The clay mineral attapulgite derives its non-swelling needle-like morphology from its three-dimensional crystal structure. The shape and size of the needles result in unique colloidal properties, especially resistance to high concentrations of electrolytes, and give high surface area, high porosity particles when thermally activated. Examples of industrial applications of attapulgite are reviewed with emphasis on how these characteristic properties function in the various end-uses.

Biocatalysts and ILs have become useful partners, and the properties of ILs are frequently desired to improve bioprocesses employing whole-cell and isolated enzyme biocatalysts. As new technologies are being developed to feed the emerging sustainable chemical and energy industries, biocatalysis will take an increasingly important role, as these methods allow humans to achieve remarkable chemical transformations without requiring rare elements or lengthy synthetic methods. The application of biocatalysis in energy and chemicals requires the production of robust catalysts and devices, and ILs can have a profound impact in this area.

This chapter has provided a snapshot of the potential benefits of ILs in bioprocesses. These applications are all at different stages of research and development, with the application of isolated enzymes and ILs to the conversion of biomass being the most developed. All of the uses cited have the potential to contribute significantly to a lower carbon future. Much more work in this area is anticipated throughout the coming decades.

The fields of biocatalysis and ILs are both rapidly evolving, and we can only imagine what will be possible in the future, and how researchers will rise to the challenges of creating a greener future.

As most pesticides are either insoluble or only slightly soluble in water and must be applied in relatively small amounts over large areas, they are formulated in such a way that a highly concentrated organic chemical can be put into a convenient-to-use and effective form for field use by blending it with additives and inert carriers. The formulation must be easy and economical to use, do the job it is meant for, have an adequate shelf-life, and have no undesirable side effects. In solid-based formulations, the inert materials used, called diluents or carriers, can be either botanicals (e.g., ground corn cobs, walnut shells), synthetics (both organic and inorganic), or minerals (carbonates, oxides, and clays). In 1976 nearly 300,000 tons of various clays were delivered to pesticide manufacturers in the United States alone for use in pesticide formulations (U.S. Department of Agriculture 1976). Of this amount, over 65% was attapulgite. The predominance of attapulgite in the formulation of pesticides in preference to more common clay minerals such as kaolinite and montmorillonite stems from the fact that it is not easily flocculated by electrolytes and does not cake at high relative humidities but remains free-flowing (HADEN and SCHWINT1967).

The name attapulgite was applied in 1935 by J. De Lapparent1 to a clay mineral which he encountered in fuller's earths from Attapulgus, Georgia, and Mormoiron, France. Objections have been raised, and these objections were recently reviewed by De Lapparent,2 that the material involved does not justify the application of a mineral name. However, no attempt has been made to study the crystal structure. De Lapparent himself has suggested for classification purposes that attapulgite is a layer silicate related to the micas, but some obvious inconsistencies with the x-ray powder diffraction patterns of the mineral have suggested the desirability of attempting a better explanation. The material used in this investigation was obtained from the Attapulgus Clay Co., Attapulgus, Ga. The raw clay was dispersed and freed of large crystalline impurities by sedimentation. Centrifuge fractions were then obtained, of which particularly the fraction between .1 and .05μ appeared homogeneous and showed no extraneous lines in its diffraction diagram. Flakeshaped aggregates of this material were employed in obtaining the subsequent data. The chemical analyses and optical data given in Table 1, and the powder diffraction diagram in Fig. 1 leave no doubt of the identity of this material with that originally described by De Lapparent.

,It is to be understood, that as used hereinafter, the term pesticide or pesticidal composition is meant to refer to those toxicant compositions which are effective in killing or controlling the growth of plants, insects, microorganisms, fungi, bacteria and the like, and it is intended to refer broadly to those compositions commonly known as insecticides, bactericides, fungicides, nematocides, herbicides and the like.
Various types of pesticides have been proposed and are currently in use. These materials are characterized by their ability to attack or exterminate certain undesirable species of pests, their action being selective in that desirable species are left substantially unaffected and in a more or less healthy or vigorous state. The pesticidal compositions which have been used include both inorganic and organic chemicals or compositions, some of the more common materials being the following:

