Natural Diatomite Research Articles

Bacillus Subtilis HU58 Immobilized in Micropores of Diatomite for Using in Self-healing Concrete

Recent studies reveal that using bacteria to mix into concrete material promote generating specific precipitated product. Such product allows improving physio-mechanical properties of concrete materials at both early and later age. This experimental study deals with the use of Bacillus subtilis HU58 and natural diatomite Lam Dong as controlled release agent to formulate bacterial concrete. We investigated self-healing effect during long period of curing time up to 24 months. Given in the result of material analysis, there is an increasing crystallinity of precipitated calcite by bacteria. At a smaller scale in bacteria modified mortar (prismatic samples 40x40x160mm), both compressive and flexural strengths increase in comparison with those of normal sample, 57 → 61MPa (in compression) and 9 → 11MPa (in flexion). At greater scale in bacterial concrete (cube samples 150x150x150mm), compressive strengths are higher (about 18%) than obtained results of normal concrete sample at age of 2 months. For the reason of better control of process of precipitation, Bacillus subtilis HU58 and nutrient were first immobilized in diatomite Lam Dong, before introducing in cement matrix. We examined self-healing capacity of crack opening that were artificially prepared (1-1.8mm by width) after early setting of cement mortar. Results of the water permeability test, developed in laboratory presented the evidence of remediating crack and fissure due to bacteria.

Synthesis and characterization of antimicrobial nanosilver/diatomite nanocomposites and its water treatment application

Nanotechnology for water disinfection application gains increasing attention. Diatomite is one kind of safe natural material, which has been widely used as absorbent, filtration agents, mineral fillers, especially in water treatment industry. Nanosilver/diatomite nanocomposites were developed in this publication with a facile, effective in-situ reduction method. The as-prepared nanosilver/diatomite nanocomposites demonstrated amazing antibacterial properties to gram-positive and gram-negative bacteria. The corresponding property has been characterized by UV–vis absorbance, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX) and X-ray Photoelectron Spectroscopy (XPS). Moreover, the detailed bacteria killing experiments further displayed that 0.5g of the nanosilver diatomite could kill >99.999% of E. Coli within half an hour time. And the silver leaching test demonstrated that the concentrations of silver in the filtered water under varies pH environment were below the limit for silver level of WHO standard. Considering the low price of natural diatomite, it is believed that the nanosilver/diatomite nanocomposites have potential application in water purification industry due to its excellent antimicrobial property.

Preparation of Poly-hydroxy-aluminum Pillared Diatomite and Characteristics of Cu2+, Zn2+ Adsorption on the Pillar in Aqueous Solutions

As an alternative solution to the limitations in adsorption properties of natural diatomite caused by its physicochemical structure defects and modification effects to diatomite using conventional physical/chemical methods, the diatomite was pillared using poly-hydroxy-aluminum to improve its adsorption properties. The change in physicochemical characteristics of the diatomite before and after pillaring were analyzed by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD). The difference in surface properties of diatomite and its adsorption characteristics of Cu2+, Zn2+ before and after pillaring were analyzed at the same time. The obtained results showed that the optimal conditions for diatomite pillaring were 2.2 of the [OH-]/[Al3+] molar ratio, 1.8 mol·L-1 of potassium chloride, 10 mmol·g-1 of the Al/diatomite ratio, 60℃ of the pillaring temperature, 24 h of the pillaring time, 200℃ of the aging temperature, and 0.5 h of the aging time. After pillaring, the poly-hydroxy-aluminum was successfully exchanged into the diatom shell, forming available pillars, which increased channel spacing, expanded adsorption reaction interface, increased the number of microporous surface hydroxy groups and enhanced the microporous surface activity. The Cu2+, Zn2+ adsorption data obtained both before and after pillaring well fitted the Langmuir isotherm model and the pseudo-second-order kinetics model. After pillaring, the adsorption capacity of Cu2+, Zn2+ onto diatomite reached 7.491, 11.312 mg·g-1, with an increasing percentage of 32.9%, 33.3% respectively, the diatomite adsorption capacity got great improvement.

