Fuller's Earth Research Articles

Experimental improvement of preparation of acrylic acid-modified middle deacetylated chitosan and its application in absorbing paraquat

Chitosan with 45% deacetylation (CS45) grafted poly (acrylic acid) (CS45-g-PAA) was synthesized and characterized as an adsorbent of paraquat. CS45-g-PAA copolymers were prepared using H2O2(aq) as an initiator and NH4OH(aq) as a promoter. The highest grafting percentage of 44.2% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 52.6% was calculated for the central composite design (CCD). Experimental results based on the reaction conditions that were predicted from the CCD are consistent with theoretical calculations. The grafted copolymer was characterized by FTIR, BET, and SEM. A representative CS45-g-PAA copolymer was hydrolyzed to a salt type (CS45-g-PANa) and used in the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of CS45-g-PANa is 396.7 mg/g-adsorbent. This value clearly exceeds that of Fuller's earth and the activated carbon which is the most commonly used binding agent for paraquat. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Cocos sahnii Kaul: A Cocos nucifera L.-like fruit from the Early Eocene rainforest of Rajasthan, western India

Cocos sahnii Kaul, a fossil palm fruit, is validated and described from the Fuller's earth deposits of Kapurdi village of Rajasthan considered as Early Eocene in age. The fossil best resembles the genus Cocos, particularly Cocos nucifera L., which is now a common coastal element thriving in highly moist conditions. The recovery of this coconut-like fruit, along with earlier described evergreen taxa from the same formation, suggests the existence of typical tropical, warm and humid coastal conditions during the depositional period. The present arid to semi-arid climatic conditions occurring in Rajasthan indicate drastic climate change in the region during the Cenozoic. The possible time for the onset of aridity in the region which caused the total eradication of semi-evergreen to evergreen forests is discussed, as well as the palaeobiogeography of coconuts.

Preparation of methacrylic acid‐grafted chitin using cerium (IV) ion and its application in adsorbing paraquat

AbstractChitin‐grafted‐poly(methacrylic acid) (chi‐g‐PMAA) was synthesized and characterized as an adsorbent of paraquat. Chi‐g‐PMAA copolymers were prepared using various concentrations of ammonium cerium(IV) nitrate (Ce+4) to determine the optimal concentration of Ce+4. Grafting was verified by differential scanning calorimeter thermograms, FTIR, and solid‐state 13C‐NMR spectra. A representative chi‐g‐PMAA copolymer was neutralized to a sodium salt (chi‐g‐PMANa) and used to adsorb paraquat. The adsorption equilibrium data are strongly related to both the Langmuir and the Freundlich isotherms. The maximal adsorption capacity is 147.0 mg/g‐adsorbent. This value exceeds those of Fuller's earth and activated carbon, which are the most common binding agents that are currently used for paraquat. The results suggest that chi‐g‐PMANa has potential as a paraquat adsorbent. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Assessment of antidote stocks in hospitals of the Italian region Emilia Romagna

BackgroundThe Department of Pharmacy of the University Hospital of Ferrara (AOUFE) has been appointed Regional Centre of Reference for the supply of some antidotes by the Region Emilia Romagna (RER)....

Medical management of paraquat ingestion

Poisoning by paraquat herbicide is a major medical problem in parts of Asia while sporadic cases occur elsewhere. The very high case fatality of paraquat is due to inherent toxicity and lack of effective treatments. We conducted a systematic search for human studies that report toxicokinetics, mechanisms, clinical features, prognosis and treatment. Paraquat is rapidly but incompletely absorbed and then largely eliminated unchanged in urine within 12-24 h. Clinical features are largely due to intracellular effects. Paraquat generates reactive oxygen species which cause cellular damage via lipid peroxidation, activation of NF-κB, mitochondrial damage and apoptosis in many organs. Kinetics of distribution into these target tissues can be described by a two-compartment model. Paraquat is actively taken up against a concentration gradient into lung tissue leading to pneumonitis and lung fibrosis. Paraquat also causes renal and liver injury. Plasma paraquat concentrations, urine and plasma dithionite tests and clinical features provide a good guide to prognosis. Activated charcoal and Fuller's earth are routinely given to minimize further absorption. Gastric lavage should not be performed. Elimination methods such as haemodialysis and haemoperfusion are unlikely to change the clinical course. Immunosuppression with dexamethasone, cyclophosphamide and methylprednisolone is widely practised, but evidence for efficacy is very weak. Antioxidants such as acetylcysteine and salicylate might be beneficial through free radical scavenging, anti-inflammatory and NF-κB inhibitory actions. However, there are no published human trials. The case fatality is very high in all centres despite large variations in treatment.

