Impact of soil surface properties on soil swelling of different soil layers in collapsing wall of Benggang.

Benggang is one of the most serious soil erosion problems in tropical and subtropical areas in southern China. Little work has been reported on the surface properties of soil colloidal particle and its influence on soil swelling of different soil layers in collapsing wall of Benggang. In this present work, the effects of sodium concentration on soil swelling, and the correlations between soil swelling rates and soil colloidal surface properties were comprehensively evaluated by carefully examining soil physicochemical properties and soil colloidal surface properties of red, sandy and detritus soil layers from a collapsing wall. Our results showed that the soil swelling rates of red, sandy and detritus soil layers all exponentially decreased with increasing initial water contents. The relationship between soil swelling rate and the thickness of shear plane showed an extremely significant negative correlation for red soil layer and no correlation for sandy and detritus soil layers. Moreover, the elevating sodium concentrations reduced the thickness of shear plane from 39.69 to 0.76 nm for red soil layer, followed from 22.56 to 0.79 nm for sandy soil layer and from 18.61 to 0.64 nm for detritus soil layer. These findings indicated that the soil particle interactions played a crucial role in the development and occurrence of Benggang. This work will be helpful in understanding the mechanisms of soil mass loss on the gully head and collapsing wall of Benggang.

Mechanisms for potential Pb immobilization by hydroxyapatite in a soil-rice system.

This study aimed to investigate the mechanism of lead (Pb) immobilization by hydroxyapatite (HAP) in a soil-rice system, a pot experiment was conducted using Pb-contaminated soil amended with various rates of HAP and planted with rice (Oryza sativa L.). The Pb species in the soil and rice roots were determined using Pb L3-edge X-ray absorption near edge structure (XANES). Application of HAP increased soil pH and induced the dissolution of phosphate, subsequently promoting the formation of chloropyromorphite, an insoluble Pb species, in the soil. Therefore, the acid soluble and DTPA-extractable Pb concentrations decreased significantly with increasing levels of applied HAP. HAP reduced the retention of Pb in the iron plaque on the root surface at maturity, thereby alleviating Pb uptake by rice roots. The amount of phosphate in roots were increased with increasing rate of application of HAP, but was negatively correlated with Pb in rice stems and leaves. Application of 32 g kg-1 of HAP triggered the precipitation of Pb5PO4Cl in roots, limiting Pb translocation from roots to shoots. In addition, HAP may induce the redistribution of Pb in rice nodes, lowering the transfer factor of Pb from the stem (or leaf) to rice grains. When the rate of application of HAP exceeds 4 g kg-1, the Pb concentration in brown rice could be reduced to less than the Chinese National Standard of 0.2 mg kg-1 (GB2762-2017).

Removal of heavy metals from contaminated paddy soils using chemical reductants coupled with dissolved organic carbon solutions.

General acid washing is commonly used to treat heavy metal-contaminated soils, but it is sometimes difficult to achieve remediation aims in severely polluted soils. If we expose the surfaces of Fe oxide minerals to reductive dissolution during washing treatment, more of the metals initially adsorbed to these surfaces will be liberated, which may encourage the removal of heavy metals. Initially, the metal extraction capabilities of nine chemical reductants were compared in ten soil samples polluted by Cr, Cu, Zn, and Ni. Sodium dithionite (Na2S2O4) and ferrous sulfate (FeSO4) were screened for subsequent intensive research. In summary, the Na2S2O4 solutions had higher Cr, Cu, and Zn removal rates than either the FeSO4 or acid solution. Application of dissolved organic carbon (DOC) further increased the removal of heavy metals by complexation. About 15%, 86%, 32%, and 52% of the Cr, Cu, Zn, and Ni, respectively, were removed from the representative soil (M-2) by two-stage washing using 0.2 M Na2S2O4 coupled with 1,500 mg L-1 DOC solution at pH 2.0. Meanwhile, most soil fertility was preserved: ammonium nitrogen was increased 3.9 times; the increase in exchangeable potassium was 33%; and the reduction in available P was only 10%.

Soil Phosphorus Pools, Bioavailability and Environmental Risk in Response to the Phosphorus Supply in the Red Soil of Southern China.