Airborne toluene degradation by using manganese oxide supported on a modified natural diatomite

The catalytic combustion of toluene over manganese oxide supported on natural diatomite has been investigated in the paper. The catalyst was prepared by the wet impregnation method and characterized by using the Brunauer Emmett Teller, field emission scanning electron microscopy, X-ray diffraction, X-ray fluorescence and temperature-programmed reduction analysis. The higher activity of the catalyst supported on diatomite for toluene oxidation was obtained at 12 wt% Mn loading. It was able to convert 90 % of toluene (T 90) at 380 °C. The results indicated that the selectivity towards CO2 was almost 100 % and no intermediates, such as CO or other hydrocarbons, were detected.

Physicochemical characterization of a diatomaceous upon an acid treatment: a focus on surface properties by inverse gas chromatography

Natural diatomite from Sig/Algeria was treated with 0.5, 1.0, 3.0 and 5.0M nitric acid solutions for 2h under reflux at 333K in order to improve its performance as support of catalyst. The purified silica powders obtained from frustules can also be used to reinforce composites. The solids obtained were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy, thermal analyses, and nitrogen adsorption–desorption at 77K. Treatment of diatomite earth with nitric acid reduced mineral impurities, such as Fe2O3 and alkali metal oxides (CaO, MgO), eliminated carbonates and increased SiO2 ratio from 88% to 98%. The SEM micrographs showed the original geometry of the pores to be preserved. The surface properties were also evaluated using inverse gas chromatography at infinite dilution (IGC-ID) and finite concentration (IGC-FC). The interest here was to establish whether the technique is sufficiently sensitive to detect variations in the surface properties of the diatomite due to this chemical treatment. The IGC analysis permitted to reach several surface energy components with organic probes. Between them, the distribution function of the adsorption energy sites obtained with the isopropanol probe revealed a silica structure after the 5M nitric acid treatment.

Visible light photocatalysis of a textile dye over ZnO nanostructures covered on natural diatomite

In the present study, ZnO nanostructures were ultrasonically synthesized and immobilized on the surface of diatomite and used for visible light photocatalysis of Acid Red 88 (AR88) in the aqueous phase. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were employed for characterization of the samples. The process was optimized via response surface methodology (RSM) on the basis of central composite design (CCD). Based on numerical optimization, for the maximized color removal of 96% the initial dye concentration, the catalyst dosage, the reaction time, and the initial pH were 13 mg/L, 1.5 g/L, 85 min, and 4, respectively. The initial pH produced the largest effect, while the adsorbent dosage represented the lowest individual effect on the photocatalysis of AR88. The reusability test showed a 20% reduction in decolorization efficiency (%) within four consecutive experimental runs. Overall, ZnO-diatomite nanocomposite can be applied as an efficient photocatalyst for the visible light photocatalysis of target organic dyes.

Engineering of three dimensional (3-D) diatom@TiO2@MnO2 composites with enhanced supercapacitor performance

This work demonstrates a new and simple approach for fabrication a complex three-dimensional (3-D) composite for supercapacitor based on hollow diatom silica structures combined with interconnected coatings of TiO2 nanospheres and MnO2 mesoporous nanosheets (diatomite@TiO2@MnO2). The coating process is based on hydrolysis and metathetic reaction of TiF4 precursor followed by the reaction with KMnO4, which allows the coating of internal and external surface of diatom hollow structure with TiO2 and MnO2 layers. It was demonstrated that the introduction of anatase TiO2 layer on the 3-D diatomite@TiO2@MnO2 electrodes provides a superior performance in terms of the specific capacitance, rate capability and resistance, showing critical role of an additional conductive layer on diatom surface. Moreover, by virtue of the unique 3-D structure, diatomite@TiO2@MnO2 electrode also displays a long cyclic stability (retain 94.1% after 2000 cycling) and a high coulombic efficiency (retain 98.2%-99.6% during 2000 cycling). The presented results show an enhanced supercapacitor behavior of the diatomite@TiO2@MnO2 electrodes prepared using a low-cost natural diatomite material and simple scalable process and confirm their evident potential for energy storage/conversion applications.

