Raw Clay Minerals Research Articles

Low-cost and high-safety montmorillonite-based solid electrolyte for lithium metal batteries

Composite solid-state electrolyte have good interfacial compatibility and mechanical properties, but their safety (such as easy to catch fire) and economic cost are still problems. In present work, an composite solid-state electrolyte was prepared by inserting poly(vinylidene fluoride)-based polymer electrolyte matrix into the interlayer of a low cost clay mineral-montmorillonite. The composite electrolyte exhibited remarkable characteristics, including excellent flame retardancy, high room temperature ionic conductivity of 2.28 × 10−4 S cm−1, wide electrochemical stability window of 4.8 V, high lithium-ion transference number of 0.57 and good mechanical strength of 12.58 MPa. Furthermore, LiFePO4-based solid-state battery, utilizing this composite solid-state electrolyte, exhibited stable cycling with discharge specific capacity of 130 mAh g−1 for over 100 cycles at a rate of 0.5C at room temperature. This successful performance demonstrated the potential of utilizing low-cost and environmentally friendly raw clay mineral materials in high energy density solid-state battery applications.

Impact of treatment temperature of metakaolin on strength and sulfate resistance of concrete

Calcined clay, a widely studied supplementary cementitious material, has shown positive impacts on concrete's microstructural properties, strength development, and durability. The variation in raw clay mineral concentration across different locations influences the optimal calcination temperature needed to activate its pozzolanic reactivity. This investigation focuses on studying the effects of calcination temperature on the characterization and pozzolanic reactivity of Nigerian Kaolinite clay. The clay was calcined at temperatures ranging from 600˚C to 900˚C for 2 hours. Characterization involved X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and Scanning Electron Microscope (SEM) analyses. Blended mixtures, incorporating 10%, 20%, 30%, and 40% metakaolin as cement replacement, were assessed for workability, strength, and durability properties at 7, 14, 28, and 56 days to determine the clay's pozzolanic reactivity. XRF categorized the metakaolin as a class N pozzolan, while XRD indicated that 800˚C for 2 hours was necessary for complete dihydroxylation. Compressive, tensile, and sulfate resistance tests confirmed that treating the clay at 800˚C for 2 hours optimized its performance. The mix with 10% metakaolin outperformed the control by 6.4%, 14.7%, and 14.1% in compressive strength at 14th, 28th, and 56th days, respectively. While the best performance was at 10% replacement, levels up to 30% also demonstrated satisfactory results compared to the control, showing potential for achieving desired strengths. Linear regression models were also developed to establish the relationship between compressive and split tensile strengths across curing periods. The resulting equations demonstrate excellent predictive performance with correlation coefficients ranging from 0.928 to 0.991.

Clay-based 1D-2D halloysite&g-C3N4 nanostructured meat floss for photocatalytic hydrogen evolution

Graphitic carbon nitride (g-C3N4) has drawn extensive attention with some features including visible-light response as non-metallic semiconductor, low cost in raw material and green pollution-free for environment, but suffers from some issues such as fast charge carriers’ recombination, easy aggregation, etc. In this work, the 1D-2D HNTs&g–C3N4–X binary materials similar to meat floss pattern in a series of halloysite loading amounts are designed via a facile electrostatic self-assembly strategy with debris g-C3N4 after cell pulverizing treatment and HNTs that outwardly modified by cetyltrimethylammonium bromide (CTAB) as the building blocks. The halloysite-mediated satellite-core material displays a photocatalytic of H2 evolution performance with the highest evolution rate of 137.0 μmol g−1 h−1 in visible light condition with no co-catalysts, and is ∼3.4 times that of bulk g-C3N4, mainly benefiting from the reduced nanometer size of debris g-C3N4 and enhanced interface dispersion ability by HNTs, resulting in ameliorative separation efficiency of photogenerated charge carriers. This research conclusively provides the new perspective towards the performance enhancement of water splitting of g-C3N4 in raw clay mineral modification mode and broadens the applications of mineral-based composite in the renewable energy utilization field.

A technological approach based on engineered nanoclay composites for cesium and iodine retention.