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​Attempts have been made to solve these problems by incorporating the pesticidal agents into or upon pellets consisting essentially of fullers earth, natural clays, such as, attaclay, pumice, calcined diatomaceous earth, or other pelletized powders. While such pellets lend themselves to control distribution by aircraft over a designated area, they leave much to be desired in that the bonding agents employed during the pelletizing operations are usually water soluble. The pellets are, therefore, adversely affected by rainfall or conditions of high humidity which cause slacking and progressive disintegration of the pellets. During periods of reduced humidity 01' drought, the resulting disintegrating pelletsform dust which may be picked up by prevealing winds, thereby causing damage to adjacent areas where the presence of such agents would be undesirable. Furthermore, the disintegration of such pellets accelerates the release of the pesticidal agents and the effective life or period activity of the pelletized composition is thereby substantially reduced.

Adsorption of parathion by pretreated attapulgites was studied in both organic andaqueous media. In organic media the presence of hygroscopic moisture resulted in competition between parathion and water so that an increase inthe clay’s moisture content reduced parathion adsorption. Heating the clays above 250 C resultedin structural changes that cause a decrease in parathion adsorption. Adsorption of parathion in aqueous solution was found to be inversely related to the release of parathion from highly loaded clays under equilibrium conditions. Saturating clays with an organocation altered their properties favoring increased adsorption and decreased desorption. The results indicate that pretreatment of the clay might affect both the rate and amountof release to the external environment.
For insoluble or slightly soluble pesticides, dust formulations are commonly used to achieve uniform application to the soil surface; the desired compound is added in combination with a solid diluent (Polon, 1973). Attapulgite is one of the clays commonly used. This mineral is a fibrous clay which differs from the more common layer silicates (montmorillonite, kaolinite) in that it does not consist of discrete platelets, but rather has a rigid three-dimensional structure with microchannels (3.5 X6

Clay minerals are naturally occurring rock and soil materials primarily composed of fine-grained aluminosilicate minerals, characterized by high hygroscopicity. In animal production, clays are often mixed with feed and, due to their high binding capacity towards organic molecules, used to limit animal absorption of feed contaminants, such as mycotoxins and other toxicants. Binding capacity of clays is not specific and these minerals can form complexes with different compounds, such as nutrients and pharmaceuticals, thus possibly affecting the intestinal absorption of important substances. Indeed, clays cannot be considered a completely inert feed additive, as they can interfere with gastro-intestinal (GI) metabolism, with possible consequences on animal physiology. Moreover, clays may contain impurities, constituted of inorganic micronutrients and/or toxic trace elements, and their ingestion can affect animal health. Furthermore, clays may also have effects on the GI mucosa, possibly modifying nutrient digestibility and animal microbiome. Finally, clays may directly interact with GI cells and, depending on their mineral grain size, shape, superficial charge and hydrophilicity, can elicit an inflammatory response. As in the near future due to climate change the presence of mycotoxins in feedstuffs will probably become a major problem, the use of clays in feedstuff, given their physico-chemical properties, low cost, apparent low toxicity and eco-compatibility, is expected to increase. The present review focuses on the characteristics and properties of clays as feed additives, evidencing pros and cons. Aims of future studies are suggested, evidencing that, in particular, possible interferences of these minerals with animal microbiome, nutrient absorption and drug delivery should be assessed. Finally, the fate of clay particles during their transit within the GI system and their long-term administration/accumulation should be clarified.