Experimental evidence for rock layering development by pressure solution

Research Article| October 01, 2015 Experimental evidence for rock layering development by pressure solution Jean-Pierre Gratier; Jean-Pierre Gratier 1ISTerre, Université Grenoble Alpes, 38041 Grenoble Cedex 9, France2ISTerre, CNRS, 38041 Grenoble Cedex 9, France Search for other works by this author on: GSW Google Scholar Catherine Noiriel; Catherine Noiriel 3Géosciences Environnement Toulouse, Observatoire Midi-Pyrénées, Université Paul Sabatier, CNRS, IRD, 31400 Toulouse, France Search for other works by this author on: GSW Google Scholar François Renard François Renard 1ISTerre, Université Grenoble Alpes, 38041 Grenoble Cedex 9, France2ISTerre, CNRS, 38041 Grenoble Cedex 9, France4Physics of Geological Processes, Department of Geosciences, University of Oslo, 0316 Oslo, Norway Search for other works by this author on: GSW Google Scholar Author and Article Information Jean-Pierre Gratier 1ISTerre, Université Grenoble Alpes, 38041 Grenoble Cedex 9, France2ISTerre, CNRS, 38041 Grenoble Cedex 9, France Catherine Noiriel 3Géosciences Environnement Toulouse, Observatoire Midi-Pyrénées, Université Paul Sabatier, CNRS, IRD, 31400 Toulouse, France François Renard 1ISTerre, Université Grenoble Alpes, 38041 Grenoble Cedex 9, France2ISTerre, CNRS, 38041 Grenoble Cedex 9, France4Physics of Geological Processes, Department of Geosciences, University of Oslo, 0316 Oslo, Norway Publisher: Geological Society of America Received: 17 Feb 2015 Revision Received: 29 Jul 2015 Accepted: 30 Jul 2015 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2015 Geological Society of America Geology (2015) 43 (10): 871–874. https://doi.org/10.1130/G36713.1 Article history Received: 17 Feb 2015 Revision Received: 29 Jul 2015 Accepted: 30 Jul 2015 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jean-Pierre Gratier, Catherine Noiriel, François Renard; Experimental evidence for rock layering development by pressure solution. Geology 2015;; 43 (10): 871–874. doi: https://doi.org/10.1130/G36713.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Natural deformation of rocks is commonly associated with development of mineralogical layering, leading to irreversible transformations of their microstructure. The mechanisms of such chemical differentiation processes during diagenesis, tectonics, metamorphism, or fault differentiation remain poorly understood, as they are difficult to reproduce experimentally due to the very slow kinetics involved. This paper shows that development of differentiated layering, similar to that observed in natural deformation, is stress driven and can be obtained from indenter experiments. Samples of (1) gypsum plaster mixed with clay, and (2) natural diatomite loosely interbedded with volcanic ash, saturated with aqueous solutions in equilibrium, were subjected to loading for several months at 40 °C and 150 °C, respectively. X-ray microtomography and scanning electron microscopy observations show that layering develops by a self-organized pressure solution process. Stress-driven dissolution of the soluble minerals (either gypsum or silica) is initiated in the areas initially richer in insoluble species (clay or volcanic ash), as diffusive mass transfer along the interface between soluble and insoluble minerals is much faster than along the healed boundaries of the soluble minerals. The passive concentration of the insoluble minerals amplifies the dissolution along layers oriented perpendicularly to the maximum compressive stress. Conversely, in areas with an initial low content of insoluble minerals and clustered soluble minerals, dissolution is slower. Consequently, these areas are less deformed; they host the re-deposition of the soluble species and act as rigid objects that concentrate both stress and dissolution near their boundaries, thus amplifying the differentiation and the development of layered microstructures. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

