KAOLIN

Kaolinite Al 2 Si 2 O 5 (OH) 4 is an abundant and inexpensive geomaterial regarded as one of the most common clay minerals in the earth's crust and the most widespread phase among the other kaolin polymorphs (halloysite, dickite and nacrite). Structurally, it is a hydrous aluminum phyllosilicate member belonging to the dioctahedral 1:1 kaolin mineral group. The particle size of the pseudohexagonal kaolinite platelets is normally <2μm (if compared to a human red blood cell of a typical diameter 6.2-8.2μm or to a virus particle of about 50nm diameter). The kaolinite platelets, either stacked together with a common booklet-like shape in a highly ordered structure (well crystallized) or disordered structure (poorly crystallized), consist of layers considered as a strong dipole of hydrophobic siloxane surface dominated by negative charges, and the other hydrophilic aluminol surface carries positive charges. Kaolinite has been used in many pharmaceutical applications as excipient or active ingredient, because it exhibits excellent physical, chemical and surface physicochemical properties. In addition to their classical pharmaceutical uses, kaolinite and its derivatives have been recently considered as a promising material in many biomedical innovation areas such as drug, protein and gene delivery based on the high interaction capacities with organic and biochemical molecules, bioadhesion and cellular uptake. Pharmaceutical kaolin grades are considerably demanded for usage as excipient in formulations of solid and semi-solid dosage forms. The most important functionalities of kaolin used as excipient are reported as diluent, binder, disintegrant, pelletizing and granulating, amorphizing, particle film coating, emulsifying and suspending agent. Because of its uninjured bioactivity, kaolinite has been also used as active agent for treatment of some common diseases. It can be topically administered as hemostatic agent, dermatological protector, anti-inflammatory agent and in pelotherapy, or orally as gastrointestinal protector, and antibacterial, antiviral, detoxification or antidiarrheal agent. With these premises, the future of kaolinite in health-care uses is strongly interesting, especially in the development of pharmaceutical and cosmetic industries. In biomedicinal investigations, it can be considered as a promising natural geomaterial for designing new derivatives that can contribute in the trials of discovering new therapeutic systems and treatment pathways of global challenge diseases such as cancer, viruses, antibiotic resistant bacteria, alzheimer, chronic skeletomuscular and geriatric diseases.

The increasing daily use of cosmetic and personal care ingredients (CPCIs) requires improved understanding of the fate and impacts of CPCIs in environmental systems. Effects of CPCIs on colloidal properties of various geocolloids such as iron oxides (goethite, haematite), clay minerals (kaolinite, bentonite) and soil clays (kaolinitic-, illitic- and lateritic soil clays) were studied by tracking time-resolved changes in zeta potential (ζ) and observing suspended particle density. Two polymers representing anionic CPCIs, i.e., polyacrylate crosspolymer-11 (PC11) and cationic CPCIs, i.e., polyDADMAC (PD) show contrast effects on ζ and colloidal properties of the selected materials. While PC11 tended to associate with Fe oxides, PD can be adsorbed by clay minerals and soil clays. The neutralization due to the sorption of either PC11 or PD onto opposite-charge sign surface sites can lower the net surface charge of the materials, thereby enhancing electrostatic attraction, stimulating particle size growth, and eventually intensifying co-aggregation. The observed colloidal properties of iron oxides, clay minerals and soil clays under the presence of PC11 and PD may reflect what are happening in many aquatic environments where CPCIs co-exist with various mineral colloids. Therein, CPCIs likely delay the transport of the opposite-charge sign colloids, while they increase the dispersibility and transportability of the same-charge sign colloids. This implies that intensifying presence of a given CPCI could have selective effects on colloid systems. As a whole, CPCIs can change the fate and the final destination of mineral colloids and themselves; therefore, their effects and relevant treatment techniques need to be included into the future agenda.

Uncontrolled hemorrhage from trauma or surgery can lead to death. In this study, chitosan/kaolin (CSK) and chitosan/montmorillonite (CSMMT) composites were prepared from chitosan (CS), kaolin (K), and montmorillonite (MMT) as raw materials to control bleeding. The physiochemical properties and surface morphology of CSK and CSMMT composites were analyzed by Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potentials, and X-ray fluorescence (XRF). The hemostatic mechanism was measured in vitro by activated partial thromboplastin time (APTT), prothrombin time (PT), in vitro clotting time, erythrocyte aggregation, and thromboelastogram (TEG). The hemostasis ability was further verified by using tail amputation and arteriovenous injury models in rats. The biocompatibility of CSK and CSMMT was evaluated by in vitro hemolysis, cytotoxicity assays, as well as acute toxicity test and skin irritation tests. The results show that CSK and CSMMT are promising composite materials with excellent biocompatibility and hemostatic properties that can effectively control bleeding.

