Adsorption and solubility of ten metals in soil samples of different composition

We conducted batch experiments for ten metals [Mg, Cr(III), Fe(III), Co, Ni, Cu, Zn, Sr, Cd, Pb] and four soil samples of different composition to determine the relation of the soluble fraction (’intensity’︁) to an adsorbed or precipitated metal pool (’quantity’︁) and, thus, to investigate the buffer function of soils. The soil samples were spiked with 6 to 12 exponentially increasing metal doses added as metal nitrates. The native metal pool involved in sorption processes was characterized by an extraction with 0.025 M (NH₄)₂EDTA (pH 4.6). The quantity-intensity (Q/I) relations of eight metals [except Cr(III) and Fe(III)] were governed by sorption and complexation processes and can be fitted by Freundlich isotherms. Q/I relations for Cr(III) and two soils indicate a sorption maximum, which can be approximated with the Langmuir isotherm. In a calcareous soil high Cr doses induced the precipitation of a Cr oxide. The solution concentrations of Fe are primarily a function of the pH-dependent solubility of ferrihydrite. For all metals pH was the predominant factor controlling the partitioning between the solid and the liquid phase. Drastic losses in the buffer function of soils primarily occurred in the slightly acidic range. Furthermore, adsorption was also metal specific. On the basis of median Freundlich K values, adsorption increased in the order [median K_F values and K_F range (mg kg^—1) in brackets]: Mg (2.9: 0.9—19) < Sr (4.7: 0.6—21) << Co (17.7: 1.1—143) < Zn (26.7: 1.8—301) = Ni (27.6: 2.4—120) < Cd (71: 2.5—405) << Cr(III) (329: 45—746) < Cu (352: 30—1200) < Pb (1730: 76—4110).     

Physicochemical property guidelines for modern agrochemicals

The relentless need for the discovery and development of new agrochemicals continues as a result of driving forces such as loss of existing products through the development of resistance, the necessity for products with more favorable environmental and toxicological profiles, shifting pest spectra, and the changing agricultural needs and practices of the farming community. These new challenges underscore the demand for novel, high‐quality starting points to accelerate the discovery of new agrochemicals that address market challenges. This article discusses the efforts to identify the optimum ranges of physicochemical properties of agrochemicals through analysis of modern commercial products. Specifically, we reviewed literature studies examining physicochemical property effects and analyzed the properties typical of successful fungicides, herbicides, and insecticides (chewing and sap‐feeding pests). From the analysis, a new set of physicochemical property guidelines for each discipline, as well as building block class, are proposed. These new guidelines should significantly aid in the discovery of next‐generation agrochemicals. © 2018 Society of Chemical Industry     

Comparison of lignin and cellulose solubilities in ionic liquids by COSMO-RS analysis and experimental validation

In this work, the solubilities of lignin and cellulose in ionic liquids (ILs) have been analyzed and compared by COSMO-RS simulation. The excess enthalpy of the IL + lignin/cellulose mixtures is evaluated as reference property to describe the affinity of lignin and cellulose for different ionic liquids, in terms of the intermolecular interactions contributing to their mixing properties. Thus, the anion plays the main role in the dissolution process of both lignin and cellulose, in which the hydrogen bonding forces are the major interactions. The most promising anions for the cellulose and lignin dissolution are acetate, formate and chloride, whereas different cations can be employed. Computational results indicated that a rational combination of the anions and cations allows designing ILs able to dissolve with different selectivity lignin and cellulose. Some of these solutions are tested in the laboratory to validate the model employed and the regenerated solids are analyzed by FTIR spectroscopy.     

Color Removal from the Dark Muscle of Alaskan Pollock (Theragra chalcogramma) Fillets and Minces Using Peroxide

The effectiveness of hydrogen peroxide (0.85-2.0% by weight) and sodium tripolyphosphate (0-2.0% by weight) at different pH (pH 4.5-10.5) applied as a surface treatment or by injection into the fillet for bleaching the dark muscle of Alaskan pollock (Theragra chalcogramma) was evaluated. At a pH of 8.5-10.5 combinations 0.85-2% sodium tripolyphosphate and 0.85-2% hydrogen peroxide were effective in reducing the color of the dark muscle in intact fillets and minces. At higher levels of peroxide, lightening was generally accompanied by higher yellow (+b) values for fillets and minced dark muscle tissue.     