The development of effective and environmentally friendly methods for separating hazardous radionuclides from waste poses a significant technological challenge. 137Cs and 131I are among the most important radionuclides discharged into the environment by nuclear power plants. One of the best ways to eliminate them involves adsorption on clay minerals. In this regard, studies have demonstrated that organofunctionalized clay minerals are effective adsorbents. Thus, this study investigates the capability of organofunctionalized synthetic design clay minerals to jointly eliminate cesium and iodine. The adsorbents studied are a range of organofunctionalized clay minerals with alkylammonium cations of different alkyl chain lengths (2, 3 and 18) and some physical mixtures of raw clay minerals and octadecylammonium compounds. Organofunctionalized synthetic swelling highly charged micas are effective adsorbents for the simultaneous adsorption of cesium and iodine. In addition, the optimal system is a mixture of Na-M4 with octadecylammonium (50% w/w).

Optimisation of the reaction conditions for biodiesel from Parkia biglobosa oil via transesterification with heterogeneous clay base catalyst

Transesterification reaction of Parkia biglobosa oil (0.61% w/w free fatty acid and 191.65 (mgKOH/g) saponification value) with methanol to biodiesel using heterogeneous bi-functional Clay-Na2CO3 catalyst was carried out. The bi-functional heterogeneous clay base catalyst was prepared using incipient impregnation method. Following grinding and sieving, the raw clay mineral was soaked in 9 ml Na2CO3 overnight. It was subsequently dried at 120 °C for 12 h and finally calcined at 450 °C for 4 h. The properties of the prepared catalyst was then studied using FTIR, SEM, UV Spectrum, EDS and XRD. The optimum conditions for the transesterification reaction include 12:1 molar ratio of methanol to oil, 2 wt% concentrations of catalyst, reaction temperature of 60 °C and 1.5 h of reaction. The maximum yield obtained under conditions was 94.7%. With the exception of the oxidative stability wahich was higher than the recommended standard by American and European Union, all the other properties of the biodiesel were within the limits of American Standard (ASTM D6751), European Standard (EN 14,241) and Ghana Standard Authority. The catalyst could be cheap with superior activity for which reason it could be a potential candidate for producing biodiesel from new non-edible Parkia biglobosa oil. The application of the biodiesel produced from Parkia biglobosa will help improve the lubrication properties of diesel fuel blend which will subsequently help reduce engine wear in diesel engines since biodiesel is a good lubricant.

Highly efficient aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over halloysite nanotubes-templated nitrogen-doped carbon supported bimetallic AuPd catalyst

Aerobic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) is an important way to produce bioplastic monomer. Herein, halloysite nanotubes (HNT)-templated layered porous hollow rod-shaped nitrogen-doped carbon supported bimetallic AuPd catalysts (AumPdn/HRNxC) with different nitrogen contents and bimetallic nanoparticles size were employed for the highly efficient aerobic oxidation of HMF to FDCA in sodium carbonate aqueous solution. Catalytic experimental results uncovered the possible reaction pathway, and the kinetics study further confirmed the oxidation of intermediate FFCA to FDCA was the rate-controlled step. Benefiting from the synergy between nitrogen-doped carbon support and bimetallic nanoparticles, the Au3Pd1/HRN5C catalyst obtained the highest HMF conversion of 100% and FDCA yield of 99.9% under the optimal reaction conditions. In-situ FT-IR study revealed the adsorption configuration of HMF, and the ESR test proved that the active substance was superoxide radical. Furthermore, the catalyst showed good stability and reusability. This work provides an efficient, economical and environmentally friendly raw clay mineral derived heterogeneous catalyst for the large-scale production of FDCA from HMF.

Paper of RILEM TC 282-CCL: mineralogical characterization methods for clay resources intended for use as supplementary cementitious material

To respond to the rapid introduction and development of calcined clays as supplementary cementitious material (SCM), the toolbox of characterization methods for cementitious materials requires extension to raw clay characterization. Borrowing concepts and methods developed in the field of clay mineralogy, this paper outlines the merits and limits of widely accessible characterization techniques for raw clays intended for use as SCM, when calcined. The paper focuses mainly on the identification and quantification of the raw clay mineral components, as these characteristics have important implications for further material processing and performance. General notes are provided on clay sampling and pre-treatment as well as bulk chemical analysis. The main techniques considered are X-ray diffraction, thermal analysis and infrared spectroscopy. Their application on raw clays is introduced, highlighting clay-specific aspects of sample preparation, data acquisition, and processing. Guidelines and interpretation tables are provided to aid in the analysis of the acquired data, while limitations and potential interferences are identified. Options for remote prospection by infrared spectroscopy are included as well. To illustrate the type of information to be gained and the complementarity of the techniques, two representative raw clays are fully characterised. This paper aims to highlight that mineralogical characterization is a feasible and often necessary step in the study and assessment of raw clays that can deliver a wealth of informative data if carried out appropriately.