The Expert Panel for Cosmetic Safety (Panel) assessed the safety of 8 naturally-sourced clay ingredients, of which 6 were previously reviewed, as used in cosmetic formulations. All of these ingredients are reported to function in cosmetics as absorbents and bulking agents; other cosmetic functions are also reported. The Panel reviewed all relevant data and concluded that Kaolin is safe in cosmetics in the present practices of use and concentration described in this safety assessment. The remaining 7 naturally-sourced clay ingredients are safe in cosmetics in the present practices of use and concentration, with the exception that the available data are insufficient to make a determination that these ingredients are safe in products that may be incidentally inhaled.

This study investigates the radiological characteristics and potential health implications of Balengou kaolin, a clay widely mined in Western Cameroon, used as a building material and distributed nationwide for geophagy and cosmetic purposes. Fifteen kaolin samples and ten surrounding control soil samples were collected, prepared, and analysed using a NaI(Tl) γ-ray spectrometer to determine 226 Ra, 232 Th, and 40 K activity concentrations and establish an environmental baseline for earthen building materials. Complementary α-spectrometric analyses quantified uranium and thorium isotopes on six selected samples, following radiochemical separation and electrodeposition. The mean activity concentrations in Bq.kg -1 were 118 ± 62 for 40 K, 47 ± 4 for 226 Ra, and 145 ± 9 for 232 Th, yielding mean gamma absorbed dose rates of 211.48 and 113.84 nGy h -1 , and annual effective doses of 1.04 and 0.13 mSv.y -1 for indoor and outdoor, respectively. A voluntary survey (N = 201), conducted in major urban centres where Balengou kaolin is consumed, provided data on the ingestion and cosmetic use habits of kaolin, which served as input for PHITS Monte Carlo dose calculations. Organ and effective doses from ingestion and dermal application, estimated using PHITS and ICRP mesh-type reference computational phantoms, showed the highest doses in the colon and stomach, reaching 1.2 mSv.y -1 for frequent female consumers, whereas external doses from cosmetic use were negligible (<1 μSv.y -1 ). This integrated approach provides a comprehensive radiological assessment of Balengou kaolin across environmental, construction, and human-use contexts and establishes a reference dataset for future studies and public awareness initiatives.

Dental effluents often contain persistent cationic antiseptics, such as chlorhexidine gluconate (CHG) and cetylpyridinium chloride (CPC). These substances raise environmental concerns due to their widespread clinical use, antimicrobial persistence, and poor biodegradability. This study investigates the synthesis and evaluation of kaolin-gallic acid functionalized gamma-chitosan/alginate (γCS-AG/KA-GA) composite beads for the adsorption of CHG and CPC from aqueous solutions and real dental wastewater. The composite beads were prepared by ionic cross-linking of gamma-irradiated chitosan and alginate in a CaCl 2 bath. Kaolin and gallic acid were incorporated to enhance both structural stability and adsorption functionality. Comprehensive characterization techniques, including high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD), confirmed the successful formation of a porous hybrid composite with an increased surface area of 68.9 m 2 ·g -1 . Batch adsorption experiments showed rapid uptake of both antiseptics within 60 min, reaching equilibrium at 180 min. The adsorption behavior was well described by the Langmuir isotherm ( R 2 > 0.98) and the pseudo-second-order kinetic model ( R 2 ≈ 0.99), resulting in maximum adsorption capacities of 82.7 mg·g -1 for CHG and 75.3 mg·g -1 for CPC. When applied to authentic dental wastewater collected from the BTU Dental Clinic, the γCS-AG/KA-GA beads achieved a removal efficiency of 65 ± 3%. This slight reduction in performance compared to synthetic systems was attributed to ionic competition and matrix fouling. Overall, these results demonstrate that γCS-AG/KA-GA composite beads provide a promising, sustainable, and material-based approach to reducing antiseptic contamination in dental effluents and promoting greener dental wastewater management strategies.