Excess phosphorus (P) accumulation in the soil can change the bioavailability of P and increase the leaching risks, but the quantitative evaluation of these responses in acidic red soil is lacking. This study aimed to investigate the composition of soil P fractions under different phosphorus apparent balances (PAB) in acidic red soil and the bioavailability and the leaching change-points of different P fractions. Five phosphorus (P) fertilization rates were applied (0, 16.38, 32.75, 65.50, 131.00 kg P·ha-1) in every sweet corn cultivation from the field experiment, and the treatments were marked as P0, P1, P2, P3, and P4, respectively. The PAB showed negative values in P0 and P1 which were -49.0 and -15.0 kg P·ha-1 in two years, respectively. In contrast, PAB in P2 as well as in P3 and P4 were positive, the content ranging from 40.2 to 424.3 kg P·ha-1 in two years. Per 100 kg ha-1 P accumulate in the soil, the total P increased by 44.36 and 10.41 mg kg-1 in the surface (0-20 cm) and subsurface (20-40 cm) soil, respectively. The content of inorganic P fractions, including solution phosphate (Sol-P), aluminum phosphate (Al-P), iron phosphate (Fe-P), reduction phosphate (Red-P), and calcium phosphate (Ca-P), significantly increased by 0.25, 16.22, 22.08, 2.04, and 5.08 mg kg-1, respectively, in surface soil per 100 kg ha-1 P accumulated in the soil. Path analysis showed that the most important soil P fractions contributing to Olsen-P were Sol-P and Al-P, which can directly affect Olsen-P, and their coefficients were 0.24 and 0.73, respectively. Furthermore, the incubation experiments were conducted in the laboratory to investigate the leaching risk of different P fractions, and they showed Sol-P was a potential source of leaching, and the leaching change-points of Al-P and Fe-P were 74.70 and 78.34 mg·kg-1, respectively. Continuous P that accumulated in soil changed the composition of P fractions, and the bioavailability as well as the leaching risks increased. This is important in optimizing soil P fertilization management in agricultural ecosystems based on the bioavailability and critical levels for leaching of P fractions.

Adsorption mechanisms of chromate and phosphate on hydrotalcite: A combination of macroscopic and spectroscopic studies.

Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO4) and phosphate (PO4) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO4 and PO4 on HT were 0.16 and 0.23 mmol g-1. Regarding adsorption kinetics, CrO4 and PO4 adsorption on HT could be well described by the second order model, and the rate coefficient of CrO4 and PO4 on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO4 and PO4 were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO4 and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO4 adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO4. This study determined the adsorption behaviors of CrO4 and PO4 on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.

Removal of methylene blue from aqueous solution using sediment obtained from a canal in an industrial park.

Drainage canal sediments in an industrial park are generally dredged to landfill in Taiwan. The objective of this study was to evaluate feasibility employing the sediment as an adsorbent for removal of dye. The sediment contained approximately 10% of organic matter and little heavy metals. Infrared (IR) analysis revealed that carboxyl was the most important functional group for methylene blue (MB) sorption. Canal sediment could remove the most MB from water at pH 8.0 and this removal increased with increasing temperature. The MB sorption was well described by the Langmuir, Dubinin-Radushkevich, and Temkin sorption isotherms at 10°C, but it showed good compliance with Freundlich isotherm at 25°C and 40°C. The MB adsorption was a spontaneous and endothermic reaction; its maximum calculated adsorption capacity (Qm) was 56.0 mg g-1 at 10°C by the Langmuir isotherm. The calculated values of enthalpy (ΔH°) and entropy (ΔS°) are 14.6 kJ mol-1 and 149.2 kJ mol-1, respectively. Only pseudo-second-order adsorption kinetic model successfully described the kinetics of MB onto the sediment at different operation parameters. Activation energy of MB adsorption calculated from Arrhenius equation was 16.434 kJ mol-1, indicating the binding between canal sediment and MB was a physical adsorption.

Distribution and transformation of lead in rice plants grown in contaminated soil amended with biochar and lime.