The structure and hydration status of attapulgite clay after heating at elevated temperatures and the stability of parathion on these clays was studied. Using infrared spectroscopy and scanning electron microscopy it was found that the bound water was lost in two steps, at 250° and 450° with the first step being largely reversible. At 650°C the structure began to dissolve releasing significant amounts of Mg, and a decrease in aggregate porosity was noted. At 850°C an amorphous phase was formed bearing little resemblance to the original attapulgite. Parathion was stable on all of the preheated clays when kept at 25°C for 190 days. The reactions of parathion on the preheated clays was studied at 110°C Hydrolysis of parathion was found to be minimal. Isomerization was the main reaction occurring on the Ca-attapulgite, whereas on an organo-clay no isomerization was observed. A mechanism for the isomerization reaction is proposed which entails a distortion of the phosphate moiety of the pesticide by the oxygen of the ligand water resulting in the conformational changes necessary for the isomerization to take place. On the organo-clay such a conformation was not possible; hence no isomerization occurred.РезюмеИсследовались структура и состояние гидратации аттапулгитовой глины после нагревания при повышенных температурах, а также стабилность паратиона на этих глинах. Путем инфракрасной спектроскопии и электронного сканирующего микроскопа было обнаружено, что связанная вода освбождалась в двух этапах, при температурах 250°С и 450°С, причем первый этап был преимущественно реверсивный. При 650°С структура начинала растворяться, освобождая значительное количество магния, а также наблюдалось уменьшение пористости аггрегатов. При 850°С формировалась аморфная фаза, которая только в небольшой степени напоминала исходный аттапульгит. Паратион был стабильный на всех предварительно нагретых глинах, если они содержались при температуре 25°С в течение 190 дней. Реакции паратиона на нагретых глинах были исследованы при температуре 110°С. Гидролиз паратиона был минимальный. Изомеризация являлясь главной реакцей для Са-аттапульгита, в то время, как она не наблюдалась для органоглины. Для реакции изомеризации предложен механизм, который определяет искажение фосфатовой половины пестицида кислородом аддендовой воды, результатом чего является изменение формы необходимые для изомеризации. Для органо-глины такая форма невозможна, и в этом случае изомеризация не происходит. [Е.С.]ResümeeEs wurde der Struktur- und Hydratationszustand von Attapulgit-Ton nach dem Erhitzen auf erhöhte Temperaturen sowie die Stabilität von Parathion an diesen Tonen untersucht. Die Untersuchungen mit Infrarotspektroskopie und Rasterelektronenmikroskopie zeigten, daß das gebundene Wasser in zwei Schritten, bei 250°C und 450°C abgegeben wurde, wobei der erste Schritt in hohem Maße reversibel war. Bei 650°C begann die Struktur sich zu veräindern, indem sie beträchtliche Mengen an Magnesium vedor. Weiters wurde eine Abnahme der Aggregatporosität festgestellt. Bei 850°C wurde eine amorphe Substanz gebildet, die sehr wenig Ähnlichkeit mit dem ursprünglichen Attapulgit aufwies. Parathion war an allen vorerhitzten Tonen bei einer Temperatur von 25°C über 190 Tage stabil. Die Reaktion von Parathion an vorerhitzten Tonen wurde bei 110°C untersucht. Es zeigte sich, daß die Hydrolyse von Parathion minimal ist. Die wichtigste Reaktion, die bei Ca-Attapulgit festgestellt wurde, war eine Isomerisierung, während an einem Organo-Ton keine Isomerisierung beobachtet wurde. Es wird ein Mechanismus für die Isomerisierungsreaktion vorgeschlagen, der eine Deformation des Phosphatrestes des Pestizides dutch den Sauerstoff des ligandenwassers nach sich zieht, wodurch sich die Anderungen der Konformation ergeben, die für die Isomerisierung notwendig sind. An dem Organo-Ton war eine derartige Konformation nicht möglich, weshalb keine Isomerisierung auftrat. [U.W.]RésuméOn a étudié l’étata de la structure et d’hydration d’argile attapulgite après échauffement à de hautes temperatures, et la stabilité de parathion sur ces argiles. En utilisant la spectroscopie infra-rouge et la microscopie balaynte électronique on a trouvé que l’eau liée est perdue en deux étapes, à 250° et 450°C la première étape étant réversible. A 650°C la stucture a commencé à se dissoudre, relâchant des quantités significatives de Mg, et un amoindrissement de la porosité de l’aggrégat a été remarqué. A 850°C une phase amorphe a été formée, ressemblant peu à l’attapulgite d’origine. Le parathion êtait stable sur toutes les argiles pré-échauffées lorsqu’elles étalent gardées à 25° pendant 190 jours. Les réactions de parathion sur les argiles pré-échauffées ont été étudites à 110°. On a trouvé que l’hydrolise du parathion était minime. L’isomérisation était la réaction principale se passant sur l’attapulgite-Ca, alors que sur l’argile organique, aucune isomérisation n’a été observée. On propose un mécanisme pour la réaction d’isomérisation, mécanisme qui comprend la distortion de la moitié phosphate du pesticide par l’oxygène de l’eau liante, résultant en les changements conformationnels nácessaires pour que l’isomérsation se passe. Sur les argiles organiques, une telle conformation n’était pus possible; par conséquent, aucune isomérisation ne s’est passée. [D.J.]

