Interaction of Pseudomonas putida with kaolinite and montmorillonite: a combination study by equilibrium adsorption, ITC, SEM and FTIR

Equilibrium adsorption along with isothermal titration calorimetry (ITC), Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM) techniques were employed to investigate the adsorption of Pseudomonas putida on kaolinite and montmorillonite. A higher affinity as well as larger amounts of adsorption of P. putida was found on kaolinite. The majority of sorbed bacterial cells (88.7%) could be released by water from montmorillonite, while only a small proportion (9.3%) of bacteria desorbed from kaolinite surface. More bacterial cells were observed to form aggregates with kaolinite, while fewer cells were within the larger bacteria–montmorillonite particles. The sorption of bacteria on kaolinite was enthalpically more favorable than that on montmorillonite. Based on our findings, it is proposed that the non-electrostatic forces other than electrostatic force play a more important role in bacterial adsorption by kaolinite and montmorillonite. Adsorption of bacteria on clay minerals resulted in obvious shifts of infrared absorption bands of water molecules, showing the importance of hydrogen bonding in bacteria–clay mineral adsorption. The enthalpies of −4.1 ± 2.1 × 10⁻⁸ and −2.5 ± 1.4 × 10⁻⁸ mJ cell⁻¹ for the adsorption of bacteria on kaolinite and montmorillonite, respectively, at 25 °C and pH 7.0 were firstly reported in this paper. The enthalpy of bacteria–mineral adsorption was higher than that reported previously for bacteria–biomolecule interaction but lower than that of bacterial coaggregation. The bacteria–mineral adsorption enthalpies increased at higher temperature, suggesting that the enthalpy–entropy compensation mechanism could be involved in the adsorption of P. putida on clay minerals. Data obtained in this study would provide valuable information for a better understanding of the mechanisms of mineral–microorganism interactions in soil and associated environments.     

Effects of low-molecular-weight organic ligands and phosphate on adsorption of Pseudomonas putida by clay minerals and iron oxide

Adsorption of Pseudomonas putida on kaolinite, montmorillonite and goethite was studied in the presence of organic ligands and phosphate. Citrate, tartrate, oxalate and phosphate showed inhibitive effect on P. putida adsorption by three minerals in a broad range of anion concentrations. The highest efficiencies of the four ligands in blocking the adsorption of P. putida on goethite, kaolinite and montmorillonite were 58–90%, 35–76% and 20–48%, respectively. The ability of organic ligands in prohibiting the binding of P. putida cells to the minerals followed the sequence of citrate > tartrate > oxalate > acetate. The significant suppressive effects on P. putida adsorption were ascribed to the increased negative charges by adsorbed ligands and the competition of ligands with bacterial surface groups for binding sites. The inhibitive effects on P. putida adsorption by organic ligands were also dependent on the steric hindrance of the molecules. Acetate presented promotive effect on P. putida adsorption by kaolinite and goethite at low anion concentrations. The results obtained in this study suggested that the adsorption of bacteria in soils especially in the rhizosphere can significantly be impacted by various organic and inorganic anions.     

Immobilization of heavy metals by Pseudomonas putida CZ1/goethite composites from solution

Bacterial–mineral composites are important in the retention of heavy metals due to their large sorption capacity under a wide range of environmental conditions. This study provides the first quantitative comparison of the metal-binding capacities of P. putida CZ1–goethite composite to its individual components. When the same amount (on a dry weight basis) of living and nonliving cells of P. putida CZ1, goethite or their composites was separately exposed to solutions of 0.5 mM Cu(II) and Zn(II) in 0.01 M KNO₃, the living cells removed the largest quantity of heavy metals. The results of calculated metal retention values indicated that the adsorption of goethite to bacteria has not mask or neutralize chemically reactive adsorption sites normally available to metal ions. Moreover, the nonliving cells–goethite composite retained approximately 82% more Zn than that predicted by their individual behavior. The preferential association of Zn with P. putida CZ1 was observed by TEM and EDS analyses of a mixture consisting of the bacteria and goethite. Desorption of Cu and Zn with 1.0 M CH₃COOK solution from P. putida CZ1 and goethite indicated the differences in the functional groups able to bind heavy metals.     