The gassing tendency of various insulating fluids under electrical discharge

Since gas evolvement deteriorates the dielectrical properties of insulating fluid, its ability to resist decomposition under electrical discharge is of paramount importance for the safety of power transformers under operating conditions. In this paper, a series of experiments have been performed under electrical discharge according to ASTM D6180. Various insulating fluids were considered. The samples include minerals oils, synthetic and natural esters, and silicone fluid. The results indicate that the gassing tendency of natural esters is much lower than their counterparts. No significant differences between synthetic esters and silicone fluid were observed. Severely hydrotreated and hydrocracked oils indicate a higher gassing tendency. It is also shown that service-aged oil gassing tendency decreases with reclamation passes. The reclamation of service aged oil by three commercially available Fuller's Earth (FE) showed a declined gassing tendency when FE helped reducing the DDF and turbidity. In addition, the theoretical premises that, oil born decay products contribute to the oil gassing, is experimentally confirmed under laboratory conditions. Extended stability test (3 times longer than the standard specification) also provide convincing evidences that each brand of mineral insulating oil might contain a limited amount of unstable hydrocarbons and volatile compounds. This finding indicates that when in service conditions these are gradually decomposed, the gassing tendency should go down.

Evaluation of peanut hulls as an alternative to bleaching clays

Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller’s earth (FE) and PNH and O-passive (OP) and examined. The oxidative stability of oils was determined. Results for the investigated commercial bleaching clays revealed: TN > FE > F > TF > OP. Highest reduction in PV and PL, and highest bleachability were achieved for soybean oil bleached with 2% PNH carbonized at 500°C for 30 min (PNH”). Mixtures of PNH” with the three chosen bleaching clays indicated that 1PNH”: 2TN gave the highest bleachability. CSO was miscella bleached in hexane using PNH” and resulted in an appreciable improvement in all oil characteristics, especially in bleachability. Oxidative stability of oils was in the following order: TN > control > FE > PNH” with Induction period values of 23,1 > 6,43 > 5,73 > 2,85 h, respectively.

Studies on transport of vapor and solute molecules through polyvinyl alcohol‐based clay containing nanocomposites

AbstractThe present study focuses on fabricating of polymer–clay nanocomposites by in situ polymerization method and investigating their permeability behavior toward vapor and liquid molecules, thus, to evaluating barrier properties of the nanocomposites. For this purpose, acrylonitrile (AN) monomer was grafted on to poly(vinyl alcohol) (PVA) chains after the addition of very low amount of fuller's earth (clay) into polymer matrix using a suitable initiator, such as potassium persulphate (KPS), and crosslinker N‐N′ methylene bisacrylamide (MBA). The prepared nanomaterials were characterized by Fourier‐Transformation infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WXRD) techniques. The morphological features of designed materials were studied by scanning electron microscopy. The graft materials impregnated with fuller's earth were examined for their permeability behavior by observing the permeation of solute and vapor molecules from aqueous dye solution and volatile organic solvent, respectively. The composition of the nanocomposites and the amount of fuller's earth content were found to affect the passage of solute and vapor molecules across the nanocomposite membrane. The permeation capacity was quantified by evaluating permeability parameters. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Simple Techniques to Increase the Production Yield and Enhance the Quality of Organic Rice Bran Oils

This study develops simple techniques for increasing production yield and refining of crude RBO (CRBO). It was found that pre-heating of rice bran by hot air oven to reach 60°C before being extracted by screw press machine increased the yield from 4.8 to 8.3%w/w. This paper suggested three simple steps for refining of organic CRBO: (1) filtering using filter papers (2) sedimentation by adding 4%w/v fuller's earth and (3) bleaching by running through a packed column of activated carbon. These steps significantly enhanced the qualities of RBO when compared to CRBO before treatment. It was found that the lightness of oil as indicated by color value (L*) increased from 22.8 to 28.7, gum and wax decreased from 3.6 to 1.3%w/w. However, the simple refining method had no effect on peroxide value and free fatty acid content. Moreover, it slightly induced the loss of oryzanol content from 2.8 to 2.2%w/w.