This study aimed to investigate the effects of rice straw biochar and lime (RBL) on the remediation of lead (Pb)-contaminated soil and mitigation of Pb translocation in rice plants by using pot experiments. Lead-contaminated soil collected from a farmland near a Pb-zinc (Zn) mine, biochar, limestone powder, and indica rice (Oryza sativa L.) were used in the present study. The experimental treatments included: (1) control (CK), (2) 2.5% biochar (RB1), (3) 5% biochar (RB2), (4) 0.6% lime (L1), (5) 1.2% lime (L2), (6) 2.5% biochar + 0.6% lime (RBL1), and (7) 2.5% biochar + 1.2% lime (RBL2). The results revealed that the treatment with RBL was more efficient than the treatment with only biochar or lime in decreasing CaCl2-extractable Pb content in the soil by increasing soil pH and soluble sulfate content in the soil. Treatment with RBL reduced in the accumulation of Pb in the shoot of rice plants, this was mainly attributed to the decrease in the concentration of available Pb in the soil. The RBL2 treatment not only decreased the concentration of Pb in brown rice by 84.33% and Pb distribution in rice embryo, but also increased rice yield by 53.38% from that of the control. Further, unlike biochar treatment, RBL and lime treatments decreased the translocation of Pb in rice plants. The RBL treatment increased the proportion of Pb distributed in the cell wall and reduced the mobility of Pb in plant tissues. Thus, application of biochar and lime in combination is more effective than their individual application in reducing the availability of Pb in the soil and Pb accumulation in brown rice.

Cadmium phytoextraction potential of king grass (Pennisetum sinese Roxb.) and responses of rhizosphere bacterial communities to a cadmium pollution gradient.

Screening for tolerant and high biomass producing plants is important for phytoextraction efforts in remediating agricultural soils contaminated by heavy metals. We carried out a greenhouse experiment involving a soil cadmium (Cd) concentration gradient (0.1, 0.5, 1, 2, 4, and 8 mg kg-1) to assess growth and phytoextraction capacity of king grass (Pennisetum sinese Roxb.) in soils contaminated by Cd and to explore changes in diversity and structure of rhizosphere soil bacterial communities in response to long-term Cd pollution. A significant positive relationship was observed between Cd concentrations in P. sinese stems, leaves, and roots and soil Cd concentration. The highest Cd concentrations in shoots and roots were 28.87 and 34.01 mg kg-1, respectively, at 8 mg kg-1of soil Cd supply. Total extraction amounts of Cd in P. sinese were 0.22-1.86 mg plant-1 corresponding to treatment with 0.5-8 mg kg-1 Cd. Most of the Cd was stored in shoots, and the largest accumulation was 1.56 mg plant-1 with 54.02 g dry shoot weight. After phytoextraction, changes in rhizobacterial community composition were found with different levels of Cd application, whereas there were no clear trends in diversity and richness. Results of this study show the feasibility of P. sinese in accumulating Cd and provide support for its application in remediation of soil moderately contaminated by Cd.

Bacillus praedii sp. nov., isolated from purplish paddy soil.

A Gram-stain-positive, rod-shaped, endospore-forming, aerobic bacterium, designated strain FJAT-25547T, was isolated from the purplish paddy soil collected from Linshan Township, Yanting Prefecture of Sichuan Province in PR China (31° 16' N 105° 27' E). Growth was achieved aerobically at temperatures between 15 and 40 °C (optimum 30 °C), with between 0 and 10.0 % NaCl (w/v) (optimum 4 %) and in the range of pH 5.0-12.0 (optimum pH 9.0). The cell-wall peptidoglycan contained meso-diaminopimelic acid, and the main isoprenoid quinone was MK-7. The major fatty acids were iso-C15 : 0 (55.4 %), anteiso-C15 : 0 (22.2 %), iso-C16 : 0 (5.1 %) and iso-C14 : 0 (6.5 %). The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FJAT-25547T was a member of the genus Bacillus and was most closely related to Bacillus horneckiae DSM 23495T (97.7 % similarity), Bacillus eiseniae A1-2T (97.5 %), Bacillus mesophilum IITR-54T (97.2 %) and Bacillus kochii WCC 4582T (97.0 %). The average nucleotide identity value between strain FJAT-25547T and the type strain of the most closely related species, B. horneckiae DSM 23495T, was 77.7 %, less than the proposed cut-off value of 96.0 % for differentiating species within the genus. The in silico DNA-DNA hybridization value of strain FJAT-25547T with the most closely related species was 22.7 %, <70 %, again indicating they belong to different taxa. The DNA G+C content of strain FJAT-25547T was 39.1 mol%. This taxono-genomics study revealed that strain FJAT-25547T represents a novel species of the genus Bacillus for which the name Bacillus praedii sp. nov. (type strain FJAT-25547T=CCTCC AB 2015208T=DSM 101002T) is proposed.