Immobilized microorganisms especially bacteria are most used rather than free cells to be protected from the environmental conditions when being used for the bioremediation of environmental pollutants. Herein, two marine’s bacterial isolates were tested for their ability to decompose crude oil. The optimum conditions for effective bacterial degradation e.g., pH, temperature, and inoculum size were investigated. PVA-alginate-clay composite hydrogel beads with different types of incorporated mineral clays were prepared and tested as bacterial carrier for potential bioremediation. Results showed that... attapulgite clay-containing beads recorded maximum degradation% as 78.8 and 75% for both bacterial isolates, when added to immobilization matrices and these percentages could be enhanced under optimal conditions. 

Attapulgite (ATP) is a natural hydrophilic clay mineral known for its reactive -OH groups on the surface and having a layer chain like structure with exchangeable cations in its framework channel. It was reported by Zhu et al. [18] that modified hydrophobic ATP through cation exchange showed high absorption capacity and selectivity to organic solvents and oils owing to its mesoporous structure and hydrophobic treatment which allow it to be effectively applied for crude oil biodegradation issues. ...

A composite proton exchange membrane chitosan (CS)/attapulgite (ATP) was prepared with the organic–inorganic compounding of ATP and CS. The composite membranes were characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The mechanical properties, thermal stability, water uptake, and proton conductivity of the composite membranes were fully investigated. The composite membranes exhibited an enhanced mechanical property, dimensional and thermal stability compared to CS membrane, owing to the interface interaction between ATP and CS. The maximum tensile strength of 53.1 MPa and decomposition temperature of 223.4°C was obtained, respectively. More importantly, the proton conductivity of the composite membrane is also enhanced, the composite membrane with 4 wt% ATP content (CS/ATP‐4) exhibited the highest proton conductivity of 26.2 mS cm−1 at 80°C with 100% relative humidity, which is 25.1% higher than pure CS membrane. These results may explore a simple and green strategy to prepare CS‐based PEMs, which have a great potential in the application of proton exchange membrane fuel cells.

Pollution from heavy-metal ions has become a major challenge to the global fight against environmental pollution. Given the availability of various low-cost and environmentally friendly adsorbents, adsorption has become the most efficient technology for the removal of heavy metals from water. In this study, attapulgite (ATP) was directly functionalized by coupling with an aminosilane agent. Analysis showed this maneuver provided a suitable adsorbent for the removal of lead ion (Pb2+) from an aqueous solution. The effects of several parameters including solution pH, contacting time, adsorbent dosage, and initial Pb2+ ion concentration were investigated. Batch sorption results showed that the adsorption process was rapid and over 98% of Pb2+ was removed within 30 min at the optimal pH 4.0. The maximum adsorption capacity at 25°C, calculated by the Langmuir isotherm, was 82.17, 78.80, 61.13, and 28.56 mg/g for γ-divinyltriaminepropyl-methyldimethoxylsilane-grafted attapulgite (KH-103-ATP), γ-aminopropyl-methyldiethoxysilane-grafted attapulgite (KH-912-ATP), N-(β-aminoethyl-γ-aminopropyl)-methyl-dimethoxysilane-grafted attapulgite (KH-602-ATP), and ATP, respectively. Moreover, molecular dynamics simulations of adsorption behaviors of heavy-metal ions at attapulgite surfaces (010) modified by aminosilane agents were carried out. Both the PMF value and diffusion coefficient of metal ions suggest that KH-103-ATP owns the highest rate constant and capacity compared with the other two. And the analysis of free energy and results of XPS characterization revealed that Pb2+ formed covalent bonds with the nitrogen atom of aminosilane agents.

