Varied forms of palygorskite and sepiolite from different geologic systems

Both palygorskite and sepiolite occur as sheets in tension fracture zones, fault zones, and caves in rock strata, as well as forming strata in alluvial terraces. The sheets of fibrous clays were commonly named mountain leather or mountain cork. The fibrous clays occur in geologic host rock systems of Paleozoic and Mesozoic ages as well as Quaternary age. The analyzed palygorskites represent a continuous series with Al₂O₃ contents ranging from 16.3 wt.% to 4.8 wt.% and (110) XRD peaks from 10.30 Å to 10.57 Å. When less than about 8 wt.% Al₂O₃ is present secondary NIR Mg related OH bands may be observed along with the palygorskite spectra. The analyzed sepiolites have (110) XRD d-values ranging from 12.03 Å to 12.26 Å. The latter is an Fe-sepiolite (xylotile). DTA analyses show that the palygorskite exotherm temperatures form a linear function with the Al₂O₃ contents, from 1045 °C at 16.3 wt.% to 880 °C at 4.8 wt.% Al₂O₃. The fibrous clays can readily adsorb considerable amounts of metals, such as Pb, As, and Cd. The amounts held can be used for determining whether the clays are classified as hazardous materials, on the basis of U.S. EPA and California State standards.     

Clay mineral-supported gold nanoparticles

Supported gold nanoparticles were prepared on clay minerals from the smectite and sepiolite–palygorskite groups (particularly montmorillonite and sepiolite) by cation adsorption from the cationic gold precursor Au(en)₂Cl₃ (en = ethylenediamine). Thermal gravimetric analysis, X-ray diffraction, transmission electron microscopy (TEM), high resolution TEM (HRTEM) and energy dispersive X-ray spectroscopy (EDS) were used to characterize these potential gold catalysts. The results show that the mean diameters of gold particles supported both on sepiolite and on montmorillonite are below 5 nm after calcination at 350–450 °C when the gold loading is lower than 2 wt.%. An increase of the amount of the gold precursor results in agglomeration of gold nanoparticles. An organosilane functionalized sepiolite was also used as support to obtain highly dispersed gold nanoparticles on the modified mineral surfaces, with narrow size distribution and an average size of 2.7 nm.     

Preparation of TiO2-pillared montmorillonite as photocatalyst Part I. Microwave calcination, characterisation, and adsorption of a textile azo dye

Two photocatalysts based on TiO₂-pillared intercalated montmorillonite have been prepared by microwave for 10 min at 700 W or by furnace heating at 673 K. Montmorillonite pillaring with TiO₂ increased the basal spacing to 14.7 Å (conventional heating) and 17.6 Å (microwave heating). XRD patterns of both materials showed the presence of 100% anatase with a slightly higher rate of crystallinity obtained through microwave calcination than by conventional heating at 673 K. The BET specific surface area of the microwave prepared photocatalyst (151 m² g^− 1) was 3 fold higher than those of the Degussa TiO₂ P25. At pH = 5.8, the maximum adsorption capacity of Solophenyl red 3BL (a textile azo dye) on the TiO₂-pillared montmorillonite calcined by microwave was 185 mg g^− 1, whereas it was 1.4 and 3 fold lower on the TiO₂-pillared montmorillonite calcined at 673 K, and on the Degussa TiO₂ P25 respectively. The influence of pH on the adsorption of the dye depended on the pH_ZPC of the pillared montmorillonites.     

Effect of the crystallinity of kaolinite precursors on the properties of mesoporous silicas

Mesoporous silicas (MesoPSs) were hydrothermally synthesized from calcined and selectively acid-leached kaolinites with a range of crystallinity, using cetyltrimethyl ammonium bromide (CTABr), to investigate the effect of the kaolinite crystallinity on the porous properties of the resulting MesoPSs. Four kaolinites were used, with Hinckley indices ranging from 0.51 to 1.20 and (001) crystallite sizes ranging from 20 to 37 nm. After calcination at 600 °C for 24 h they were selectively leached with 2.5 M H₂SO₄ at 90 °C for 2 h to prepare microporous silica (MicroPSs). The Si/Al ratios of these MicroPSs varied from 21 to 82 and their specific surface areas (S_BET) ranged from 169 to 370 m²/g, these parameters tending to increase with decreasing Hinckley index of the kaolinite. MesoPSs were synthesized by reacting the resulting MicroPSs with CTABr in NaOH solution under hydrothermal conditions. The MicroPS was mixed with CTABr, NaOH and water in the molar ratio (MicroPS):CTABr:NaOH:H₂O = 1:0.1:0.3:150. The synthesis was carried out by stirring the suspension at room temperature for 24 h, aging for 24 h, hydrothermal treatment at 110 °C for 24 h and calcination at 560 °C for 6 h to remove the surfactants. The S_BET values of the resulting MesoPSs ranged from 932 to 1240 m²/g, correlating with the S_BET values of the precursor MicroPS and the crystallinity of the kaolinite starting materials.     