Reconstruction of Jurassic (Bathonian) palaeosalinity using stable isotopes and faunal associations

Abstract: The Bathonian is an interval from which salinity-controlled benthic faunas are particularly well known. This study examines Late Bathonian faunas from Dorset, UK, from the Wattonensis Beds (Fuller's Earth), of known marine origin, the overlying Elongata Beds, and the Boueti Bed marking the base of the Forest Marble. δ 18 O values of belemnites ( Belemnopsis ) from the Wattonensis Beds range from −1.4 to −0.7‰ and carbon isotope values range from −2.3 to −0.5‰ VPDB. Isotope values of well-preserved Rhynchonella from the Wattonensis Beds range from −2.4 to −1.3‰ for oxygen and −1.1 to 0.6‰ VPDB for carbon. The δ 18 O data suggest high palaeotemperatures (possibly up to 28 °C). A similar spread of data is derived from brachiopods ( Goniorhynchia boueti ) from the Boueti Bed. Given the marine origin of the Wattonensis Beds and overlap of data, the reduced faunal diversity of the Boueti Bed is considered unlikely to be the result of reduced salinity. Brachiopods therefore should not be regarded more sceptically as evidence for fully marine conditions, as has been suggested. The oysters ( Praeexogyra hebridica elongata ) and brachiopods ( Rhynchonella ) from the Elongata Beds have isotope values that also imply fully marine conditions and are interpreted as being indicative of slightly cooler conditions.

Cutaneous challenge with chemical warfare agents in the SKH-1 hairless mouse (II): Effects of some currently used skin decontaminants (RSDL and Fuller’s earth) against liquid sulphur mustard and VX exposure

Using the hairless mouse screening model presented in the companion paper(1) the aim of this study was to assess two skin decontaminating systems: Fuller's earth (FE) and Reactive Skin Decontamination Lotion (RSDL) against two extremely toxic chemical warfare agents that represent a special percutaneous hazard, sulphur mustard (SM) and O-ethyl-S-(2[di-isopropylamino]ethyl)methyl-phosphonothioate (VX). Five minutes after being exposed on the back to either 2 µL of neat sulphur mustard or 50 µg.kg(-1) of diluted VX, mice were decontaminated. Both systems were able to reduce blisters 3 days after SM exposure. However, RSDL was found to be more efficient than FE in reducing the necrosis of the epidermis and erosion. In the case of VX exposure, RSDL, whatever the ratio of decontaminant to toxicant used (RSDL 10, 20, 50), was not able to sufficiently prevent the inhibition of plasma cholinesterases taken as a surrogate marker of exposure and toxicity. Only FE reduced significantly the ChE inhibition. Some of these observations are different from our previous results obtained in domestic swine and these changes are thus discussed in the perspective of using SKH-1 hairless mice for the initial in vivo screening of decontaminants.

Polyvinyl alcohol fuller's earth clay nanocomposite films

AbstractNano fuller's earth was prepared by milling and subsequent sonication of clay. The polyvinyl alcohol (PVA) and PVA ‐Nano clay composite films were prepared by solution casting method. The films were characterized for their structural, mechanical, and thermal properties using electron microscopes (SEM, TEM), Tensile Tester, dynamic mechanical analyzer (DMA), thermo gravimetric analyzer (TGA), and Raman spectroscopy. The nanocomposite films showed improvement in mechanical properties, viscoelastic behavior as well as resistance towards thermal degradation. Uniform distribution of clay due to intimate interaction between clay and polymer appears to be the cause for improved properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption

Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5 mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state 13C NMR spectroscopy.

Lipase immobilization on O-propargyl and O-pentynyl dextrans and its application for the synthesis of click beetle pheromones

Lipase of Rhizopus arrhizus was immobilized on O-propargyl dextran (PgD) and O-pentynyl dextran (PyD). Compared with Lewatit VP OC 1600 cation ion exchange resin, wood shaves, fuller earth, silica and alumina, PgD with degree of substitution (DS) of 0.68 and a surface of 10 m 2/g was found to be the most effective immobilization support and an excellent biocatalyst for esterification reactions in organic solvents as the synthesis of click beetle pheromone geranyl octanoate. PyD (DS 0.44) with a surface of 3.3 m 2/g was of similar high efficiency. For the enzymatic esterification the optimum concentration of geraniol and octanoic acid was 0.4 mol L −1 each. The biocatalyst worked the best in hexane at a moisture level of 0.02%. The enzyme could be repeatedly used and conversion dropped from 80% to 70% after four cycles, while reaction rate even increased when repeatedly employed.

