Use Of Natural Clay Research Articles

Role of silicate-rich and silicate-less industrial solid wastes in the physicomechanical properties and durability of low quality metakaolin-blended cement.

Although calcined clay-blended cement offers higher performance and durability compared to neat Portland cement (PC), its extensive use of natural clay leads to the depletion of natural non-renewable resources. To address this concern, this study focuses on the utilization of supplementary cementitious materials-based waste products as a substitute for PC. The blended cement was optimized with a low replacement level of 10 wt.% calcined Fanja clay (FNJ) as a low-grade metakaolin (MK) and 90 wt.% PC. Various types of industrial solid wastes (ISWs) were incorporated into the PC-FNJ blend in place of PC. The ISWs utilized included silicate-rich wastes, such as silica fume (SF) and glass waste (GW) powder, as well as silicate-less waste, such as marble dust (MD). The results revealed that incorporating 10 wt.% SF into the PC-FNJ mixture resulted in a considerable decrease in the flow rate while improving its early mechanical strength. GW, as another silicate waste, also enhanced early mechanical properties but not as much as SF. However, the composite of PC-FNJ-GW exhibited higher workability than the neat PC, PC-FNJ, and PC-FNJ-SF. The mixtures of PC-FNJ-MD demonstrated the same trend. Embedding SF into PC-FNJ-GW and PC-FNJ-MD substantially decreased both their flowability and mechanical properties. Nonetheless, all composites containing ISWs showed higher flexural strength, higher resistivity to chloride diffusivity, and higher or comparable acid and salt resistivity.

Treatment of real textile effluent containing indigo blue dye by hybrid system combining adsorption and membrane processes

The rapid expansion of the textile industry in Tunisia has resulted in ever-increasing discharges of wastewater, making it necessary to set up treatment systems allowing i) its discharge into the environment or ii) to recycle the water in the textile plant. In this study, several unitary operations were tested in order to improve the treated water quality. Thus, the following unit operations were applied: adsorption using Natural Clay (NC) and Powdered Activated Carbon (PAC), ultrafiltration (UF) and nanofiltration (NF) individually or in synergy: UF, nanofiltration, PAC-UF, NC-UF, UF-NF et Adsorption-UF/NF. The experiments were carried out on real textile effluent containing Indigo blue dye. A threshold concentration was observed above which performance no longer increases. NF alone showed better reduction of COD (67%), color (78%), and turbidity (98%) than UF alone (26%, 48%, 95%, respectively). The coupling UF–NF showed a clear improvement in water quality in terms of color (99%) and COD (98%) with an improvement in the NF flux from 67.81 L/h.m2 to 90.62 L/h.m2. No fouling was observed for NF while it is significant during UF. The used of adsorption as pretreatment to filtration leads to an enhancement of the treatment performances with a removal of 99.9%, 99.5% and 79.5% respectively for turbidity, color and COD for NC-UF and a removal of 100%, 99.4% and 79.6% respectively for turbidity, color and COD for PAC-UF. Moreover, the addition of adsorbent controls the fouling and a constant and high flux is quickly attained and remains stable over time. The use of natural clay as adsorbent represents an economically profitable solution since it can be obtained locally and the clay used can be reused in the ceramic industry as an additive for road surfacing without the need for regeneration.

ТНЕ INVESTIGATION OF PERFORMANCE CHARACTERISTICS OF SAPONITE GRANULATE

The use of natural clays in production and environmental protecting measures is provided by their mineral compounds, physical and chemical properties which are defined by the composition and size of clay part. In terms of ecology that is expedient, as the clay minerals almost don’t have compounds that pollute waters and they are natural for such areas. It has been investigated the problems of the Ukrainian market of petroleum products and suggested the ways to solve them by developing of a program for the transition to Euro environmental standards and alignment of Ukrainian standards with the European ones. The influence of the granulation process on the sorption properties of the obtained granulated aluminosilicates has been investigated. The main operational characteristics of the received saponite granulate namely: the stability and strength of the granules in gasoline over a given period of time; it has been evaluated the water resistance and oil capacity of sorption materials based on layered aluminosilicates. It has been shown that the activation of natural sorption materials with acids does not significantly affect the indicators of heat resistance and destruction processes in the saponite-activator system. Moreover, granulation improves the strength and filtration characteristics of natural sorbents by increasing the filtration rate. The results of the research allow us to recommend the obtained sorbent materials as an efficient filtering charge for cleaning and controlling specific properties as a filter load for cleaning hydrocarbon mixtures and for obtaining high-quality, high-octane and low-toxic fuels. It was established that the obtained sorption material based on saponite clay improves the basic exploitative characteristics of the fuel. Its application allow to solve the problem of reducing toxic emissions of e.g. motor vehicles in atmosphere.