The Fenton-like oxidation of the anionic azo-dye Orange II (100–500mg/L) was batchwise performed using commercial grade diatomites (3.5% Fe content) thermally treated.Solid samples were thoroughly characterized by several techniques. Peroxidation experiments were performed varying the diatomite calcination temperature (500, 700, 1000°C), reaction temperature (50, 60, 70, 80°C), catalyst load (0.47, 0.94, 1.89 and 3.78g), H2O2 concentration (11.0, 13.7, 20.6mmol/L) and dosing, pH (2–3.5) and initial dye concentration (0.28, 0.57, 1.43mmol/L). The influence of NaCl and oxalic acid on the catalytic performance and stability was also addressed.The best results were obtained with samples calcined at 700°C, with initial pH 3, at 70°C and using the stoichiometric amount of H2O2, since complete decoloration, TOC reduction close to 67% and negligible Fe leaching were achieved. The stability of the catalyst maintains after 20h of usage, with a final Fe loss of 2.25%. An average of 0.88mg/L of iron leached after each run, which is below the discharge limit.

Immobilization of radioactive borate liquid waste using natural diatomite

In this article, influence of diatomite as a natural adsorbent in immobilization of radioactive borate liquid waste in the cement-diatomite matrix was investigated. Cylindrical concrete mixtures were prepared with different amounts of diatomite additives at three different w/c values. Mechanical strength tests were carried out to determine the uniaxial compressive strength of the samples. A new dynamic column type leaching tests were applied to the solidified waste forms, and leach rates of 137Cs and 60Co were determined according to different diatomite additives. The experimental results indicated that the increasing of the diatomite additive amounts resulted high isolation performance of the solidified waste form. However, the results revealed that mechanical strength decreases with increasing borate diatomite amount. Results show that 9% amount of natural diatomite is effective as an admixture of the cementation process for achieving long-term stability of solidified borate waste. Optimum strength and leach values were determined as 11.5 MPa with leaching rates of 7.5 × 10−4 and 3.2 × 10−5 cm/d for 137Cs and 60Co, respectively.

Modified natural diatomite and its enhanced immobilization of lead, copper and cadmium in simulated contaminated soils

Natural diatomite was modified through facile acid treatment and ultrasonication, which increased its electronegativity, and the pore volume and surface area achieved to 0.211cm3g−1 and 76.9m2g−1, respectively. Modified diatomite was investigated to immobilize the potential toxic elements (PTEs) of Pb, Cu and Cd in simulated contaminated soil comparing to natural diatomite. When incubated with contaminated soils at rates of 2.5% and 5.0% by weight for 90 days, modified diatomite was more effective in immobilizing Pb, Cu and Cd than natural diatomite. After treated with 5.0% modified diatomite for 90 days, the contaminated soils showed 69.7%, 49.7% and 23.7% reductions in Pb, Cu and Cd concentrations after 0.01M CaCl2 extraction, respectively. The concentrations of Pb, Cu and Cd were reduced by 66.7%, 47.2% and 33.1% in the leaching procedure, respectively. The surface complexation played an important role in the immobilization of PTEs in soils. The decreased extractable metal content of soil was accompanied by improved microbial activity which significantly increased (P<0.05) in 5.0% modified diatomite-amended soils. These results suggested that modified diatomite with micro/nanostructured characteristics increased the immobilization of PTEs in contaminated soil and had great potential as green and low-cost amendments.

Natural diatomite (Rudovci, Serbia) as adsorbent for removal Cs from radioactive waste liquids

The removal of Cs (I) ions from aqueous solution was studied using natural diatomite as adsorption materials originated from Rudovci, Serbia. The microstructure of natural diatomite has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) while the degree of Cs adsorption was evaluated by atomic emission spectroscopy. The cation exchange capacity (CEC) values for natural diatomite was 50 meq/100g. Depending on whether the Cs adsorption occurred in the acidic and alkaline media at a temperature of 298.15 K in acidic media ?G0 values was -12.674 kJ/mol, while in alkaline media ?G0 was - 13.142 kJ/mol and a change of ?S0 to 42.51 J/molK in acidic media and 44.08 J/molK in alkaline medium.