Mica-based triboelectric nanogenerators for energy harvesting

Mica, an abundant raw clay mineral, has negatively charged silicate layers owing to the replacement of Si atoms with Al atoms; hence, it easily loses electrons during the friction contact with other materials. Mica is reported as the most positive inorganic non-metal triboelectric material. However, the triboelectric performance characteristics of mica and its influencing factors have not been sufficiently studied. Herein, a triboelectric nanogenerator (TENG) was fabricated using a raw mica layer and a polytetrafluoroethylene film as the positive and negative friction materials, respectively. The effects of the mica layer thickness, air-bubble defect in mica, applied force, and working frequency on the TENG performance were investigated. Mainly owing to the excellent positive triboelectric property and extremely flat and smooth surface of mica, the mica-based TENG achieved the maximum output power density of 62.82 mW/m2. A multi-layer sandwich mica-based TENG generated −147 V under the force of 1 N. Moreover, the mica layers attached to a shoe sole could harvest mechanical energy when walking on a plastic floor, thereby directly lighting four LEDs. This study reveals that mica exhibits excellent triboelectric performance and is a promising positive friction layer candidate for environmentally friendly TENGs.

Effects of Clay Mineral Composition on the Dynamic Properties and Fabric of Artificial Marine Clay

Marine clays are easily affected by different mineral composition in cyclic load-based geological hazards. Therefore, based on analyzing the mineral composition of natural marine clay, it is the key to predict the dynamic properties of natural materials under cyclic loading by using quantitated artificial marine clay. In this study, the marine clay found in the South China Sea deltas was investigated. Based on the results of geological conditions and mineral composition analyses, raw non-clay minerals (such as quartz, albite) and clay minerals (such as Na-montmorillonite and kaolinite) were used to produce artificial marine clay, the dynamic properties of which were studied from the impact of mineral composition. Dynamic triaxial laboratory testing for artificial marine clay comprising various clay minerals was performed under identical test conditions. The artificial marine clay with high montmorillonite content exhibited slower development of strain, more sluggish growth in pore water pressure, more rounded hysteresis curves, greater stiffness, and more prolonged viscous energy growth than the clay with low montmorillonite content. In addition, the flocculated fabric of the artificial marine clay with high montmorillonite content demonstrated sufficient pore space changes, more uniform pore distribution, and larger specific surface area than the dispersed fabric of the clay with low montmorillonite content. The factors arising from the influence of montmorillonite may lead to microstructural and fabric changes, hinder the development of pore water, and increase intergranular contact stiffness as well as delay the cyclic strain amplitude at the breakpoint of viscous energy dissipation. In general, the results presented in this study confirm that clay minerals, especially montmorillonite, have significant influence on the dynamic properties of large strain.

The traces of Mining in Lubsko (western Poland) - proposal of the geotouristic path

Lubsko is a city in the Lubuskie province (western Poland) with a population around 15 000. The use of raw clay minerals in this region has its beginning in the Middle Ages. Through the years the production has changed to the centralised mining industry. The end of this branch has begun in the late 1980s due to the political changes in Poland. Nowadays, the signs of this significant history of the city are ruined or in bad conditions. The reason for organising geotouristic path is to protect the geoheritage of this region, mainly old open-pits and the infrastructure. Proposed stops will teach about the mining heritage in Lubsko, the geology of the glacial region, the processing of raw clay minerals and various usages of this material. Moreover, connecting both didactic and recreational use may give the chance to integrate touristic sites in the city. The development of such a path may attract tourists from Poland and Germany, which may result in an improvement of the financial situation of Lubsko. Considering the possible benefits and obstacles the SWOT analysis is presented in the article.