Biochar amendment immobilizes lead in rice paddy soils and reduces its phytoavailability.

This study aimed to determine effects of rice straw biochar on Pb sequestration in a soil-rice system. Pot experiments were conducted with rice plants in Pb-contaminated paddy soils that had been amended with 0, 2.5, and 5% (w/w) biochar. Compared to the control treatment, amendment with 5% biochar resulted in 54 and 94% decreases in the acid soluble and CaCl2-extractable Pb, respectively, in soils containing rice plants at the maturity stage. The amount of Fe-plaque on root surfaces and the Pb concentrations of the Fe-plaque were also reduced in biochar amended soils. Furthermore, lead species in rice roots were determined using Pb L3-edge X-ray absorption near edge structure (XANES), and although Pb-ferrihydrite complexes dominated Pb inventories, increasing amounts of organic complexes like Pb-pectins and Pb-cysteine were found in roots from the 5% biochar treatments. Such organic complexes might impede Pb translocation from root to shoot and subsequently reduce Pb accumulation in rice with biochar amendment.

Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal.

Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecipitates in relation to their surface and structural properties was investigated. While dissolved silicate increased with increasing pH from Fe/Si coprecipitates, less than 7% of silicate was discernible from Al/Si samples over the range from acidic to alkaline conditions. Our spectroscopic results showed that the associations between Al and Si were relatively stronger than that between Fe and Si in coprecipitates. In Al/Si coprecipitates, core-shell structures were developed with AlO6/AlO4 domains as the shells and Si frameworks polymerized from the SiO2 as the cores. However, Si framework remained relatively unchanged upon coprecipitation with Fe hydroxides in Fe/Si samples. The Si core with Al shell structure of Al/Si coprecipitates shielded the negative charges from SiO2 and thereby resulted in a higher adsorption capacity of selenite than Fe/Si coprecipitates.

Effectiveness of lime and peat applications on cadmium availability in a paddy soil under various moisture regimes.

In paddy soils, amendments and moisture play important role in the immobilization of cadmium (Cd). The effects of applying lime, peat, and a combination of both on soil Eh, pH, and Cd availability in contaminated soils were investigated under wetted (80 ± 5 % of water holding capacity) and flooded (completely submerged) conditions. In wetted soils, there was little change in Eh, compared to flooded soils where Eh reduced rapidly. Amendments of lime only or in a mixture with peat increased soil pH to different degrees, depending on the lime application rate. However, peat addition only slightly affected soil pH. The decreased Cd availability in flooded soils was related to submergence duration and was significantly lower than that in wetted soils after 14 days. Liming wetted and flooded soils decreased exchangeable Cd and increased carbonates or Fe-Mn oxides bound fractions, while peat addition transformed Cd from carbonates to organic matter bound fractions. The combined application of peat and lime generally showed better inhibitory effects on the availability of Cd than separately application of lime or peat. Higher application rates of lime, peat, or their mixture were more effective at reducing Cd contamination in flooded soil. This indicates that application of peat and lime mixture under flooded conditions was most effective for in situ remediation of Cd-contaminated soils. Further studies are required to assess the long-term effectiveness of the peat and lime mixture on Cd availability in paddy soils.

Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

Shifts in the pelagic ammonia-oxidizing microbial communities along the eutrophic estuary of Yong River in Ningbo City, China.