Uncontrolled hemorrhage and wound healing difficulties are significant challenges in medical care. Wounds that fail to close within a limited time frame are often associated with continuous hemorrhage, hard-to-treat infections, and chronic conditions. Sepia melanin that contains eumelanin and is extracted from the ink of cuttlefish Sepia officinalis exists as agglomerates in the natural state, and it can be disassembled using kaolinite (D-SM-Kaolin) to accelerate hemostasis and wound healing. D-SM-Kaolin fabrication using Sepia melanin cross-linked with kaolinite through dissolving, disassembling, and sedimentation, and different alkaline solvents controlled within a certain range. Hemostatic evaluation in vitro and in vivo, D-SM-Kaolin exhibited accelerated hemostatic effects, and thereinto, the blood loss takes 5 times less than contrast items. The hemostatic mechanism involves kaolinite's intrinsic clotting cascade and facilitating blood constituents concentration at the hemorrhage site. In a normal wound model, D-SM-Kaolin also exhibited an accelerated wound healing, and more collagen formation combined with tissue cell infiltration was observed. The wound healing mechanism was attributed to the D-SM-Kaolin absorbs the excess wound exudate and accelerates the wound closure at the wound sites, besides SM's intrinsic adhesion effect and kaolin's intrinsic clotting cascade characteristic. These findings suggest that SM agglomeration could be eliminated using kaolinite, and thus is more beneficial to the field of hemostasis and wound healing.

Kaolinite stands out as a promising natural geomaterial for developing new therapeutic systems aimed at addressing global health challenges, such as multidrug-resistant infections. In this study, we report on the formulation and biological activity of a therapeutic mixture composed of white micronized kaolinite (KAO) and Ziziphora essential oil (ZEO), intended for topical application on infected wounds. GC-MS analysis revealed that the primary component of ZEO is pulegone, constituting 72.98% of the oil. ZEO demonstrated good bioactivity against bacterial and fungal strains (MIC 1.25-5 mg/mL). Additionally, ZEO at a concentration of 0.0156% (0.156 mg/mL) was found to significantly stimulate collagen synthesis. The antimicrobial activity of the tested KAO-ZEO mixture formulation (30% KAO/0.25% ZEO in an excipient base) showed the highest effectiveness against Candida spp. (MIC 0.08-25 mg/mL) and Gram-positive bacteria (MIC 0.16-25 mg/mL), with lower activity against Gram-negative bacteria (MIC 25-50 mg/mL). Moreover, the KAO-ZEO mixture was nontoxic (cell viability near 100%) to human skin fibroblasts according to the ISO 10993-5 standard and promoted collagen synthesis by skin cells. This is the first documented formulation combining KAO and ZEO, demonstrating significant antimicrobial properties along with the ability to stimulate collagen production in fibroblasts. These properties highlight KAO-ZEO as a promising novel treatment, which may synergize with current care standards and improve wound healing outcomes.

The adsorption of trihalomethanes (THMs) from drinking water was investigated in the current study through comparison studies of kaolinite and ZnO@kaolinite nanocomposites. The clay structural network's successful immobilization on the zincite hexagonal structure of ZnO nanoparticles' lattice layers was verified by the SEM/EDX analysis. Under the optimum conditions, the maximum removal of THMs was achieved by kaolinite and ZnO@kaolinite nanocomposites after 60 min. The adsorption performance of the ZnO@kaolinite nanocomposites was greater than that of kaolinite because the former had a larger surface area than the latter. The Freundlich isotherm model best matched the adsorption experimental data, which also reveals the existence of multilayer adsorption on a diverse surface with the greatest correlation ( R 2 = 0.956 and 0.954, respectively) for both nanoadsorbents using the pseudo-first-order (PFO), pseudo-second-order (PSO), mixed 1, 2-order (MFSO), and intraparticle diffusion (IPD) models. The mechanism by which THMs in drinking water adsorb onto nanoadsorbents was examined. This revealed that both intraparticle and film diffusion were involved in the adsorption process. Kaolinite and ZnO@kaolinite nanocomposites can be used in water treatment to remove THMs due to their great recyclable and reusable properties, even after six cycles.