EFFECTS OF REFINING ON QUALITY ATTRIBUTES OF AFRICAN PEAR (DACRYODES EDULIS) OIL

ABSTRACT Oil extracted with hexane from dried African pear (Dacryodes edulis) mesocarp was degummed with 1 or 5% NaOH or H3PO4, and bleached with fuller's earth. Degumming and bleaching produced lighter-colored oils with lower specific gravity and free fatty acid content. However, degummed oils had higher peroxide value (PV) (16.50 mEq/kg for 1% H3PO4-degummed oils) than crude oil (8.00 mEq/kg). Bleaching drastically reduced the PV of degummed oils, with oil degummed with 1% NaOH having the lowest value after bleaching (1.50 mEq/kg). PRACTICAL APPLICATIONS The main thrust of the study is industrial utilization and value-added processing of African pear, a lesser-known African crop of considerable horticultural, nutritional and environmental significance, with a view to promoting its cultivation, reducing postharvest fruit losses and enhancing the income of small-scale farmers that cultivate the crop. Practical applications include establishment of small-scale industries for extracting and refining vegetable oil from oil-rich African pear fruits.

Comparison of selected skin decontaminant products and regimens against VX in domestic swine

An anesthetized domestic swine model was used to compare the efficacy and cross-contamination potential of selected skin decontaminant products and regimens against the chemical warfare agent, VX. Animals topically exposed to 2x, 3x or 5x LD(50) VX showed typical signs of organophosphate nerve agent poisoning, including miosis, salivation, mastication, dysrhythmias, and respiratory distress prior to death. Animals were exposed to 5x LD(50) VX and then decontaminated 45 min later with the reactive skin decontamination lotion (RSDL), Fuller's earth (FE), 0.5% hypochlorite, or soapy water. Survival was 100% when the reactive skin decontamination lotion or FE was utilized, although 50% of Fuller's earth-decontaminated animals exhibited serious signs of VX poisoning. Decontamination of VX-treated animals with 0.5% hypochlorite was less effective but also increased survival. Soapy water was ineffective in preventing lethality. Blood cholinesterase levels were not predictive of clinical outcome in decontaminated animals. The potential of "decontaminated" VX in open wounds to cause poisoning was assessed by vigorously mixing 5x LD(50) VX with the test decontaminants for 5 min and then placing the mixture onto a full-thickness skin wound. Soapy water was ineffective in preventing lethality. Although treatment with dry Fuller's earth prevented death and all signs of organophosphate poisoning, a significant proportion of treated animals decontaminated with Fuller's earth in aqueous suspension exhibited serious signs of organophosphate poisoning, suggesting that live agent may be desorbed from Fuller's earth when it is exposed to a liquid environment. Animals treated with reactive skin decontamination lotion or 0.5% hypochlorite-VX mixtures showed no signs of organophosphate poisoning during the 6- h test period.

Fetal poisoning after maternal paraquat ingestion during third trimester of pregnancy: Case report and literature review

Paraquat remains one of the common substances involved in intentional ingestions in Thailand. However, data on outcomes of paraquat ingestion during pregnancy is rarely available and the management is controversial. A 17-year-old female in 36 weeks of gestation attempted suicide by ingesting 1/2 a glass of Gramozonetrade mark (paraquat 27.6 % w/v) 5 hours prior to arrival to the hospital. Gastric aspiration and lavage was performed and she was given 50 g of activated charcoal and 150 g of Fuller's Earth suspension. A male infant, weighing 2,390 g with an Apgar score of 71 1010, was delivered via emergency caesarean section 7 hours after ingestion. Due to presence of paraquat in the gastric lavage fluid, the mother was placed on dexamethasone/cyclophosphamide therapy. She developed mild renal insufficiency 63 hours after the ingestion. The infant developed tachypnea immediately after birth that self-resolved. The infant developed tachypnea again on day 6 of life. A chest x-ray revealed right lower lobe infiltration that progressed to diffuse interstitial pattern; subsequent chest x-rays showed evidence of fibrosis. Both mother and infant survived and the infant was discharged and sent home with oxygen 0.5 LPM. Upon follow up at 10 months of age, he still had evidence of chronic lung disease clinically and on chest x-ray. Paraquat ingestion during the third trimester of pregnancy usually carries a very poor prognosis. Review of reported literature suggests that this case report represents only the second survival of mother and child.