Adsorption of a few heavy metals on natural and modified kaolinite and montmorillonite: a review

The feasibility of using two important and common clay minerals, kaolinite and montmorillonite, as adsorbents for removal of toxic heavy metals has been reviewed. A good number of works have been reported where the modifications of these natural clays were done to carry the adsorption of metals from aqueous solutions. The modification was predominantly done by pillaring with various polyoxy cations of Zr4+, Al3+, Si4+, Ti4+, Fe3+, Cr3+or Ga3+, etc. Preparation of pillared clays with quaternary ammonium cations, namely, tetramethylammonium-, tetramethylphosphonium- and trimethyl-phenylammonium-, N'-didodecyl-N, N'-tetramethylethanediammonium, etc, are also common. Moreover, the acid treatment of clays often boosted their adsorption capacities. The adsorption of toxic metals, viz., As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Zn, etc., have been studied predominantly. Montmorillonite and its modified forms have much higher metal adsorption capacity compared to that of kaolinite as well as modified-kaolinite.     

Adsorption of nitrobenzene andn-pentanol from aqueous solution on hydrophilic and hydrophobic clay minerals

The sorption of nitrobenzene andn-pentanol from dilute aqueous solution on swelling clay minerals and their organophilized derivatives (organo clays) was studied. Adsorption excess isotherms were obtained by the immersion method. The basal spacings of the clay minerals were determined by X-ray diffraction measurements. By combining these two independent methods, composition and structure of the interlamellar space could be calculated. On the hydrophilic surface of montmorillonite negative adsorption of the organic component was observed at low molar fractions of nitrobenzene or pentanol, i.e., water was preferentially adsorbed. On organophilized montmorillonite and vermiculite adsorption of nitrobenzene and pentanol was positive over the whole range of liquid composition. The amount of interlamellar alkyl chains which is determined by the surface charge of clay mineral inversely affected the adsorption of both solutes.     

Investigation into the adsorption of CO2, N2 and CH4 on kaolinite clay

Investigating the adsorption characteristics of CO₂, N₂ and CH₄ on kaolinite clay is beneficial for enhanced shale gas recovery by gas injection. In this paper, the experiments of CO₂, N₂ and CH₄ adsorption at 288 K, 308 K and 328 K on kaolinite clay were conducted, and the thermodynamics analysis of adsorption of three gases was performed. The findings reveal that the order of the uptakes of three gases on kaolinite clay is as follows: N₂ < CH₄ < CO₂. Reducing temperature enlarges the separation coefficients of CO₂ over CH₄ (α_CO2/CH4), CO₂ over N₂ (α_CO2/N2), and CH₄ over N₂ (α_CH4/N2). The value of α_CO2/CH4 greater than one validates that CO₂ is capable to directly replace the pre-adsorbed CH₄. The spontaneity of CO₂ adsorption is the highest, while N₂ has the lowest adsorption spontaneity. Injecting N₂ into gas-bearing reservoir can cause CH₄ desorption by lowering the spontaneity of CH₄ adsorption. Adsorbed CO₂ molecules form a most ordered rearrangement on kaolinite surface. The decrease rate of entropy loss for N₂ adsorption is higher than those for CO₂ and CH₄ adsorption.     

Adsorption behavior of Pb(II) on montmorillonite

The present work investigated the adsorption and desorption behaviors of Pb(II) on montmorillonite. The adsorption experiments were carried out using batch process. The results show that the adsorption is dependent on the pH value of the medium, and the uptake of Pb(II) increases with the pH increasing in the pH range of 2.0–10.0. The adsorption kinetics is in better agreement with pseudo-second order kinetics, and the adsorption data is a good fit with Langmuir isotherm. The presence of EDTA may result in a decrease of the amount of Pb(II) adsorbed. The presence of electrolyte and EDTA may enhance the desorption of Pb(II) ions adsorbed. The adsorption mechanism of Pb(II) on montmorillonite may be explained in two aspects: the chemical binding between Pb(II) ions and surface hydroxyl groups; and the electrostatic binding between Pb(II) ions and the permanent negatively charged sites of montmorillonite.     