Clay minerals and iron oxides-oxyhydroxides as fingerprints of firing effects in a limestone monument

Different Portuguese limestones-Encarnadão, Amarelo de Negrais, Lioz and Gresoso-have been widely used as building materials and ornamental stones in the architecture of Lisbon (Portugal) area.The aim of the study of those materials was focused on fire-induced stone damage, mainly on identifying the thermal transformations of clay minerals and iron oxides-oxyhydroxides. Taking into account an applied component to the cultural heritage, a special attention was given to one of the most ancient Portuguese monuments — Lisbon Cathedral, specifically its cloister that was severely damaged by a fire that occurred right after the 1755 earthquake.A set of samples collected from outcrops were studied and subjected to artificial heating. The results were compared with those obtained from samples collected in the monument. XRD, SEM-EDS and ⁵⁷Fe Mössbauer spectroscopy were used. The < 2 µm fraction varies significantly between unheated (outcrop samples) and artificially heated samples, particularly in relation to iron oxides-oxyhydroxides. Kaolinite is the dominant clay mineral, followed by illite and smectite. Goethite is the iron oxyhydroxide characteristic of all studied lithotypes both in unheated samples and samples artificially heated to 250 °C. Encarnadão is the exception presenting hematite in those conditions. As firing temperature increases (300 °C–600 °C) disordered hematite appears at the expense of goethite, and smectite is no longer detected. Mössbauer spectra further reveal that Fe²⁺ in silicate minerals is fully oxidized at 600 °C but remains in the carbonate structure up to this temperature. The SEM-EDS analyses show that 2:1 clay minerals have Si and Al as main cations and minor amounts of K and Fe. It also shows that all the clay minerals and Fe-rich particles are always associated to the limestone porosity.. The present results show that the clay minerals, namely illite–smectite mixed-layer and smectite, can be used as indicators of stone provenance used in Lisbon Cathedral Cloister as well as fingerprints of the temperature achieved during the fire of Lisbon Cathedral that most likely was not higher than 350 °C.     

Memory effect-enhanced catalytic ozonation of aqueous phenol and oxalic acid over supported Cu catalysts derived from hydrotalcite

Mg/Al supported metal (Fe, Co, Ni and Cu) oxide catalysts were prepared by co-precipitation of hydrotalcite-like clay materials as precursors, calcined, and used for the ozonation reaction of phenol and oxalic acid. The reaction was carried out using the catalyst and aqueous solution of phenol or oxalic acid in an O₃/O₂ mixed gas-flow at 20 °C. In the ozonation of phenol, the combination of ozone and supported metal oxide catalysts was effective for the removal of total organic carbon (TOC). Also in the ozonation of oxalic acid as the main TOC component, Cu/Mg/Al catalysts showed the highest activity, followed by Ni/Mg/Al catalyst, while both Fe/Mg/Al and Co/Mg/Al catalysts were not active. Leaching of Cu and Ni, probably due to the chelation of metals by oxalic acid, was significantly observed at the beginning of the reaction. However the metal leaching disappeared at the end of the reaction possibly due to the entire consumption of oxalic acid during the reaction. The best result of oxalic acid mineralization was observed over Cu/Mg/Al catalyst calcined at 600 °C, on which least leaching of the metal was detected. Moreover, a “memory effect” of hydrotalcite accelerated the mineralization of oxalic acid over the Cu/Mg/Al catalyst; oxalate anions were captured and decomposed in the reconstituted hydrotalcite interlayer space on the surface of the Cu/Mg/Al catalyst, resulting in a remarkable enhancement in the catalytic activity of the ozonation.     