Electrically conducting polypyrrole–fuller's earth nanocomposites: Their preparation and characterisation

Cu(II)-exchanged fuller's earth was prepared by ion-exchanging Ca 2+ ions which are present within the interlayer of fuller's earth with Cu(II)ions by the solution-phase ion-exchange process. Pyrrole was introduced into Cu(II)-exchanged fuller's earth to spontaneously polymerize to within the interlayer to result in a nanocomposite of Cu(I)–polypyrrole–fuller's earth where both Cu(I) and polypyrrole occupy within the interlayer spaces of fuller's earth. The nanomaterial [Cu(I)–PPY–FE] has been fully characterized with X-ray diffraction studies, FTIR spectroscopy, DC polarisation test with both blocking stainless steel and non-blocking copper electrodes. The material is found to be a mixed conductor whose ionic mobility is 1.5 times faster than electronic mobility. DC polarisation studies also clearly revealed that the mobile ionic species in this material to be cuprous ions. AC impedance studies have been carried out with blocking stainless steel electrodes at different applied potentials. The necessary theoretical background to explain AC impedance results is also provided and the results obtained agree very well with the corresponding data obtained by other mutually independent methods. The electronic conductivities are around 3.0 × 10 −4 S cm −1 and the ionic conductivities are around 9.0 × 10 −3 S cm −1. The material may find applications in semi-fuel cells such as air–metal batteries.

Effects of Clay Mineral Application on Soil Moisture Status, Physiological Traits and Yield of Rainfed Tomato under Semi-Arid Alfisols

The effects of application of farm yard manure (FYM) and clay mineral (CM) on soil and plant characteristics like soil moisture at field capacity, permanent wilting point, leaf area, leaf nitrogen, relative water content, yield of tomato were examined based on field experiments conducted in a semi-arid alfisol at Hyderabad during 1998 -99 and 1999-2000. Two levels of FYM and three levels of CM (fullers earth) were applied in the filed. The Analysis of Variance indicated that application of 16 t/ha of CM together with 10 t/ha of FYM retained a significantly higher soil moisture as measured by pressure outflow and gravimetric methods. The per cent survival, leaf area and relative water content was also significantly higher. On the other hand, application of 8 t/ha of CM together with 10 t/ha of FYM helped to achieve maximum leaf N, higher marketable yield, fruit firmness, total soluble solids, total soluble solids-acidity ratio in tomato under semi-arid alfisols.

Adsorption, kinetics and equilibrium studies on removal of Cr(VI) from aqueous solutions using different low-cost adsorbents

Abstract The removal of Cr(VI) from aqueous solution by batch adsorption technique using different low-cost adsorbents was investigated. Adsorbents such as clarified sludge—a steel industry waste material, rice husk ash, activated alumina, fuller's earth, fly ash, saw dust and neem bark were used to determine the adsorption efficiency. The influence of pH, adsorbent type and concentration, initial Cr(VI) concentration and contact time on the selectivity and sensitivity of the removal process were investigated. Adsorption process was found to be highly pH dependent. The optimum pH range for adsorption of Cr(VI) was found to be between 2 and 3. Kinetics studies were performed to understand the mechanistic steps of the adsorption process and the rate kinetics for the adsorption of Cr(VI) was best fitted with the pseudo-2nd-order kinetic model. Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated. The thermodynamic equilibrium constant and the Gibbs free energy were determined for each system. The adsorption capacity (qmax) calculated from Langmuir isotherm and the Gibbs free energy (ΔGo) value obtained for the different adsorbents showed that clarified sludge was the most effective among the selected adsorbents for the removal of Cr(VI) from aqueous solution. The adsorption efficiencies of rice husk ash and activated alumina were also equally comparable with that of clarified sludge.