Application of Clay Materials for Sorption of Radionuclides from Waste Solutions

The wide application of nuclear resources in various fields has resulted in the production of radioactive waste, which poses a serious threat to lives and the environment. Nuclear waste contains long-lived radionuclides and, due to its mobility in environments, the proper management of generated waste is necessary. To impede the mobility of radionuclides in environments, various materials have been tested as suitable sorbents under different experimental conditions. In this review, we thoroughly discuss some key and recent contributions to the application of natural clays (NCs) and modified/functionalized clays (MCs) for the sorption of various radionuclides in their cationic and anion forms from (simulated) waste solutions under different experimental conditions. More specifically, we discuss the key developments toward the use of natural clays for the efficient sorption of various radioactive contaminates. Later, this review targets the modification/functionalization of natural clays using various organic moieties to improve their removal capacities for various radionuclides/hazardous ions present in waste solutions. Finally, we summarize the major aspects and highlight the key challenges to be addressed in future studies to further enhance the application of clays and clay-based materials for selective and effective removal of various radionuclides from waste solutions.

Pillared clay-based catalysts for treatment of 4-nitrophenol solutions by catalytic wet peroxide oxidation

<p>The constant development of technological processes aggravates the problem of pollution, due to a significant change in the composition of effluents, which makes necessary new (and/or improved) treatment methods and catalytic materials. In this sense, the use of natural clays in the synthesis of low-cost pillared clays for application as catalysts in oxidation technologies for the treatment of wastewaters is relevant from an environmental and sustainable point of view. In this work, inexpensive natural clays from different regions of Kazakhstan (Akzhar, Karatau, and Kokshetau) were used in the preparation of pillared clays for the catalytic oxidation of organic pollutants with H2O2. Since nitrophenols are commonly found in many types of industrial wastewaters (e.g. plastic, pharmaceutical, paper, or pesticides industries), 4-nitrophenol (4-NP) was used as a representative model compound in the catalyst screening studies. The pillaring process of the targeted natural clays involved the incorporation of active metals such as Zr, Fe, and Cu, which were responsible for increasing the catalytic activity of the materials relative to the natural clays. High conversions of TOC (85%) and of 4-NP (100%) were obtained with the Zr-pillared clay from the Akzhar region.</p>

Copper-containing magnetite supported on natural clay as a catalyst for heterogeneous photo-Fenton degradation of antibiotics in WWTP effluent

The use of natural clay as a support for magnetite and copper-containing magnetite was evaluated for heterogeneous Fenton/photo-Fenton degradation of trimethoprim and sulfamethoxazole. In Fenton experiments, the incorporation of copper ions on magnetite played an important role in the decomposition of hydrogen peroxide. Photo-Fenton experiments were performed under solar and UV-LED (370 nm) irradiation, with complete degradation of both antibiotics in purified water achieved under solar irradiation. Evaluation of the effects of inorganic anions and organic carbon showed that the highest •OH scavenging was due to CO32-/HCO3- and organic matter content. From a practical perspective, treatment of wastewater treatment plant effluent under solar irradiation resulted in 52% and 41% degradation of TMP and SMZ, respectively, together with 15% removal of dissolved organic carbon. The material maintained efficiency during 3 reuse cycles, showing its potential for use as a low-cost catalyst. The intermediates identified by UHPLC/MS indicated that TMP degradation involved hydroxylation, demethylation/hydroxylation, and cleavage pathways, while SMZ degradation involved hydroxylation, breaking of the sulfonamide bond, and opening of the isoxazole ring.

Clay, Zeolite and Oxide Minerals: Natural Catalytic Materials for the Ozonation of Organic Pollutants.

Ozone has been successfully employed in water treatment due to its ability to oxidize a wide variety of refractory compounds. In order to increase the process efficiency and optimize its economy, the implementation of heterogeneous catalysts has been encouraged. In this context, the use of cheap and widely available natural materials is a promising option that would promote the utilization of ozone in a cost-effective water treatment process. This review describes the use of natural clays, zeolites and oxides as supports or active catalysts in the ozonation process, with emphasis on the structural characteristics and modifications performed in the raw natural materials; the catalytic oxidation mechanism; effect of the operating parameters and degradation efficiency outcomes. According to the information compiled, more research in realistic scenarios is needed (i.e., real wastewater matrix or continuous operation in pilot scale) in order to transfer this technology to the treatment of real wastewater streams.