Microstructural evaluation of a clay ceramic incorporated with petroleum waste

In this work an extensive SEM/EDS microstructural investigation associated with technological properties was carried out on kaolinitic clay bodies incorporating different amounts, up to 20 wt.%, of a bentonite-treated petroleum waste. The clay bodies were fired at temperatures from 850 to 1100 °C and then bend tested until rupture. Fracture surface observation revealed the existence of relatively small BaSO₄ particles that do not significantly contribute to the rupture process. By contrast, larger clay matrix embedded particles and voids exert more influence on the ceramic rupture. Since these particles are also normal features in waste-free clay bodies, the incorporation of bentonite-treated petroleum waste cannot be directly related to the rupture process. Exception occurred above 10 wt.% added waste and temperatures higher than 1000 °C, at which the comparatively higher amount of non-plastic quartz particles plays a role in the decrease of strength.     

Synthesis of highly stabilized mesoporous molecular sieves using natural clay as raw material

Mesoporous molecular sieves were hydrothermally synthesized from natural clay and sodium silicate by using cetyl trimethyl ammonium bromide (CTAB) as a template. The samples were characterized by means of XRD, TEM, TPR, FT-IR and N₂ physical adsorption. The results show that well-ordered and highly stabilized mesoporous molecular sieves were obtained by adjusting the proportion of raw materials. The pore structure of the as prepared mesoporous molecular sieves was not damaged after calcination at 850 °C for 3 h or hydrothermal treatment at 100 °C for 10 days. The mesoporous ordering became better after hydrothermal treatment, but the pore shrank and the surface area decreased after thermal treatment. The stability of the as prepared mesoporous molecular sieves depends on the stability of the clay present in mesoporous pore walls. The presence of clay in the walls can be certified by the regular pore channel images as determined by TEM and XRD analyses.     

Thermal activation and alkali dissolution of silicon from illite

TGA, DTA, FTIR, XRD and 29Si MAS NMR were used to investigate the thermal activation of illite. Illite experiences a series of thermal solid-state phase transformations. Dehydroxylation at 400700 °C forms dehydrated illite, which remains the layered framework of illite. From 700 °C to 1093 °C, Si–O tetrahedral framework remains unchanged. When heated above 1093 °C, the layered structure is destroyed and an amorphous silica-rich glass phase is formed. The mullitization occurs when the temperature exceeds 1100 °C.XRD and FTIR studies show that the silica in silica-rich glass phase dissolves in soda liquor, which indicates that silicon can be removed from illite after thermochemical activation (TCA) followed by alkali leaching. The formation of sodium aluminosilicates of Na₉₆Al₉₆Si₉₆O₃₈₄ and 0.95Na₂O · Al₂O₃ · 3.25SiO₂ · 4.79H₂O during alkali leaching may reduce the desilication to a great extent.Desilication tests after TCA show that the suitable activation conditions for illite are 11001150°C and 9060 min. A desilication of 45% was obtained under the conditions for an ore sample bearing about 85% illite, 9% quartz and 5% muscovite.     

Tritium redistribution between water and clay minerals

Hydrogen-isotope exchange between clay minerals and tritiated water was studied with kaolinite, montmorillonite and palygorskite. At all possible positions, tritium accumulated most intensively during the initial stage (10 to 20 days) but further increase of tritium concentration in experimental systems was much less intensive. Interaction of tritiated water with clay minerals decreased in a similar manner. In all samples, the highest amounts of tritium atoms and the maximum accumulation rates (V) were observed in the surface-adsorbed water (V_surf) over the complete study period. The modes of tritium accumulation in the interlayer space (montmorillonite) and in the channels (palygorskite) (V_inter) are quite similar and both types of structures are very suitable for hydrogen-isotope exchange. Availability of well-developed paths for the access of T⁺ ions to structural OH-groups (V_struct) enables intense tritium accumulation at these positions in montmorillonite and palygorskite (V_inter  V_struct). In kaolinite the access of T⁺ ions to structural OH-groups is more difficult, in spite of the considerable number of potential exchange positions in its structure, therefore resulting in lower tritium adsorption in comparison with the other two clay minerals.     

