the films were reduced after the addition of CaCO3. Differential scanning analysis shows that more amorphous regions were generated in the blend structure after the addition of CaCO3 into the blend. Scanning Electron Microscope (SEM) analysis indicated a significant distribution of starch and CaCO3 particle in LDPE matrix, wherever the size of starch particles seems to be bigger than the size of CaCO3 particle.

Preparation and characterization of red seaweed/calcium carbonate composite films

This study aims to evaluate the influence of inorganic filler on the properties of seaweed-based film. Seaweed composite films were prepared from raw red seaweed (Kappaphycus alvarezii) in the presence of glycerol with the incorporation of calcium carbonate (CaCO3). Solution casting technique was used to form films and dried at 40 ˚C in the ventilation oven for 24 hours. The effects of different CaCO3 concentrations [0.5%, 1.0%, 1.5%, 2.0% (wt. %)] on the physical, mechanical, and thermal properties were determined. Molecular interaction between the functional groups of red seaweed and CaCO3was examined through Fourier transform infrared spectroscopy (FTIR). The obtained result demonstrated that the addition of CaCO3 improved the neat seaweed film properties in terms of tensile strength, hydrophobicity, thermal properties and reduced the problem of brittleness encountered in seaweed-based film. However, excessive loading of CaCO3 had led to weaker film properties. Raw red seaweed and CaCO3 has shown compatibility through the analyses of FTIR, thermal, and mechanical of the composite films.

Combined Fe2O3 and CaCO3 Additives To Enhance the Immobilization of Pb in Cathode Ray Tube Funnel Glass

Cathode ray tube (CRT) funnel glass has posed an increasing threat to the environment due to its rapid replacement by new technology in recent years. In this study, a well-control thermal scheme was applied for synthesizing a specific crystalline phase, PbFe12O19, for Pb immobilization when reusing CRT funnel glass as raw materials for the ceramics industry. The Fourier transform infrared spectroscopy results show that introduction of CaCO3 facilitated the breakage of strongly connected bonds between O–Si–O and Pb–O, which were firmly linked in the glass network. The X-ray diffraction results demonstrate that 30 wt % CaCO3 loading effectively facilitated the transformation of Pb in CRT funnel glass to the stable-phase PbFe12O19. A higher sintering temperature increased Pb transformation efficiency while a longer dwelling time only showed a slight increase in PbFe12O19 formation. The prolonged toxic characteristic leaching procedure results show a substantial improvement in the acid resistance (approximate...

Thermal, Morphological and Physic-Mechanical Properties of Natural Rubber - CaCO3 Composites Using Jatropha Oil as Softener.

The urgency of green technology in rubber compounding has become a critical issue recently. In this research, the effect of using renewable resources in rubber compounding has been studied. Commercial Calcium Carbonate, Silica and Jatropha Oil were used in natural rubber composite. The research was designed by varying the types of commercial filler namely CaCO3 (47-51) phr, silica (47-51) phr and Jatropha Oil (4-6) phr in natural rubber composites (SIR-20). The formulas were intentionally designed for rubber tips vulcanizates. The samples were characterized by the determination of physic-mechanical, thermal (TGA) and morphological (SEM) properties. From the measured results, there is no significant effect on the tensile strength, specific gravity, and hardness on the loading of commercial CaCO3 and Silica in natural rubber composites using Jatropha Oil. However, a slight difference in elongation at break and abrasion resistance could be detected. Compared to the commercial rubber tips, the rubber tips produced in this research have higher tensile strength, elongation at break and abrasion resistance. Due to the usage of commercial CaCO3 and Silica, the SEM micrographs show rough surface because of the agglomeration. The thermogram shows clearly the compositional analysis of the rubber tips vulcanizates consist of Jatropha Oil and natural rubber, CaCO3, ash and other filler residues such as Silica.