Skin wound management in veterinary medicine requires therapies able to control inflammation, limit microbial burden, and support tissue repair. This study evaluated the anti-inflammatory, wound-healing, and immunomodulatory effects of four novel topical formulations combining synthetic anti-inflammatory drugs, antibiotics, and plant extracts in rat experimental models. Burn injury was induced in male Wistar rats for wound-healing assessment, while kaolin- and dextran-induced paw edema models were used to assess anti-inflammatory activity. The tested formulations were meloxicam, dexamethasone, and levofloxacin; thyme extract with meloxicam and dexamethasone; burdock extract with dexamethasone and levofloxacin; and thyme extract combined with burdock extract. Wound evolution was monitored macroscopically, edema was quantified by plethysmometry, and selected inflammatory mediators were measured by immunoassay. In the burn model, the thyme-containing formulation with meloxicam and dexamethasone, and the thyme-burdock formulation, achieved complete wound closure by the end of follow-up, whereas the reference product did not. In the acute inflammation models, all innovative formulations significantly reduced edema at the main early time points compared with the negative control and outperformed the reference product. The thyme-burdock formulation also showed the most favorable immunomodulatory profile, including normalization of interleukin-10 and marked reduction in interleukin-1 beta in both models. These results support the potential of multi-component topical formulations, particularly plant extract-based combinations, as promising candidates for veterinary wound care.

Industrial wastewater frequently contains a huge of pollutants, such as heavy metals, dyes, and organic compounds, leading to considerable environmental discharge. Methylene Blue (MB), a cationic dye extensively utilized in the textile and pharmaceutical sectors, presents significant hazards to aquatic environments and human health. Exposure to MB may result in negative effects, including dermal irritation, stomach discomfort, and possible long-term ecological consequences. This research investigates the elimination of MB from synthetic industrial wastewater utilizing a geopolymer derived from Partially De-aluminated Metakaolin (PDK) by using adsorption technique it is a simple, low-cost, and effective method for removing a variety of pollutants. The geopolymeric materials were analysed using XRF, XRD, FTIR, SEM, EDX, and BET to confirm its structure then used for MB removal. The specific surface area of the geopolymer was determined to be 9.3 m 2 /g and a pore volume of 0.024 m 3 /g. Its kinetics and isotherms were investigated in the MB dye adsorption experiments. The adsorption was influenced by dose, initial dye concentration, pH, and contact time. According to the results, the maximum adsorption capacity (8 mg/g) was attained at 60 mg/L MB, 60 min of contact time, and pH 7-12 for one hour. The experimental data indicated that Freundlich isotherm model was the best-fit model to describe the sorption of MB on the synthesised geopolymer with higher determination coefficients R 2 of 0.996. Value of n greater than unity indicates a favourable adsorption taking place. This indicated that the adsorption occurs under a multilayer and heterogeneous surface for MB. The adsorption kinetics of MB onto GP was investigated using pseudo first order, and pseudo second order models as shown in, using the experimental data at various initial concentrations. The calculated parameters values obtained from the application of three models are tabulated. By comparing R 2 for each applied model and the compatibility between the estimated and observed q e values, the most favourable model may be identified. The pseudo 2 nd order R 2 value are greater than other models.

This study aims to develop a composite hydrogel consisting of nano silver (Ag) and graphene oxide (GO) for use as a skin wound dressing. We prepared nanosilver/graphene oxide composite hydrogels by incorporating nanosilver and graphene oxide into kaolin-reinforced, gelatin-based hydrogels. Tests were conducted on the hydrogel's water vapor permeability, mechanical properties, infrared warming performance and bacteriostatic properties under infrared light. The results indicated that kaolin enhanced the water vapor permeability and mechanical properties of the gelatin-based hydrogels. Moreover, the maximum fracture stress and strain of the hydrogel were elevated to 51.16 kPa and 1152.78% by GO, respectively. Furthermore, the modified Ag/GO hydrogels exhibited superior photothermal conversion and infrared bacteriostatic properties. This research offers valuable insights for the clinical repair of wounds and the design of new skin wound dressings, making these materials promising for such applications.