Dissolution kinetics of dehydroxylated nickeliferous goethite from limonitic lateritic nickel ore

The dissolution kinetics in 2 M H₂SO₄ of variously dehydroxylated nickeliferous goethites was investigated for five oxide-type lateritic nickel deposits. Goethite was the main constituent with minor amounts of quartz, talc, kaolinite and Mn oxides. Dissolution of Fe from heated materials followed the Kabai equation. There was a 9–34-fold increase in the Kabai dissolution rate constant (k) for samples heated at 340–400 °C due to both the increased surface area (1.5–2.6 fold) and higher density of structural defects (5–10 fold) in the variously dehydroxylated products. The presence of structural Al and Cr in goethite appears to reduce dissolution rate possibly through the greater M³⁺–OH, O bond strength relative to Fe³⁺, Ni²⁺–OH, O. Nickel showed congruent dissolution with Fe indicating that Ni was uniformly incorporated in the goethite structure. Pre-heating goethite to 600–800 °C for 30 min resulted in incongruent dissolution of Fe and Ni. It is postulated that some Ni is ejected from the neo-formed hematite structure and resides on the crystal surface or in voids. These results may contribute to the development of more efficient procedures for Ni extraction including heap leaching of lateritic nickel ores.     

Characterization of Ce0.9Gd0.1O1.95 powders synthesized by spray drying

Ce_0.9Gd_0.1O_1.95 powders were synthesized by spray drying and successive calcinations. The phase purity, BET surface area, and particle morphology of as-sprayed and calcined powders were characterized. After calcination above 300 °C, the powders were single phase and showed a BET surface area of 68 m²/g when calcined at 300 °C. The conductivity, in air, of sintered pellets was measured by electrochemical impedance spectroscopy (EIS) and it was found to be comparable with literature values. The activation energy for the total conductivity was around 0.83 eV. The powder calcined at lower temperature showed better sinterability and higher total conductivity due to an increased bulk conductivity.     

Characterization of sepiolite as a support of silver catalyst in soot combustion

Turkish sepiolite–zirconium oxide mixtures were applied as a support for the silver catalyst in a soot combustion. Sepiolite–Zr–K–Ag–O catalyst was characterized by XRD, N₂ adsorption, SEM, TPR-H₂ and EGA-MS. The combustion of soot was studied with a thermobalance (TG-DTA). The modification resulted in a partial degradation of the sepiolite structure, however, the morphology was preserved. The adsorption of N₂ of the modified sepiolite is a characteristic for mesoporous materials with a wide distribution of pores. The specific surface area S_BET equals 83 m²/g and the pores volume is 0.23 cm³/g. The basic character of the surface centers of sepiolite is indicated by CO₂ desorption (TPD-MS) at 170 °C and at about 620 °C due to a surface carbonates decomposition. The thermodesorption of oxygen at 650–850 °C indicates the decomposition of AgO_x phases at the surface. The presence of AgO_x phases is also confirmed by TPR-H₂ spectrum (low temperature reduction peak at 130 and 180 °C). The high-temperature reduction at about 570 °C is probably related to Ag–O–M phases on the support.The soot combustion takes place at T₅₀ = 575 °C. Without silver (sepiolite–Zr–K–O) T₅₀ = 560 °C but sepiolite modified with silver (sepiolite–Zr–K–Ag–O) undergoes the same process at T₅₀ = 490 °C.     

Adsorption and binding of the transgenic plant proteins, human serum albumin, β-glucuronidase, and Cry3Bb1, on montmorillonite and kaolinite: Microbial utilization and enzymatic activity of free and clay-bound proteins

Human serum albumin (HSA), β-glucuronidase (GUS), and the Cry3Bb1 protein from Bacillus thuringiensis subsp. kumamotoensis are expressed by genetically-modified plants. Commercial samples of these proteins adsorbed and bound rapidly on the clay minerals, kaolinite (K) and montmorillonite (M). Adsorption increased as the concentration of protein increased and then reached a plateau. The greatest amount of adsorption and binding occurred with the Cry3Bb1 protein, of which there was no desorption: 6.7 ±0.21 μg adsorbed and bound μg^− 1 of M; 2.1 ± 0.39 μg adsorbed and bound μg^− 1 of K. With GUS, 2.2 ± 0.29 μg adsorbed and 1.7 ±0.21 μg bound μg^− 1 of M; 1.5 ± 0.28 μg adsorbed and 1.0 ± 0.03 μg bound μg^− 1 of K. HSA was adsorbed and bound the least: 1.2 ±0.04 μg adsorbed and 0.8 ± 0.05 μg bound μg^− 1 of M; 0.4 ± 0.05 μg adsorbed and 0.4 ± 0.03 μg bound μg^− 1 of K. However, X-ray diffraction analyses indicated that only HSA intercalated M, and none of the proteins intercalated K, a nonswelling clay. When bound, the proteins were not utilized for growth by mixed cultures of soil microorganisms, whereas the cultures readily utilized the free (i.e., not adsorbed or bound) proteins as sources of carbon and energy. The enzymatic activity of GUS was significantly enhanced when bound on the clay minerals. These results indicated that recombinant proteins expressed by transgenic plants could persist and function in soil after release in root exudates and from decaying plant residues as the result of the protection provided against biodegradation by binding on clay minerals.     