FULLER’S earth is a clay which has the property of decolorizing oils. Its name was derived from the earliest application in the removal of grease from woolen cloth. More than 45% of the total tonnage of fuller’s earth in the United States comes from the southeastern states, more than from any other section of the country (47). Thenatural activity of fuller's earth is, in contrast to sub-bentonitic clays (montmorillonite), not substan-tially enhanced by treatment with chemicals, such as acids (42). Large deposits of fuller’s earth are found in Decatur County, Ga., and Gadsden County, Fla., near Attapulgus, Ga. It is with this Attapulgus clay that this paper is exclusively concerned. Industrial applications of Attapulgus clay are numerous and have often been described (36). An outstanding use is the decolorizing, deodorizing, dehydrating, and neutralizing of vegetable and mineral oils and waxes which can be accomplished either by con-tacting the oil with fine mesh clay or by percolating the oil in liq-uid phase through a bed of the granular adsorbent (13, 14, 20-22, 41, 43, 43, 48). The spent clay can be regenerated by burning off carbonaceous deposits and hence can be used through a large number of cycles. Fuller’s earth is used in the reclamation of used lubricating, turbine, and transformer oils (23). Georgia-Florida fuller’s earth also finds use in the petroleum industry as a catalyst or catalyst support (4), in the treating of gasoline by the Gray process (46), and in the desulfurization (2, 15), polymerization (18), depolymerization (8, 9), and cracking of hydrocarbons (15). In the sugar industry, Attapulgus clay can be used for pH adjustments of sugar liquors (30). Large amounts of the clay are used as an absorbent floor cleaner to remove oil and grease. The earth will take up as much as 70 to 80% by weight of oil and will

Infrared absorption spectra show important changes in the positions and form of the absorption bands of a film of attapulgite after it has been pumped out. An attempt to differentiate among some of the multiple frequencies due to OH groups is based on the information obtained from dehydration and deuteration experiments. The 1198 cm−1 shoulder, characteristic of attapulgite, is assigned to a Si-O vibration. When attapulgite is refluxed with 5N HCl for 5 hr the octahedral layer is dissolved. The acid attack causes the disappearance of the Si-O-Si absorption bands from attapulgite giving rise to a characteristic vibration at 1090 cm−1, as well as another absorption at 960 cm−1. The latter indicates the presence of silanol groups.

It has been demonstrated that ferric iron is the principal source of the oxidizing action of the surface of attapulgite clay. The extent of oxidizing action in a given time (the oxidizing power) has been determined as a function of the temperature of calcination of the clay in the range 100–900°C.

The oxidizing power was measured with TiCl3 in aqueous acid medium by direct titration of the clay in situ and by titration of extracts of the clay. The dissolution of the metallic cations of the clay was also studied in the same medium. The results have been correlated with structural changes caused by the calcination of attapulgite.

To improve fertilizer use efficiency and minimize its negative impact on environment, a slow-release nitrogen and boron fertilizer with water-retention was prepared. Wheat straw was used as skeletal material in copolymerization on which acrylic acid monomer can be grafted to form superabsorbent composite. Urea and borax were introduced to provide nitrogen (N) and boron (B) nutrients, respectively. The product possessed a core/shell structure. Its core was urea in attapulgite and alginate matrix, and the shell was chemically modified wheat straw-g-poly(acrylic acid)/attapulgite (CMWS-g-PAA/APT) superabsorbent composite containing urea and borax. The effects of the amount of cross-linker, initiator, chemically modified wheat straw and attapulgite on water absorbency were investigated and optimized. The water absorbency of superabsorbent synthesized under optimal conditions was 186 g g−1 in tap water. Ammonia-selective electrode and inductively coupled plasma results showed that the contents of the nitrogen and boron of the product were 23.3% and 0.65%, respectively. The water retention capacity and the slow-release behavior of N and B of the product were investigated. The results showed that the product with slow-release and water-retention capacity, being economical, nontoxic in soil and environment-friendly, could be found good application in agriculture and horticultural.

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