Synthesis and characterization of clay nanocomposites based on starch

ABSTRACTIn this work, the synthesis of starch-clay nanocomposites was carried out. For this purpose, natural starch was extracted from rice grains and it was characterized by structural and spectrophotometric techniques. Afterwards, it was used as the polymer matrix for the synthesis of nanocomposites crosslinked with different agents: glycerol, citric acid (CA) and sodium trimetaphosphate (STMP). As a reinforcement phase, a natural Mexican clay from the Montmorillonite-type (Mt), was employed, which was modified with a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), in order to exchange cations, present in the interlaminar spaces of the raw clay mineral with those of the cationic surfactant; thus, changing its nature from hydrophilic to hydrophobic. Characterization, of both natural and organo-modified clays, was carried out by means of scanning electron microscopy (SEM), to determine the change in morphology between these two minerals; X-ray diffraction analysis (XRD), to obtain the crystalline structure of the organo-modified clay and that of the raw clay mineral (Mt). Also, the Fourier transform infrared spectroscopy (FTIR) was employed to determine materials spectra, and their thermal stability was evaluated by means of the thermogravimetric analysis (TGA). On the other hand, the synthesis of these nanocomposites was performed using different crosslinking agents, glycerol, CA or STMP, in order to identify the effect of them into the final properties of these materials.

Tuning down the environmental interests of organoclays for emerging pollutants: Pharmaceuticals in presence of electrolytes

The impact of electrolytes on the adsorption of emerging pollutants: pharmaceuticals onto layered materials: a raw clay mineral and its nonionic and cationic organoclay derivatives was studied. The selected pharmaceuticals: amoxicillin, norfloxacin, sulfamethoxazole, metoprolol, carbamazepine, and trimethoprim show different electric charges: zwitterionic, anionic, cationic and neutral and hydrophobic character (different LogP). Without any salts, the set of complementary data obtained by UV and infrared spectroscopies, X-ray diffraction points out the importance of the electric charge which represents a key parameter in both the spontaneity and feasibility of the adsorption. In contrast, the hydrophobicity of the analytes plays a minor role but determines the magnitude of the adsorbed amount of pharmaceuticals onto organoclays. With a dual hydrophilic and hydrophobic behavior, nonionic organoclay appears to be the most polyvalent material for the removal of the pharmaceuticals. In the presence of electrolytes (NaCl at a concentration of 1 × 10−2 mol L−1), both nonionic and cationic organoclays show a decrease of their efficiencies, whereas the adsorption is particularly enhanced for Na–Mt except for the cationic species (trimethoprim and metoprolol). Thus, in realistic experimental conditions close to those of natural effluents, raw clay mineral appears as the most appropriate sorbent for the studied pharmaceuticals while it raises the question of the usefulness of organoclays in water remediation strategy.

Amine grafting of acid-activated bentonite for carbon dioxide capture

A low-cost bentonite (ZBent) and acid-activated derived samples have been employed as clay adsorbents to assess their performance for pure CO2 adsorption in a thermogravemetric system. The raw bentonite reached a CO2 uptake of only 6.2 mg/g ads due to its low specific surface area and pore volume. After acid modification, an increase in its specific surface area and pore volume was observed, due to the leaching of octahedral cations and the generation of an amorphous silica phase. However, the degradation of the clay structure only improved slightly the adsorption of CO2. In a next step, raw and acid-treated clay minerals were functionalized with two different amine species (aminopropyl-trimethoxysilane; AP, and diethylene-triamine-trimethoxysilane; DT) by grafting. Unlike the case of DT species, the incorporation of AP moieties favored the chemical interaction between the amines species and the CO2 molecules in all cases. Functionalization with AP molecules increased the adsorption capacity of CO2 up to 29.2 mg/g ads at 30 °C for ZBent-24 h-AP, the material obtained after longer acid treatment time and functionalized with AP. AP-functionalized samples also had good stability and reusability during eight cyclic adsorption/desorption tests.

Competitive Association of Antibiotics with a Clay Mineral and Organoclay Derivatives as a Control of Their Lifetimes in the Environment.