To assess the physical properties and topographical aspect of dental enamel's surface microhardness (KHN), surface roughness (Ra), and color parameters CIELAB (∆E ab *), CIEDE 2000 (∆E 00 ), and whiteness index for dentistry (∆WI D ) after toothbrushing with experimental toothpaste formulations with the following mineral clay types: kaolin, Sparclay SGY, and Tersil CGY used as abrasive component. Scanning electron microscopy (SEM) was performed for topographical analyses purposes. A total of 96 bovine incisors were used in the experiment. They were divided into eight experimental groups (n = 12), namely: NC-negative control (no treatment), CT12-Colgate Total 12®, CMP-Colgate® Máxima Proteção Anticáries, K-kaolin experimental toothpaste, SGY-Sparclay SGY experimental toothpaste; CGY-Tersil CGY experimental toothpaste, SD-SiO 2 experimental toothpaste, and CC-CaCO 3 experimental toothpaste. All samples were subjected to mechanical brushing protocol with 5000 cycles and kept in artificial saliva with daily exchanges. KHN was analyzed through the mixed linear model for repeated measures over time. Ra was analyzed through nonparametric Kruskal Wallis and Dunn tests to compare the groups. Paired Wilcoxon test was run to compare experimental times. ∆WI D , ∆E ab *, and ∆E 00 were analyzed through Kruskal Wallis and Dunn tests. All analyses were performed in R* software, at 5% significance level. EXP_SGY recorded higher KHN than EXP_SiO 2 and EXP_CaCO 3 , whereas EXP_K showed increased Ra in comparison to CMP (p = 0.0229). ∆E ab and ∆E 00 were significantly higher in the CT12, EXP_SiO 2 , and EXP_CaCO 3 groups than in the NC and EXP_K (p < 0.0001). There were no significant changes in ∆WI D (p = 0.0852). According to SEM results, toothbrushing with experimental toothpastes added with mineral clay types did not have significant impact on enamel's polishing and smoothness. CLINICAL RELEVANCE: Mineral clays have a broad application in the cosmetic industry, and recently, they have been used in the formulation of vegan toothpaste.

Oily skin, characterized by excessive sebum production, can lead to acne and have psychosocial impacts due to changes in appearance. Recent research has shown interest in treatments for oil control, with kaolin and bentonite emerging as promising options. Despite their potential, comprehensive studies on these ingredients are still in the nascent stages. This study aimed to assess the efficacy of a clay mask (La Roche-Posay Effaclar Sebo-Controlling Mask) in reducing skin oiliness and acne, and its safety for use. In this study, 75 adults with oily or combination skin were enrolled and provided with a clay mask for twice-weekly use over 4 weeks. Clinical assessments, using instruments like Sebumeter, Vapometer, and Corneometer, were conducted at baseline, and after 1, 2, and 4 weeks, evaluating acne lesions, skin irritation, sebum content, and skin hydration. Participant self-assessment questionnaires were also utilized for subjective evaluation. Statistical analyses were performed accordingly. The study revealed significant improvements in acne-related outcomes, sebum content, skin evenness, stratum corneum water content, and transepidermal water loss following the application of the clay mask. Pore area and porphyrin area showed no significant changes. Tolerance assessment showed reduced dryness and irritation, with self-assessment indicating high product acceptability and perceived oil control effectiveness. This study demonstrated the clay mask's efficacy in managing acne and oily skin, improving hydration and texture. Significant improvements in skin parameters and high product safety were observed, supporting its suitability.

Plant diseases induced by various phytopathogens pose a significant threat to contemporary agricultural systems around the world. In modern agriculture, the use of pesticides is still a valuable and effective method to control plant diseases. However, agrochemicals are becoming less popular because of the accretion of toxic compounds perilous and potentially hazardous to humans and the environment. Taking into consideration these aspects, the present study was conducted to explore the biocontrol potential of an endophytic Streptomyces sp. SP5 bioformulations against Fusarium wilt. Three bioformulations were prepared using cell biomass and different carriers, i.e., B1 (talc-kaolin), B2 (MgSO 4 /glycerol/Na-alginate/talc/Ca-lignosulfonate), and B3 (calcium carbonate/CMC/talc). Apart from antagonistic action against Fusarium wilt, the influence of bioformulations on plant growth and systemic resistance was investigated by analyzing morphological parameters (root length, shoot length, root weight, shoot weight), biochemical parameters (photosynthetic pigments, non-enzymatic antioxidants), and induction of antioxidative enzymes, e.g., catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and superoxide dismutase (SOD), in S. lycopersicum and C. annum seedlings. The results revealed that Streptomyces bioformulations effectively controlled Fusarium wilt in S. lycopersicum and C. annum (82.6-83.4% and 81.8-100%, respectively). Besides reducing disease prevalence, bioformulations significantly increased all the morphological parameters and increased the activity of antioxidative enzymes, i.e., CAT, APX, GPX, and SOD, in plants. The current findings display that bioformulations can be utilized as environment-friendly biocontrol agents against Fusarium wilt and also as plant growth promoters.