Preferential adsorption of extracellular polymeric substances from bacteria on clay minerals and iron oxide

The adsorption of extracellular polymeric substances (EPS) from Bacillus subtilis on montmorillonite, kaolinite and goethite was investigated as a function of pH and ionic strength using batch studies coupled with Fourier transform infrared (FTIR) spectroscopy. The adsorption isotherms of EPS on minerals conformed to the Langmuir equation. The amount of EPS-C and -N adsorbed followed the sequence of montmorillonite>goethite>kaolinite. However, EPS-P adsorption was in the order of goethite>montmorillonite>kaolinite. A marked decrease in the mass fraction of EPS adsorption on minerals was observed with the increase of final pH from 3.1 to 8.3. Calcium ion was more efficient than sodium ion in promoting EPS adsorption on minerals. At various pH values and ionic strength, the mass fraction of EPS-N was higher than those of EPS-C and -P on montmorillonite and kaolinite, while the mass fraction of EPS-P was the highest on goethite. These results suggest that proteinaceous constituents were adsorbed preferentially on montmorillonite and kaolinite, and phosphorylated macromolecules were absorbed preferentially on goethite. Adsorption of EPS on clay minerals resulted in obvious shifts of infrared absorption bands of adsorbed water molecules, showing the importance of hydrogen bonding in EPS adsorption. The highest K values in equilibrium adsorption and FTIR are consistent with ligand exchange of EPS phosphate groups for goethite surface. The information obtained is of fundamental significance for understanding interfacial reactions between microorganisms and minerals.     

甘氨酸在高岭土表面的吸附和热缩合反应

采用TG/DTA、FT-IR和in situ DRIFT等技术对甘氨酸在高岭土表面的吸附和热缩合反应进行了表征, 考察了甘氨酸平衡浓度和溶液pH值对吸附行为的影响, 同时探讨了原位条件下甘氨酸的缩合反应历程. 结果表明, 溶液呈弱酸性时, 甘氨酸在高岭土上的吸附量最大, 但吸附等温线不符合Langmuir模型. 在强酸性、弱酸性和碱性溶液中, 吸附态的甘氨酸分别主要以阳离子、两性离子和阴离子形式存在. 弱酸性溶液中, 甘氨酸的—NH3+基团与高岭土表面的≡S—O−(S为Si或Al)基团之间的氢键作用是吸附的主要驱动力, 而强酸性溶液中, ≡S—O−基团的质子化, 以及碱性溶液中—NH3+向—NH2的转化, 是导致吸附量下降的主要原因. In situ DRIFT结果表明, 在110−160 ℃温区, 有明显的线式二肽形成; 随着温度升高至210 ℃时, 二肽进一步脱水, 形成环化缩合产物哌嗪二酮(DKP). 没有检测到硅酯类或铝酯类中间体的特征峰, 反应可能按氢键促进下的自缩合机理进行, 高岭土的存在使缩合反应温度有明显降低.     

Adsorption and spectral studies of 3,6-diaminoacridine adsorbed on montmorillonite clay and cellulose

Montmorillonite-and cellulose-adsorbed 3,6-diaminoacridine are prepared. The adsorption isotherm studies show that while 3,6-diaminoacridine molecules are adsorbed in the interlayer spaces of the montmorillonite clay, the dye molecules are adsorbed on the surface of cellulose. Quenching studies reveal that the Al³⁺ ions of the aluminosilicate layers of the clay also quench the excited state emission of the adsorbed 3,6-diaminoacridine.     

Polydisperse fractal aggregate formation in clay mineral and iron oxide suspensions, pH and ionic strength dependence

pH- and ionic-strength-dependent aggregation of permanently and conditionally charged clay mineral (montmorillonite) and iron oxide (magnetite) particles was investigated by means of dynamic light scattering and rheology. An indifferent electrolyte (NaCl) was used. The surface charging of solids was determined by acid–base titration. The point of zero charge (PZC) of magnetite seemed to be at pH 8.0 ± 0.1. The permanent negative charges on the basal plane of montmorillonite influence the interfacial distribution of H⁺ and Na⁺ ions. The pH dependence of the electrophoretic mobility showed directly the dominance of negative charges on montmorillonite lamellae independently of pH, while for magnetite the sign of the mobility reversed at pH ˜ 8.0. Montmorillonite particles formed stable suspensions; coagulation did not take place below 35 mM 1:1 electrolyte independently of pH. The aggregation of magnetite sol becomes significant near the pH of the PZC even at low ionic strength. Colloidal stability in composite systems was investigated at pH ˜ 4, where oxide and clay mineral particles are oppositely charged. At the lowest NaCl concentrations (1, 5 mM) the mixed systems remained stable and aggregation of oppositely charged particles could not be observed at all. Heterocoagulation of dissimilar particles needed a definite amount of dissolved electrolytes (about 8 mM). Mixed clay mineral and oxide systems are more sensitive to electrolyte under acidic conditions than those separately. Rheological investigation of the mixed clay mineral–oxide suspensions at pH ˜ 4 provided proof for the absence of attractive particle interaction at low ionic strength (2 mM). A physical network of oppositely charged particles could form only at higher salt concentration, for example, in the presence of 10 mM NaCl. The yield value of plastic systems showed a significant maximum at 1:15 magnetite/montmorillonite mass ratio. Received: 21 November 2000 Accepted: 20 December 2000     