A Na-smectite clay mineral (Na-Mt) was exchanged with two concentrations of benzyldimethyltetradecyl ammonium chloride cationic surfactant up to one time the cation exchange capacity. Nonionic organoclay was prepared with polyoxyethylene (20) oleyl ether (Brij-O20) nonionic surfactant at one concentration. The resulting organoclays displayed lateral layer organization of the surfactants within their interlayer space.. The adsorption properties of these organoclays and the starting raw clay mineral were evaluated for three extensively used antibiotic pharmaceutical products: the amoxicillin (AMX), the sulfamethoxazole (SMX), and the trimethoprim (TRI), recognized as recalcitrant compounds to conventional water treatments and to display a complex behavior for different pH and temperature experimental conditions. Besides showing short half-life time with possible degradation by UV radiation, these antibiotics associated with mineral phases cause serious environmental issues of which the toxic effect can be exacerbated in the presence of other chemical compounds. From the set of data obtained by complementary techniques: UV and Fourier transform infrared spectroscopy, high-performance liquid chromatography coupled with mass spectrometry, and X-ray diffraction, it appears that the nonionic organoclay shows its versatility for the adsorption of individual molecules as well as a pool of antibiotics. The mixing of the three antibiotics showing different electric charged species (cations, anions, and zwitterions) mimics the natural context drives to a deep modification of the adsorption behavior onto the different materials that can act as possible carrier mineral phases in aquatic environment. These competition effects can be measured through the significant decrease of the KF Freundlich constants for AMX in the presence of other molecules (or electrolytes), whereas TRI and SMX, by their possible association, create a synergistic effect that favors their adsorption on the whole layered materials.

Chitosan-smectite composite on the urea adsorption–desorption study for slow-release fertilizer application

PurposeThe purpose of this study is to prepare composite of chitosan-modified smectite clays consisting of montmorillonite and saponite clay minerals and their urea adsorption–desorption study. Prepared materials were designed for slow-release fertilizer application.Design/methodology/approachPreparation of the composites was conducted by a simple intercalation of chitosan solution and clay suspension followed by hydrogel beads formation. Physicochemical characterization of materials was performed by X-ray diffraction, gas sorption analysis by using Brunauer–Emmett–Teller surface areas and pore volume, water absorbency and Fourier transform-infrared. Urea adsorption and desorption studies of prepared materials were conducted by using batch method, and the adsorbed and desorbed urea content was analyzed by using high-performance liquid chromatography method.FindingsThe results revealed that the composites have higher absorptivity and lower absorptivity toward urea from and into water solution compared to raw clay minerals. Adsorption capacity and slow desorption rate of urea from the composites suggested the potential application of the composites as slow urea-releasing agent.Originality/valueThere are many papers that study the formation of chitosan-clay composites, but the study on the urea adsorption–desorption properties based on chitosan-smectite minerals have not been reported. Intensive study related to physicochemical properties and its related kinetics study is an important basic finding for further applications.

Halloysite-derived mesoporous g-C3N4 nanotubes for improved visible-light photocatalytic hydrogen evolution

Abstract Hydrogen evolution via visible-light photocatalytic water splitting is an ideal solution to the worldwide energy and environmental crisis, while the key challenge is to develop efficient and cheap photocatalysts. Here, mesoporous graphitic carbon nitride (g-C3N4) nanotubes were synthesized using modified halloysite as template via a facial vapor deposition method. The halloysite-derived mesoporous g-C3N4 nanotubes exhibited an excellent photocatalytic hydrogen evolution efficiency of 633 μmol g−1 h−1 under visible light irradiation, which was 14.3 times that of bulk g-C3N4. The improvement of photocatalytic activity mainly benefits from the enlarged specific surface area and the reduced recombination rate of photoinduced electron-hole pairs of the mesoporous g-C3N4 nanotubes. The strategy established here may be valuable for synthesizing efficient g-C3N4 photocatalysts with other tailor nanostructures utilizing diverse raw clay minerals.