DI-B experiment: planning, design and performance of an in situ diffusion experiment in the Opalinus Clay formation

The DI-B experiment is a long-term, natural-scale, in situ diffusion experiment, which is being performed in the Opalinus Clay formation at the Mont Terri Underground Rock Laboratory (URL), in Switzerland, employing nonradioactive tracers. One of the key aspects to be addressed for nuclear waste repository safety assessment purposes is the understanding of the transport mechanisms of the radionuclides contained in the radioactive waste. Consolidated clay formations display very low water hydraulic conductivities, so it is expected that the predominant transport process will be diffusion.The experimental set-up has been designed to withstand the site conditions and for monitoring and recording several physicochemical parameters (pH, conductivity, oxidation–reduction potential), as well as the pressures in the circuit and for the long-distance monitoring of the data acquisition system.The tracer selection has been made based on previous investigations carried out at CIEMAT, including a literature survey, laboratory sorption experiments and hydrogeochemical modeling for determining tracer stability under the physicochemical conditions to be expected in the site. The final selection includes ⁶Li, ⁸⁷Rb, D (as D₂O) and I (as I⁻). Hydrogeochemical modeling confirmed the stability of all the tracers selected. Batch sorption experiments showed that no sorption in the rock occurred in the case of ⁶Li, D and I (conservative tracers), whereas ⁸⁷Rb was 100% sorbed. However, ⁸⁷Rb was chosen because of its analogy with Cs, a relevant radionuclide commonly present in the nuclear spent fuel.Diffusion experiments have been carried out at laboratory scale with Opalinus Clay samples to provide diffusion parameters for modeling purposes. Effective diffusion coefficients, perpendicular and parallel to the bedding planes of the rock, respectively, were (1.68± 0.42)×10⁻¹¹ and (4.02± 0.30)×10⁻¹¹ m²/s for tritium, and (2.70± 0.27)×10⁻¹² and (1.38± 0.49)×10⁻¹¹ m²/s for iodide. Additional through-diffusion experiments (parallel to the bedding) were performed with the nonsorbing tracer ³⁶Cl⁻, in order to check the results obtained for iodide. The effective diffusion coefficient measured for chloride ions was (1.18± 0.27)×10⁻¹¹ m²/s, which is practically equal to the value obtained for iodide.Preliminary diffusion calculations have been carried out using two transport codes: GIMRT and CORE^2D, with conservative and nonconservative tracers, using effective diffusion coefficients (D_e) obtained experimentally in the laboratory (through-diffusion experiments) or selected from the literature. The diffusion profiles obtained from the calculations showed slight variations, which were consistent with the different modeling approaches employed. The predictive modeling results have been used to determine the initial tracer concentration that should be added to the circuit to assure well-defined profiles at the end of the experiment.This long-term in situ diffusion experiment will also provide useful data for the interpretation of previous diffusion experiments performed at the Mont Terri URL.     

Algerian kaolinite used for mullite formation

In the present study, mullite was synthesized through reaction sintering of Algerian kaolinite and high purity alumina. The raw powders were wet ball milled in a planetary ball mill. Powders' morphology and the microstructure of the sintered samples were characterized by means of a scanning electron microscope. An X-ray diffractometer equipped with a heating facility and a differential thermal analyzer were used to follow mullite formation. Cylindrical specimens were produced by uniaxial cold compaction at a pressure of 75 MPa and sintered at different sintering temperatures for different sintering times. The heating rate was 10 °C/min. It was found that Algerian kaolinite was suitable for mullite production through reaction sintering with pure Al₂O₃. Formation of complete mullite occurred at 1550 °C. A relative density of 94% (of the theoretical density) was achieved at a relatively low sintering temperature of 1600 °C and a sintering time of 4 h.     