Aerobic ammonia oxidation plays a key role in the nitrogen cycle, and the diversity of the responsible microorganisms is regulated by environmental factors. Abundance and composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated in the surface waters along an environmental gradient of the Yong River in Ningbo, East China. Water samples were collected from three pelagic zones: (1) freshwaters in the urban canals of Ningbo, (2) brackish waters in the downstream Yong River, and (3) coastal marine water of Hangzhou Bay. Shifts in activity and diversity of the ammonia-oxidizing microorganisms occurred simultaneously with changes in environmental factors, among which salinity and the availabilities of ammonium and oxygen. The AOA abundance was always higher than that of AOB and was related to the ammonia oxidation activity. The ratios of AOA/AOB in the brackish and marine waters were significantly higher than those found in freshwaters. Both AOA and AOB showed similar community compositions in brackish and marine waters, but only 31 and 35% similarity, respectively, between these waters and the urban inland freshwaters. Most of AOA-amoA sequences from freshwater were affiliated with sequences obtained from terrestrial environments and those collected from brackish and coastal areas were ubiquitous in marine, coastal, and terrestrial ecosystems. All AOB from freshwaters belonged to Nitrosomonas, and the AOB from brackish and marine waters mainly belonged to Nitrosospira.

Mechanism of Arsenic Adsorption on Magnetite Nanoparticles from Water: Thermodynamic and Spectroscopic Studies.

Removal of arsenic (As) from water supplies is needed to reduce As exposure through drinking water and food consumption in many regions of the world. Magnetite nanoparticles (MNPs) are promising and novel adsorbents for As removal because of their great adsorption capacity for As and easy separation. This study aimed to investigate the adsorption mechanism of arsenate, As(V), and arsenite, As(III), on MNPs by macroscopic adsorption experiments in combination with thermodynamic calculation and microspectroscopic characterization using synchrotron-radiation-based X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). Adsorption reactions are favorable endothermic processes as evidenced by increased adsorption with increasing temperatures, and high positive enthalpy change. EXAFS spectra suggested predominant formation of bidentate binuclear corner-sharing complexes ((2)C) for As(V), and tridentate hexanuclear corner-sharing ((3)C) complexes for As(III) on MNP surfaces. The macroscopic and microscopic data conclusively identified the formation of inner-sphere complexes between As and MNP surfaces. More intriguingly, XANES and XPS results revealed complex redox transformation of the adsorbed As on MNPs exposed to air: Concomitant with the oxidation of MNPs, the oxidation of As(III) and MNPs was expected, but the observed As(V) reduction was surprising because of the role played by the reactive Fe(II).

Bacillus taiwanensis sp. nov., isolated from a soil sample from Taiwan.

A Gram-stain-positive, rod-shaped, endospore-forming, aerobic bacterium (FJAT-14571(T)) was isolated from a soil sample in Taiwan. Strain FJAT-14571(T) grew at 20-40 °C (optimum 35 °C), pH 6-10 (optimum pH 8) and 0-2% (w/v) NaCl (optimum 0%). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FJAT-14571(T) was a member of the genus Bacillus and was most closely related to Bacillus oceanisediminis DSM 24771(T) (96.2%). DNA-DNA relatedness between strain FJAT-14571(T) and B. oceanisediminis DSM 24771(T) was low (32.0% ± 0.88%). The diagnostic diamino acid of the peptidoglycan of strain FJAT-14571(T) was meso-diaminopimelic acid and the predominant menaquinone was MK-7 (96.6%). The major cellular fatty acids were iso-C15 : 0 (46.4%), anteiso-C15 : 0 (7.6%), iso-C17 : 0 (8.2%) and iso-C16 : 0 (10.0 %) and the DNA G+C content was 40.8 mol%. Phenotypic, chemotaxonomic and genotypic properties clearly indicated that strain FJAT-14571(T) represents a novel species within the genus Bacillus, for which the name Bacillus taiwanensis sp. nov. is proposed. The type strain is FJAT-14571(T) ( = DSM 27845(T) = CGMCC1.1 2698(T)).

Kinetic and thermodynamic studies on removal of Cu(II) from aqueous solutions using soil nanoclays.