Alterações estruturais de Cr-beidelita tratada até 1350 °C em atmosferas de oxigênio ou nitrogênio

Abstract Beidellite clay mineral after intercalation of OH-Cr(III) species were thermally analyzed up to 1350 °C in oxygen and nitrogen atmospheres. OH-Cr-beidellite can be used as a pillared clay precursor for catalysis or as adsorbent applications. However, in this paper beidellite enriched in chromium were analyzed at different thermal treatments up to high temperature for evaluating structural changes for possible future ceramic applications. The structural changes were followed by thermal analysis and X-ray diffraction. The thermal treatment of OH-Cr-beidellite in oxygen and nitrogen atmospheres developed different mineralogical phases up to 1050 °C, but at higher temperatures, the same phases were developed in both atmosphere treatments. Eskolaite phase (Cr2O3) appeared in the sample after heating at 400 °C in oxygen atmosphere, whereas grimaldite (CrO-OH) in nitrogen atmosphere, maintaining the starting phases. At 1000 °C the raw clay minerals disappeared, as it is knew. At 1050 °C in nitrogen atmosphere, grimaldite was absent and eskolaite appeared. At 1350 °C in the samples calcined in both atmospheres, quartz, cristobalite and mullite as the main phases and in lower contents aluminum oxide and aluminum-chromium oxide [(Al,Cr)2O3] were present.

Investigation of biomass gasification using indonesian clay as catalyst

Gasification is one of the technologies to process biomass as a renewable alternative energy source. Steam biomass gasification using various clays derived from Indonesia was carried out with laboratory scale fluidized bed reactor to evaluate the activities of clay as catalysts. At the same time to elucidated the relationship between material bed characteristics and gasification process activity. Tar capturing ability was compared for activated clay, silica sand and clay minerals derived from Indonesia by using a laboratory scale fluidized bed reactor. Even raw clay minerals were found to reduce heavy tar and water-soluble species emissions and increased carbonaceous materials deposited on the bed materials compared to activated clay. Activity of some Indonesian clay revealed high performance on the biomass gasification due to the amount of acid center.

Development of palygorskite-SO42 −/ZnAl2O4 composites as a novel solid acid catalyst for the esterification of acetic acid with n-butanol

A novel series of palygorskite-SO42−/ZnAl2O4 (PAL-S/Z) composites were simply synthesized by loading ZnAl2O4 on raw clay minerals of palygorskite (PAL) for acid catalysis of acetic acid and n-butanol. The prepared PAL-S/Z composites were characterized by means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TG). The experimental results indicated that the support of PAL played a significant role in the good dispersion of ZnAl2O4 active components and consequently improved the catalytic performance of PAL-S/Z composites. Compared with SO42−/ZnAl2O4 (S/Z), PAL-S/Z composites showed the higher catalytic activities with above 98% conversion of acetic acid in the esterification of acetic acid with n-butanol. Meanwhile, the structures and the catalytic performance of PAL-S/Z composites were significantly affected by PAL/ZnAl2O4 ratio. The optimal PAL/ZnAl2O4 ratio was 1:1 and PAL-S/Z (1:1) exhibited 98.7% conversion of acetic acid under the optimum synthesis conditions and reaction conditions. Particularly, PAL-S/Z (1:1) showed a better reusability, which could remain above 85% conversion of acetic acid even after being used for seven times in the esterification of acetic acid with n-butanol.

Structural, electrokinetic and surface properties of activated palygorskite for environmental application

Unlike smectite, the surface characteristics of palygorskite remain underexplored for its potential application in environmental remediation. In this study, palygorskite from Western Australia was activated through thermal (300°C for 4h), acid (4M HCl for 2h at 70°C) and acid-thermal (acid treatment followed by heating at 300°C for 4h) treatments, and the structural and physico-chemical characteristics were examined against the raw clay mineral. The influence of activation was systematically investigated using X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, N2 adsorption-desorption measurements and solid state 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. The XRD patterns indicated preservation of the crystalline structure of palygorskite following all the treatments. These findings were supported by the Al (IV) and Al (VI) coordination peaks (chemical shift ~55 and 2.9ppm, respectively) which were unaltered in the 27Al MAS NMR spectra of the samples. The acid-thermal activated palygorskite exhibited the highest specific surface area (152.7m2g−1) and pore volume (0.2137cm3g−1) which respectively were 3-fold and 69% greater than the raw palygorskite. The potentiometric titration analyses highlighted the possible role of Al derivatives towards development of the surface charge of the activated palygorskites. Electrokinetic studies described the stability of the activated products (zeta potential values ranging from -5mV to -32mV) at different electrolyte (NaNO3) concentrations. Combined acid-thermal activated palygorskite displayed a stronger specific adsorption of multivalent cations, and held a direct relevance to environmental remediation. Findings of this study will assist in the development of palygorskite-based adsorbents for heavy metal contaminants remediation.