Facile preparation of Na-free anatase TiO2 film with highly photocatalytic activity on soda-lime glass

Na-free anatase TiO₂ film was prepared on soda-lime glass (SL-glass) from a TiF₄ aqueous solution upon addition of boric acid at 60 °C. It was found that the as-prepared TiO₂ film before calcination showed a higher photocatalytic activity than the calcined sample (500 °C). This could be attributed to the fact that the calcined TiO₂ film contained decent Na⁺ ions, which was diffused from the SL-glass substrate into the TiO₂ film during calcination, resulting in the decrease of photocatalytic activity.     

Bleaching of kaolins and clays by chlorination of iron and titanium

The quality of the clays and over all kaolin is measured in function of iron content, since this element gives an undesirable reddish color to this type of minerals. The use of chlorination for iron and titanium removal from different clay and kaolin minerals, used in Argentinian ceramic industry, has been investigated to establish reaction mechanisms, precautions and optimal conditions to bleach the clays. The method consists of the calcinations of the pellets in a flow of chlorine gas at temperatures between 700 and 950 °C, to remove the iron and the titanium by volatilization of the respective chlorides. Isothermal and non-isothermal chlorination assays were made and the effects of the temperature, reaction time, and carbon content in the sample over the bleach of the minerals and the phase transformations suffered by these minerals during the chlorination step were investigated. The removed amounts of iron and titanium were determined by X-ray fluorescence, the phase transformations were followed by X-ray diffraction and the samples' bleaching was established making an analysis of the space of the color by the spectrophofotometric method CIELAB. Also, a thermodynamic analysis of the system using HSC Chemistry for Windows software was made. The experimental results show that for red clay with high colloidal iron content, the optimum working temperature for the iron quantitative removal, without aluminium loss, is close to 850 °C, in controlled atmosphere free of O₂ and H₂O; lower temperatures require long reaction times. The extraction of titanium is not quantitatively achieved, as that of iron, even for long reaction times, because this element is present in different structures, with the consequent variation of its reactivity. The content of carbon and organic matter in the clays, in the case of the San Luis red clay, is enough for extraction improvement. However, the optimum concentration of carbon can vary depending on the type of clay and the amount of Fe₂O₃ in the mineral. The formation of phases such as α-Al₂O₃, a product of chlorination, increases the piece hardness. The methodology used in this work allows for obtaining a great improvement in the color of the final product of the firing, achieving ceramic materials with notable whiteness, even with red clays.     

Beneficial effects of the use of a nickel membrane reactor for the dry reforming of methane: Comparison with thermodynamic predictions

The development of a nickel composite membrane with acceptable hydrogen permselectivity at high temperature in a membrane reactor for the highly endothermic dry reforming of methane reaction was the purpose of this work. A thin, catalytically inactive nickel layer, deposited by electroless plating on asymmetric porous alumina, behaved simply as a selective hydrogen extractor, shifting the equilibrium in the direction of a higher hydrogen production and methane conversion. The main advantage of such a nickel/ceramic membrane reactor is the elimination or limitation of the side reverse water gas shift reaction. For a Ni/Al₂O₃ catalyst, containing free Ni particles, normally sensitive to coking, the use of the membrane reactor allowed an important reduction of carbon deposition (nanotubes) due to restriction of the Boudouard reaction. For a Ni–Co/Al₂O₃ catalyst, where the metallic nickel phase was stabilized by the alumina, the selective removal of the hydrogen significantly enhanced both methane conversion (+67% at 450 °C, +22% at 500 °C and +18% at 550 °C) and hydrogen production (+42% at 450 °C, +32% at 500 °C and +22% at 550 °C) compared to the results obtained for a packed-bed reactor. The hydrogen selectivity during the catalytic tests at 550 °C, maintained with constant separation factors (7 for H₂/CH₄, 8 for H₂/CO and 10 for H₂/CO₂), higher than Knudsen values, attested to the high thermal stability of the nickel composite membrane.     

微生物絮凝剂用于染料废水脱色及其动力学研究

从活性污泥中筛选出的一株微生物絮凝荆产生菌,在优化培养条件下所产微生物絮凝剂命名为M-127.将M-127用于染料废水脱色,实验结果表明,废水脱色的最佳条件是:100 mL染料废水中加入0.2 mL M-127和2.0mL CaCL2、体系pH值6.0,200 r/min搅拌1 min,60 r/min搅拌3min,静置15 min.M-127对染料废水的脱色率达到93.88%,同时m还研究了M-127在最佳条件下的脱色动力学m并得到了脱色动力学经验方程.