Release of cationic drugs from loaded clay minerals

The adsorption of promethazine chloride [10-(2-dimethylammonium propyl) fenothiazine chloride] and buformin hydrochloride (1-butylbiguanidine chloride) on montmorillonite was studied in previous work. The present article focuses on the desorption of these molecules from their organocomplexes in a medium of artificial intestinal juice (pH 7.0 ± 0.1) at the temperature of the human body (37 ± 0.5 °C). The desorption was investigated by kinetic studies, basal spacing measurements and Fourier transform IR studies. Important quantitative differences were observed: buformin, which adsorbed in a monolayer coverage, exhibited a very high desorption rate, whereas promethazine formed a pseudotrilayer arrangement and showed a lower dissolution rate. Received: 20 January 2001 Accepted: 8 March 2001     

Adsorption of oleic acid and triolein onto various minerals and surface treated minerals

A systematic investigation of the adsorption of oleic acid was under-taken with various minerals and surface treated minerals, viz., kaolinite, treated kaolinites, montmorillonites, talcs, gibbsites, calcites and a treated calcite. Adsorption onto kaolinite, two of the treated kaolinites (amine and MgSiO₃ treated), talcs and gibbsites was well correlated by the Langmuir model, while adsorption on the treated calcite was well correlated by the Freundlich model. Adsorption on a cationic polymer-treated kaolinite was explained in terms of a cooperative mechanism. Adsorption onto montmorillonites was explained in terms of a penetrative mechanism involving exchangeable cations.Oleic acid adsorption was compared with triolein adsorption on one of the montmorillonites, two adsorbents produced by the surface treatment of this montmorillonite, and one of the talcs. The triolein adsorption of the montmorillonite was considerably less than its oleic acid adsorption, and was explained in terms of a cooperative mechanism. Triolein adsorption of the treated montmorillonites, and the talc was well correlated by the Langmuir model. Larger amounts of triolein were taken up by the treated montmorillonites than by the untreated montmorillonite. The triolein adsorption of the talc was greater than its oleic acid adsorption.     

Effect of iron and humic acid on photodegradation of some pesticides adsorbed on clay surfaces

Photochemistry studies can be helpful in assessing the environmental fate of chemicals. For this reason, the photodegradation kinetic studies of the two pesticides orthophenylphenol (OPP) and monuron, largely used in agriculture, were carried out in solid phase. The fungicide OPP and the herbicide monuron were irradiated on the clay fractions (montmorillonite and modified clays) using a suntest simulator. The phototransformation of the parent compound was followed by HPLC technique. The photodegradation process appears to follow the first order reaction. Kinetic parameters were determined and the experimental results show that the photodegradation of these substrates was enhanced in presence of K-montmorillonite, in comparison with Fe(III) exchanged montmorillonite and montmorillonite complexed with humic acid complexes. This study has shown that the iron and humic acid adsorbed on clay surfaces did not increase the degradation rate.     

Application of Brazilian kaolinite clay as adsorbent to removal of U(VI) from aqueous solution: Kinetic and thermodynamic of cation-basic interactions

The compound N¹-[3-(trimethoxysilyl)propyl]diethylenetriamine was anchored onto Amazon kaolinite surface by heterogeneous route. The modified and natural kaolinite samples were characterized by transmission electron microscopy, scanning electron microscopic, X-ray diffraction, and nuclear magnetic nuclei of ²⁹Si and ¹³C. The well-defined peaks obtained in the ¹³C NMR spectrum in the 5.0-62.1 ppm region confirmed the attachment of organic functional groups as pendant chains bonded into the porous clay. The ability of these materials to remove U(VI) from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature and pH 4.0. The kinetic parameters analyzed by the Lagergren and Elovich models gave a good fit for a pseudo-second order reaction with k₂ values 16.0 and 25.1 mmol g⁻¹ min⁻¹ ranges for natural and modified kaolinite clays, respectively. The energetic effects caused by metal ion adsorption were determined through calorimetric titrations.     