CO2-looping in pyrolysis of horse manure using CaCO3

This study laid a great emphasis on the mechanistic understanding of CO2 in pyrolysis of horse manure to establish a virtuous cycle for carbon in the thermo-chemical process. To this end, CaCO3 was used as a possible candidate for the CO2 resource to impart synergistic environmental benefits. This study also proved the genuine roles of CO2 in pyrolysis of horse manure. CO2 could be a driving force to shift carbon distribution from pyrolytic oil to pyrolytic gas (i.e., the enhanced generation of CO), which provides a new means for modifying the composition of syngas as well as pyrolytic oil. Shifting carbon distribution from pyrolytic oil to pyrolytic gas could be explained through two genuine roles of CO2 in pyrolysis of horse manure. For instance, CO2 led to the enhanced thermal cracking of volatile matters evolved from the thermal degradation and the direct reaction between CO2 and volatile matters to form CO, which lead to the enhanced generation of syngas and the reduction of tar formation. These identified genuine roles of CO2 were initiated temperatures higher than 500 °C, when temperature could be decreased down to 450 °C in the presence of CaCO3 due to the catalytic effects arising from CaCO3. Thus, all experimental findings will be directly applicable to gasification since pyrolysis is an intermediate step in the gasification process. Moreover, the high content of CaO in biochar can be reused in the diverse environmental applications. However, the optimal conditions, especially for optimal CaCO3 loading, should be established through further study on the subject.

Chitosan reinforced with modified CaCO3 nanoparticles to enhance thermal, hydrophobicity properties and removal of cu(II) and cd(II) ions

The role of nanoparticles (NPs) in the enhancement of thermal, wettability and adsorption properties of chitosan (CS) was inspired by loading of CaCO3 modified with diacid (DA) based on L- phenyl aniline (2–8 wt%) within the CS by ultrasound agitation. The diameter of CaCO3-DA into the CS extended from 40 to 70 nm. A thermal test on the CS/CaCO3-DA nanocomposite (NC) 2 wt% revealed that T 5 (temperature with 5% weight loss) was increased up to 312 °C, which is twice the value of the pure polymer. The wettability property of the CS/CaCO3-DA NCs was transformed from hydrophilicity to hydrophobicity as the CaCO3-DA NPs concentration was increased. It is due to decrease of the accessibility of the CS polar groups to water. The CS/CaCO3-DA NC 5 wt% was selected as the adsorbent for uptake of metal ions from the wastewater. It showed maximum adsorption capacity of 21.74 and 29.41 mg.g−1 for Cu(II) and Cd(II), respectively. These are attributed to strong complexation reaction between the metal ions and functional groups in the obtained NC.

Effect of Ingredient Loading on Vulcanization Characteristics of a Natural Rubber Compound

Rheometric properties of rubber compounds are usually monitored with time during the course of vulcanization at constant temperature. The measured vulcanization characteristics of rubber compound are used for quality control and evaluation of raw materials and product formulations. With the high number of ingredients used in typical formulations, it is important to identify ingredients which significantly affect the vulcanization characteristics of a rubber compound. This study reports the vulcanization characteristics of a natural rubber compound at 60 °C as function of ingredient loading. Rubber sheets are compounded according to a 212-8 fractional factorial design of experiment, where ingredients are treated as factors varied at low and high loadings. Vulcanization curves, which are time plots of elastic torque S’, viscous torque S”, and tan δ = S”/S’, are measured for each rubber sheet using a moving die rheometer. The following responses are then determined from the vulcanization curves for data analysis: minimum elastic torque ML, maximum elastic torque MH, torque difference ∆S = MH – ML, scorch time ts1, cure time t’90, cure rate index CRI = 100/ (t’90 – ts1), S” and tan δ values at ML and MH. Analysis of variance (ANOVA) shows used oil to be the main ingredient affecting vulcanization of the natural rubber compound (ML, MH, ∆S, ts1, S” at ML and MH), followed by sulfur (MH, ∆S, CRI), calcium carbonate CaCO3 (S” at ML, tan δ at MH) and diphenylguanidine DPG (ts1). High loading of used oil lowers the elastic and viscous response of the rubber compound, while increases the time for scorch. Increased loading of sulfur significantly enhances the elastic torque and cure rate of the compound. High loading of CaCO3 improves the viscous response, while DPG significantly shortens the scorch time of the rubber compound.