Experimental Simulation of Sorption Processes of Heavy Metals on Natural Clay Minerals

The sorption of iron (III) and copper (II) ions on natural clay minerals of deposits of Buryatia is investigated. The adsorption of ions of these metals depends on pH of solution, clay loading, concentration of metals ions and also on the temperature of adsorption carrying out and regularities of influence of these parameters on adsorption efficiency are determined. Kinetic regularities of adsorption of ions of Fe3+ and Cu2+ on natural clays are consistent with kinetics model of pseudo- second order. The isotherms of equilibrium adsorption of above-mentioned ions on natural clay are described by Langmuir equation with the correlation coefficient of R2 equal 0.994. Results of testing of clays in the process of purification of adit wastewater of iron and copper ions testify to a possibility of effective use of natural clays of Buryatia in sewage treatment from ions of heavy metals.

Natural aluminosilicate clay obtained from south-eastern Nigeria as potential sorbent for oil spill remediation

Few reports exist on the use of natural inorganic sorbents such as clays compared to organic biomass materials for crude oil sorption. Also, the mechanistic kinetic, isotherm and thermodynamics have seldom been discussed in the few clay oil sorption studies available. This work evaluated the use of Natural Clay (NC) for removal of crude oil from solution. The sorbent was characterized by the Fourier transform infrared, scanning electron microscope, X-ray diffraction, X-ray fluorescence and Brunauer-Emmett-Teller surface area analyzer. The chemical oxide composition revealed SiO2 (53.1%) and Al2O3 (19.8%) as major components of NC and cation exchange capacity of 76.1 mEq/100 g. The Langmuir model presented the best fit with higher R2 of 0.981 and lower Sum square error (SSE) of 0.21 compared to the Freundlich and Tempkin isotherm. The pseudo-first order model was found to be applicable compared to the pseudo-second order kinetic analysis, with intra-particle diffusion mechanism involved in the removal process. Thermodynamics revealed a spontaneous, endothermic and physical sorption of crude oil on NC. The sorption capacity of NC for crude oil was found to be higher than most sorbents reported in literature. NC showed good regeneration and reusability for crude oil removal using n hexane after three cycles of sorption-desorption experiment The study indicated enormous potentials of NC as low cost sorbent for oil spill treatment.

Табиғи сазбалшықтардың катализде қолданылуы

Рациональное использование природных ресурсов является одним изважных проблем современного Казахстана. В этом плане природные глины представляютособый интерес для синтеза новых катализаторов, сорбентов и носителей. В данной статьепредставлен обзор сведений об использовании природных глин в области каталитическойхимии в качестве катализаторов, адсорбентов и носителей. По результатам исследованиявыяснилось, что, использование природных модифицированных глин в катализе поможетрешить вопросы развития отечественного производства синтеза катализаторов, адсорбентови носителей, замены их дорогих импортных аналогов.

Natural clay from Cuba for environmental remediation

ABSTRACTThe use of natural clays for the removal of dyes from wastewater, an important part of environmental remediation, is desirable due, not least, to their low cost. Palygorskite (PAL), a rigid-structure clay, is a good candidate for use in the elimination of industrial effluents, based on its exceptional adsorptive properties. Recently, a new palygorskite deposit has been discovered in Cuba and its use in the adsorption of dyes has not yet been explored in detail. In the present study, the use of unmodified natural Cuban palygorskite as a host for dyes was evaluated. Congo red (CR) and methylene blue (MB) were the anionic and cationic dyes tested, respectively, because of their wide use and toxicity to the environment. Several physical-chemical parameters were studied in order to establish the best experimental conditions under which to achieve the greatest dye load per gram of clay. Natural mixtures with different percentages of montmorillonite were also tested to evaluate their effect on the adsorption of the dyes. The results indicated that at pH values of ~7–9 and an initial dye concentration of 0.1 mg mL–1, the process was efficient. X-ray diffraction (XRD) analysis proved the surface adsorption of both dyes on the clays. The main interactions involved in the clay-dye system were electrostatic forces and H-bonds. Adsorption of CR seemed to be controlled fundamentally by the palygorskite phase. Such results support the use of this natural clay as an efficient host for the removal of MB and CR from wastewater.

A comparative study of the effect of clay and titanium dioxide on the mechanical properties and permeability of nanocoated cotton fabrics

ABSTRACTThis paper explores a comparison of mechanical properties of nanocoated cotton fabric for coatings synthesized with two different additives: Tunisian natural clay and titanium dioxide. The natural raw clay is a mixture of various other simple clays (kaolinite, calcite, illite, and quartz) requires preparation. TiO2 and Tunisian clay were added to two different resins, polyacrylate and polyurethane, widely used for numerous textile improvements such as impermeability and brightness effects. The additives used offer the advantage of being nontoxic and widely available. First, we check the constitution of the nanocoatings via X‐ray diffraction. Then, a defined amount of the resulting solution is applied on a cotton fabric. Finally, we check the mechanical properties and barrier effects on the modified fabric. The results show that when a small amount of clay or TiO2 particles are added to resin, the tear, tensile, bursting, and abrasion strength and water and air barrier properties of the coated fabric are globally enhanced. However, the use of natural clay in the coating gives better results than TiO2. In fact, in terms of mechanical performance, it is two to nine times more efficient than the titanium dioxide coating, except for the barrier effect, which is exactly two times more efficient. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45642.