Soil clays (< 2,000 nm) (SC) and soil nanoclays (< 100 nm) (SNC) were used as adsorbents for removal of Cu(II) from aqueous solution. The experiments were conducted with variables including pH, interaction time, concentration of Cu(II) and temperature. Four kinetic models have been employed to investigate adsorption mechanisms, and the experimental data more closely resemble a second-order process of the kinetic model. Adsorption studies on soil nanoclays have been shown to be highly effective in removing of Cu(II) from aqueous solution. This adsorbent is widely available as a natural material, is mechanically stable and, most importantly, it is environmentally appealing. The maximum Cu(II) adsorption capacity of soil nanoclays (31.7 mg/g) is more than three times higher than natural soil clays (10.2 mg/g). Our study demonstrates that soil nanoclays can be used effectively for removal of Cu(II) from aqueous systems to achieve environmental cleaning purposes.

Bacillus cihuensis sp. nov., isolated from rhizosphere soil of a plant in the Cihu area of Taiwan.

A Gram-positive, moderately halotolerant, rod-shaped, spore forming bacterium, designated strain FJAT-14515(T) was isolated from a soil sample in Cihu area, Taoyuan County, Taiwan. The strain grew at 10-35 °C (optimum at 30 °C), pH 5.7-9.0 (optimum at pH 7.0) and at salinities of 0-5 % (w/v) NaCl (optimum at 1 % w/v). The diagnostic diamino acid of the peptidoglycan of the isolated strain was meso-diaminopimelic acid and major respiratory isoprenoid quinone was MK-7. Major cellular fatty acids were anteiso-C15:0 (40.6 %), iso-C15:0 (20.7 %) and the DNA G+C content of strain FJAT-14515(T) was 37.1 mol %. A phylogenetic analysis based on 16S rRNA gene sequences indicated that strain FJAT-14515(T) belongs to the genus Bacillus, and was most closely related to the reference strains of Bacillus muralis DSM 16288(T) (97.6 %) and Bacillus simplex DSM 1321(T) (97.5 %). Levels of DNA-DNA relatedness between strain FJAT-14515(T) and the reference strains of B. muralis DSM 16288(T) and B. simplex DSM 1321(T) were 27.9 % ± 3.32 and 44.1 % ± 0.57, respectively. Therefore, on the basis of phenotypic, chemotaxonomic and genotypic properties, strain FJAT-14515(T) represents a novel species of the genus Bacillus, for which the name Bacillus cihuensis sp. nov. is proposed. The type strain is FJAT-14515(T) (=DSM 25969(T) = CGMCC 1.12697(T)).

Biogeochemical reductive release of soil embedded arsenate around a crater area (Guandu) in northern Taiwan using X-ray absorption near-edge spectroscopy.

This study investigates biogeochemical reductive release of arsenate from beudantite into solution in a crater area in northern Taiwan, using a combination of X-ray absorption near-edge structure (XANES) and atomic absorption spectrometry. Total arsenic (As) concentrations in the soil were more than 200 mg/kg. Over four months of laboratory experiments, less than 0.8% As was released into solution after reduction experiments. The 71% to 83% As was chemically reduced into arsenite (As(III)) and partially weathering into the soluble phase. The kinetic dissolution and re-precipitation of As, Fe, Pb and sulfate in this area of paddy soils merits further study.

Adsorption of Cu(II) from aqueous solution by wine processing waste sludge.

Wine processing waste sludge (WPWS) has been shown to be an effective sorbent for sorption of nickel, lead, and chromium, but the sorption of copper (Cu) in aqueous solution by WPWS has not been conducted. The objective of this study was to explore the sorption mechanism of WPWS for copper. Infrared analysis revealed carboxyl was the major functional group in WPWS. The WPWS sorption isotherms of copper were only well described by Langmuir sorption isotherm. The maximum adsorption capacity (Qm) was 14.26 mg/g at 50 degrees C. A pseudo-second-order sorption kinetic model successfully described the kinetics of copper sorption onto WPWS. The Gibb free energies (deltaG0) ranged from -20.69 to -24.29 kJ mol(-1), and the deltaH0 and deltaS0 were 5.048 kJ mol(-1) and 91.05 J mol(-1) K(-1), respectively. The trend of the intra-particular diffusion rate is the opposite of the adsorption constant of the pseudo-second-order equation.