Changing Breathability of Polyethylene Composite Films with Different Porous Structures Depending on Stretching Processes

ABSTRACTThe aim of this work is to investigate the effects of different stretching processes on breathability performance of linear low‐density polyethylene (LLDPE)/coated calcium carbonate (CaCO3) composite films under the same conditions. Coated calcium carbonates and powdered LLDPE were physically mixed and dried in a high shear mixer, and polymer compounds containing 45 and 55 wt% coated calcium carbonate were generated using a twin screw extruder. Cast films were produced and then they were stretched 3.5 times in machine direction at 25°C by using stenter and interdigitation stretching methods. It was revealed that not only the CaCO3 type and loading amount but also the stretching type has an enormous effect on breathability performance. In addition, the quality of porosity, that is, the amount of interconnecting pores, was determined to play an important role in breathability. And, the interdigitation stretching process offers the potential for a better breathability at reduced processing costs.

Investigation of internal concentration polarization reduction in forward osmosis membrane using nano-CaCO3 particles as sacrificial component

Calcium carbonate (CaCO3) nanoparticles were used as sacrificial additives to fabricate PSf substrate membranes and based on which thin film composite (TFC) membranes were prepared using m-Phenylenediamine (MPD) and 1, 3, 5-trimesoylchloride (TMC) as the monomers. Then CaCO3 nanoparticles dispersed in PSf matrix were effectively etched with hydrochloric acid to increase the substrate porosity. The effect of CaCO3 loading (ranging from 0 to 10.0wt%) was systematically investigated. The results showed that the substrate membranes fabricated with CaCO3 incorporation exhibited higher porosity and smaller structural parameter, which is advantageous for improving water permeability and reducing mass transfer resistance. As for forward osmosis (FO) performance, the TFC membranes fabricated using modified substrates exhibited much higher water flux than the control TFC membrane prepared by substrate without CaCO3 incorporation in both AL-FS and AL-DS mode when using DI water as the feed and 2M NaCl as draw solution. The optimized TFC21 membrane also had better performance than other commercial TFC membranes in simulated seawater desalination. Moreover, the reduced membrane structural parameter indicated that the internal concentration polarization (ICP) could be mitigated via the etching method. This study provides a low cost and feasible way to reduce the ICP in FO membranes.

Electrospun chitosan/poly(vinyl alcohol) reinforced with CaCO3 nanoparticles with enhanced mechanical properties and biocompatibility for cartilage tissue engineering

Abstract The role of CaCO3 nanoparticles as a reinforcing agent in increasing the mechanical properties of electrospun chitosan/poly(vinyl alcohol) (PVA) is inspired by the incorporation of CaCO3 inside a chitin network in nature. The loading concentration of CaCO3 nanoparticles varied from 1 to 5 wt%, and the diameter of fibers ranges from 71.5 ± 23.4 nm to 140.7 ± 15.1 nm with an increased loading of CaCO3. A tensile test on 4 wt% CaCO3-reinforced fibers revealed a Young’s modulus up to 912.5 ± 60.6 MPa from 15.7 ± 3 MPa, which is almost sixty times the value of fibers without CaCO3. The biocompatibilities of the CaCO3-loaded fibers were also tested in a 14-day simulated body fluid (SBF) incubation to induce the formation of apatite minerals and in a 14-day cell proliferation assay with ATDC5 cells. The chitosan/PVA–CaCO3 (4 wt%) was found to provide the most suitable environment for cell growth in comparison with chitosan/PVA and chitosan/PVA–apatite. The CaCO3-reinforced chitosan/PVA has potential to be a promising alternative as an artificial cartilage.