A natural clayey adsorbent for selective removal of lead from aqueous solutions

Natural clay minerals are an inherently colorless class of materials, which have long been known for their versatility as adsorbents due to their interchange capacity, large catalytic support, great surface area, and low cost. Herein, we have reported the use of natural clay, collected from the Gabes area, southern Tunisia (Early Cretaceous) for selectively capturing of lead ions from aqueous environments. Our results showed that natural clay samples were mainly composed of silica, alumina, iron and magnesium oxides. Adsorption data showed that the studied clay samples preferably removed substantial amounts of lead ions from water. The removal efficiency of lead ions was about 86.4mg/g of clay and followed pseudo-second-order kinetics. More than 95% of the total adsorptive capacity occurred within 30min. These results suggest the Early Cretaceous clays, Tunisia, turned out to be an effective natural adsorbent for capturing of lead ions from aqueous environment.

Study of Adsorption and Flocculation Properties of Natural Clays to Remove Prorocentrum lima.

High accumulations of phytoplankton species that produce toxins are referred to as harmful algal blooms (HABs). HABs represent one of the most important sources of contamination in marine environments, as well as a serious threat to public health, fisheries, aquaculture-based industries, and tourism. Therefore, methods effectively controlling HABs with minimal impact on marine ecology are required. Marine dinoflagellates of the genera Dinophysis and Prorocentrum are representative producers of okadaic acid (OA) and dinophysistoxins responsible for the diarrhetic shellfish poisoning (DSP) which is a human intoxication caused by the consumption of shellfish that bioaccumulate those toxins. In this work we explore the use of natural clay for removing Prorocentrum lima. We evaluate the adsorption properties of clays in seawater containing the dinoflagellates. The experimental results confirmed the cell removal through the flocculation of algal and mineral particles leading to the formation of aggregates, which rapidly settle and further entrain cells during their descent. Moreover, the microscopy images of the samples enable one to observe the clays in aggregates of two or more cells where the mineral particles were bound to the outer membranes of the dinoflagellates. Therefore, this preliminary data offers promising results to use these clays for the mitigation of HABs.

Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters

Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH.The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption–desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk.The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP–OES) analyses.The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture≈50%, release≈70%) is obtained when the uptake and release processes are performed at pH=5 and pH=1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium.

Microwave-induced catalytic degradation of a textile dye using bentonite–poly(o-toluidine) nanohybrid

The present study highlights the potential use of natural clay based organic–inorganic hybrids as eco-friendly catalysts for the degradation of Malachite Green under microwave irradiation.

Dispatches

Dispatches

Management of old landfills by utilizing forest and energy industry waste flows

The lack of landfill capacity, forthcoming EU waste disposal and landfill management legislation and the use of non-renewable and energy intensive natural resources for the end-treatment of old landfills increase pressures to develop new landfill management methods. This paper considers a method for the end-management of old landfills in Finland, which is based on the utilization of forest and paper industry waste flows, wastes from paper recycling (de-inking) and wastes from forest industry energy production. Fibre clay wastes from paper mills, de-inking sludges from de-inking of recovered waste paper and incineration ash from forest industry power plants serve to substitute the use of natural clay for the building of landfill structures for closed landfills. Arguably, this method is preferable to existing practices of natural clay use for landfill building, because it (1) substitutes non-renewable natural clay, (2) consumes less energy and generates less CO2 emissions than the use of natural clay, and (3) eliminates considerable amounts of wastes from paper production, paper consumption and from forest industry energy production. Some difficulties in the application of the method are considered and the waste flow utilization is incorporated into a local forest industry recycling network.

Spray-dried calcined clays in water filtration columns used for chromium removal

Well-rounded grains are normally used as filtration media, because the spherical shape seems to be most suitable to get rapid and efficient removal operations. In this sense, the direct use of natural clays as filtration media is problematic, due to the plate-type shape of the particles. In this work, rounded grains of two natural clays processed by spray-drying are tested as filtration media. The settling regime of the grains in a filtration column was determined and the chromium removal from water was also tested. Sieved fractions now used (355–1680 μm) show settling behavior according to the transition regime. Preliminary results of chromium removal by the selected 355–420 μm sieved fraction bed show interesting capabilities for the Cr3+ species, while chromate (VI) retention is extremely low.