恶臭假单胞菌与土壤矿物的界面反应及其对甲基对硫磷降解影响

研究了恶臭假单胞菌在蒙脱石、高岭石和针铁矿表面的吸附特征,探讨了细菌在不同粘粒矿物存在下的生长代谢活性,及对甲基对硫磷的降解动力学.结果表明, 三种矿物对细菌的吸附强度为针铁矿>高岭石>蒙脱石.当甲基对硫磷浓度较低时(10 mg/L), 游离菌的降解能力始终比固定菌强;在高浓度(20～40 mg/L)下, 固定菌对农药的降解能力起初(前9 h)高于游离菌, 随后渐渐低于游离菌.不同矿物固定的细菌, 其降解能力为蒙脱石>高岭石>针铁矿.蒙脱石对细菌的亲和力最弱, 但它对细菌的代谢活性有促进作用, 有利于农药的生物降解; 而针铁矿与细菌的结合强度最大, 细菌活性受到抑制, 不利于农药的降解.     

铀酰离子吸附在高岭土基面的分子动力学模拟

为研究铀酰离子在高岭土不同基面上的吸附, 对含有0.01 mol·L^-1碳酸铀酰液相和9×9×3个高岭土单胞的粘土固相的模拟盒子进行了分子动力学模拟. 从模拟的截图中直观地观察到了铀酰离子的吸附位点, 由径向分布函数得到了铀酰离子与水中氧原子的配位情况. 利用原子密度剖面图讨论铀酰离子在两个基面上的吸附倾向, 并从原子密度剖面图和均方位移等角度证实了铀酰离子在硅氧面上形成了外界配合物. 从理论上证明了表面配合模型对于吸附位点所做简化的合理性.     

Adsorption kinetics of fluoride on iron(III)-zirconium(IV) hybrid oxide

Fluoride occurs in some drinking water sources at levels that are hazardous to health. Tests were conducted to assess the ability of a mineral-based adsorbent to take-up fluoride ion. Consequently, in search of novel adsorbent media, crystalline and hydrous iron(III)-zirconium(IV) hybrid oxide (IZHO) was synthesized, and tested to determine its capacity and kinetics for fluoride adsorption. The Fourier Transform Infrared (FTIR) spectrum of IZHO indicated the presence of Fe–O–Zr linkage which showed hybrid nature of the synthetic oxide. The optimum pH range for fluoride adsorption was ranged between 4.0 and 7.0. The analyses of the isotherm equilibrium data using the Langmuir and the Redlich–Peterson model equations by linear and non-linear methods showed that the data fitted better with latter model than the former. Thermodynamic analysis showed spontaneous nature of fluoride adsorption, and that took place with the increase of entropy. The kinetic data obtained for fluoride adsorption on IZHO at pH 6.8 (±0.1) and room temperature (303±2 K) described both the pseudo-first order and the reversible first-order equations equally well (r ²= ∼0.98–0.99), and better than pseudo second order equation (r ²= ∼0.96–0.98) for higher concentrations (12.5 and 25.0 mg/dm³) of fluoride. The kinetics of fluoride adsorption on the mixed oxide took place with boundary layer diffusion. External mass transport with intra-particle diffusion phenomena governed the rate limiting process, which has been confirmed from the Boyd poor non-linear kinetic plots.     

1,3,5-三硝基苯在高岭石表面吸附的理论研究

构造了高岭石硅氧层和铝氧层的团簇模型(分别为Si₁₃O₃₇H₂₂和Al₆O₂₄H₃₀), 并分别在B3LYP/6-31G(d), MP2/6-31G(d)//B3LYP/6-31G(d)和B3LYP/6-311++G(d,p)//B3LYP/6-31G(d)理论水平上对1,3,5-三硝基苯(TNB)在高岭石表面的吸附性质(如优化的几何构型、 结构参数、 吸附能、 振动频率、 静电势和分子轨道等)进行了研究. 结果表明, TNB和硅氧层表面间的相互作用以静电和范德华相互作用为主; TNB与铝氧层间的相互作用以氢键为主, 且TNB和铝氧层间相互作用的能量更低, 结构更稳定.