Liquid Phase adsorption kinetics and equilibrium of toluene by novel modified-diatomite.

The adsorption equilibria of toluene from aqueous solutions on natural and modified diatomite were examined at different operation parameters such as pH, contact time, initial toluene concentration was evaluated and optimum experimental conditions were identified. The surface area and morphology of the nanoparticles were characterized by SEM, BET, XRD, FTIR and EDX analysis. It was found that in order to obtain the highest possible removal of toluene, the experiments can be carried out at pH 6, temperature 25°C, an agitation speed of 200 rpm, an initial toluene concentration of 150 mg/L, a centrifugal rate of 4000 rpm, adsorbent dosage = 0.1 g and a process time of 90 min. The results of this work show that the maximum percentage removal of toluene from aqueous solution in the optimum conditions for NONMD was 96.91% (145.36 mg/g). Furthermore, under same conditions, the maximum adsorption of natural diatomite was 71.45% (107.18 mg/g). Both adsorption kinetic and isotherm experiments were carried out. The experimental data showed that the adsorption follows the Langmuir model and Freundlich model on natural and modified diatomite respectively. The kinetics results were found to conform well to pseudo-second order kinetics model with good correlation. Thus, this study demonstrated that the modified diatomite could be used as potential adsorbent for removal of toluene from aqueous solution.

Characterizations and performances of Ni/diatomite catalysts for dry reforming of methane

Monometallic 5wt% Ni containing catalysts were prepared by a two-solvent (cyclohexane/water) deposition method using cheap and widely available natural diatomites (Ni/AW2 and Ni/MN3) as supports. The fresh samples were characterized by SEM, EDX microanalysis, N2 adsorption–desorption isotherms, XRD and tested after reduction (in hydrogen) in dry reforming of methane. Spent catalysts were further characterized by TPH coupled with mass spectrometry. Although slightly less active than a reference Ni/Aerosil (Ni/SiO2) catalyst prepared in similar conditions, the Ni/diatomites catalysts showed good activity with 90% methane conversion reached on Ni/MN3 at 800°C and a high selectivity towards dry reforming reaction (H2:CO molar ratio around unity over the entire temperature range). The catalysts were also relatively stable during catalytic measurements conducted at 650°C for 12h. In addition, depending on the nature of the diatomite and on the conditions of thermal activation, carbon deposits with lower toxicity (easier to remove by reactivation) than those formed on the Ni/Aerosil were obtained.

One-step synthesis of highly ordered Pt/MCM-41 from natural diatomite and the superior capacity in hydrogen storage

Platinum-loaded mesoporous silica (xPt/MCM-41) with highly ordered structures and narrow pore size distributions were successfully synthesized via one-step hydrothermal method from natural diatomite. The samples were characterized using X-ray diffraction, nitrogen adsorption–desorption, X-ray photoelectron spectroscopy and transmission electron microscopy. Hydrogen adsorption capacities of the samples were also investigated at room temperature. The samples display uniformly arrayed hexagonal pore structure in two-dimension with pore size around 3nm. Zero-valent Pt nanoparticles were synthesized and stabilized by the confinement effect of ordered mesoporous MCM-41 without destroying the integrity of mesoporous structure in the one-step synthetic procedure. These xPt/MCM-41 materials were also concluded to be promising mediums for physisorption-based hydrogen storage at room temperature. The hydrogen adsorption capacity of 0.5Pt/MCM-41 is 2.32wt.% at 2.5MPa and 25°C, determined from the isotherms, which is among the highest reported values under the same conditions. Hydrogen storage was benefited by these highly dispersed Pt nanoparticles and the refined structure properties of MCM-41 at room temperature. Meantime, the composition, structure and surface characteristics of 0.5Pt/MCM-41 remained the same after hydrogen adsorption. The uniform mesoporous structure plays a decisive role in inhibition of agglomeration and confinement of nanoparticles. This one-step synthetic procedure could offer a more benign approach for the synthesis of noble metal functionalized MCM-41 potentially for hydrogen storage at room temperature.

Polyhydroxyl-aluminum pillaring improved adsorption capacities of Pb2+ and Cd2+ onto diatomite

In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum. A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property. The pillared diatomite attaining the optimal adsorption densities (qe) of Pb2+ and Cd2+ was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1–0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 °C for 120 min; aging at a temperature of 105 °C for 16 h. The adsorption capacities of Pb2+ and Cd2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.

Natural diatomite modified as novel hydrogen storage material

Natural diatomite, subjected to different modifications, is investigated for hydrogen adsorption capacities at room temperature. An effective metal-modified strategy is developed to disperse platinum ( Pt ) and palladium ( Pd ) nanoparticles on the surface of diatomite. Hydrogen adsorption capacity of pristine diatomite (diatomite) is 0.463 wt.% at 2.63 MPa and 298 K, among the highest of the known sorbents, while that of acid-thermally activated diatomite (A-diatomite) could reach up to 0.833 wt.% due to the appropriate pore properties by activation. By incorporation with a small amount of Pt and Pd (~0.5 wt.%), hydrogen adsorption capacities are enhanced to 0.696 wt.% and 0.980 wt.%, respectively, indicating that activated diatomite shows interesting application in the field of hydrogen storage at room temperature.

Enhanced Coagulation/Flocculation by Combining Diatomite with Synthetic Polymers for Oily Wastewater Treatment

The objectives are to evaluate the feasibility of treating oily wastewater using synthetic polymers (polyaluminum chloride (PAC), polyferric sulfate (PFS), and polyacrylamide (PAM)) combined with natural diatomite and to refine the operating parameters using diatomite as an adsorbent and a coagulant aid. The enhanced coagulation/flocculation by combining PAC with diatomite was investigated through mechanism analysis compared to the combination of PFS/PAM with diatomite, respectively. The effects of coagulant dose, initial pH, and settling time on chemical oxygen demand (COD) and turbidity were studied using PAC-diatomite in comparison with using PAC only. The enhanced coagulation/flocculation of diatomite with PAC was better than that with PFS/PAM in terms of COD/turbidity removal and floc settling characteristics, considering costs. The PAC-diatomite system reduced more than 70% of COD and 90% of turbidity over a wide pH range (7–10) within 20 min, with the optimum dose of PAC 50 mg/l and diatomite 1250 mg/l. The added diatomite effectively saved over 85% of PAC dose and simultaneously increased over 50% of COD removal efficiency. This study provided a novel and economical approach for diatomite utilization in the treatment of oily wastewater, satisfying the demands of reuse or reinjection into the ground.

Thermodynamics and adsorption studies of dye (rhodamine-b) onto natural diatomite

Thermodynamics and adsorption studies were conducted with a dye of rhodamine-B on natural diatomite. Adsorption of the dye was investigated with an initial dye concentration at pH 8±0.2, 303, 313 and 323 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The kinetic data agreed with the pseudo-first order model with rate constants (k2) in the range of 3.05-1.59.10 -1 g/mg min. The thermodynamic parameters such as standard free energy, entropy change and enthalpy were calculated for natural diatomite. These values showed that adsorption of rhodamine-B on natural diatomite was a spontaneous and endothermic process.

Proton Conductivity of Natural Diatomite

ABSTRACTProton conductivity of the natural diatomite was studied by ac complex impedance technique. At room temperature, the highest proton conductivity was found to be 4.5 x 10-7S·cm-1. By hydrating the diatomite, the proton conductivity was increased to two orders of magnitude higher. The room temperate proton conductivity of the hydrated diatomite (5.5 x 10-5S·cm-1) was comparable to other hydrated solid proton conductors. The natural diatomite could be used as potential cost-effective proton conductor for electrochemical applications.