竹红菌甲素固体分散体的制备及溶解性的研究

采用研磨法,以聚乙二醇6000为载体,将竹红菌甲素制备为固体分散体,增加其在水溶液中的溶解度,提高其生物利用度。采用紫外-可见分光光度计和荧光分光光度计分别测定竹红菌甲素-聚乙二醇6000固体分散体的吸光度和荧光强度。通过正交试验设计的方差分析,得到该固体分散体的最优制备条件：药物和载体的比例（mg·mg-1）为1：1...     

不同因素对包膜尿素材料有机物分解的影响

在不同温度、水分等条件下,将有机物料进行发酵培养,培养7 d后检测其水溶性有机质/氮含量。结果表明:微生物G对物料中有机氮的分解比微生物H的分解能力强,微生物H对物料中有机质的分解比微生物G的分解能力强。当激活剂添加量为0.33%、水分含量为80%、温度为30℃时,微生物G的活性最高,物料J在微生物G的作用下,其水溶性有机质和水溶性有机氮含量均达到最大值,发酵效果最好。     

Effect of pH on Potentially Toxic Trace Elements (Cd,Cu, Ni,and Zn) Solubility in Two Native and Spiked Calcareous Soils: Experimental and Modeling

The effect of soil pH on solubility of the potentially toxic trace elements (PTEs) [cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn)] was assessed using two native and spiked calcareous soils. Multiple PTEs solutions were added to soils and equilibrated (aged) for 40 days. Then, PTEs solubility was measured at different pH level (1–3 units below and above the pH of native soils). In native soils, all PTEs displayed a V-shaped pH-dependent solubility pattern with important releases at pH 4 and 10 (native soil 1) and 5 and 11 (native soil 2). In spiked soils, the general tendency for the pH where solubility started was in the order Cd > Ni > Zn > Cu. Solubility of added trace elements increased with a decrease in pH. Solubility of PTEs occurred at a lower pH in the soil with a higher carbonate content than the other soil (both native and spiked). In order to predict the effect of soil pH on solubility of PTEs, surface complexation and ions exchange models of PHREEQC program were used. The model simulated the PTEs solubility in soils very well. Comparison of experimental and simulated data indicated that ions exchange and surface complexation were the main mechanisms for predicting PTEs solubility in soils. Environmental implications concerning PTEs mobility might be derived from these findings.     

Stimulation in the movement and uptake of phosphorus in response to magnetic P solution and arbuscular mycorrhizal fungi in Ocimum basilicum

A greenhouse experiment was conducted to assess the effects of magnetic field, arbuscular mycorrhizal fungi (AMF), and phosphorus (P) concentration in the nutrient solution (0, 5, 10, 20, or 40 mg L^?1) on the mobility and accumulation of P in soil and plant tissues of basil (Ocimum basilicum L.). The experiment was designed as a factorial combination and treatments were arranged in a completely randomized design with four replicates. Magnetic field increased water-soluble P in the soil and P concentration in plant shoot by 30.0% and 13.0%, respectively, in comparison to the control. The application of magnetic field and inoculation of AMF at 10 mg P L^?1 increased the P translocation efficiency by 23.3% and 17.8%, respectively. Overall, our results demonstrated that the use of magnetic field and AMF could be an effective tool for enhancing of uptake and movement efficiency of P even at low concentrations.     

N,O-羧甲基壳聚糖抗菌染料的制备研究

以壳聚糖(CTS)和活性艳蓝KN-R染料为原材料,通过两步反应法制备新型N,O-羧甲基壳聚糖染料,用红外光谱(FTIR)、X射线衍射(XRD)、元素分析仪分析其结构和化学基团,并用紫外可见分光光度计对其水溶性进行检测;采用常压浸渍法制备N,O-羧甲基壳聚糖染料染色薄木,用光谱光度仪进行表面颜色及日晒和水洗色差测量;用菌落计数法定量表征其抗菌性能。结果表明:CTS分子中大量—OH、少量—NH2基团被—CH2COOH基团取代,染料中的—SO-3和N,O-羧甲基壳聚糖中质子化的—NH+3发生反应;羧甲基化和染料接枝反应使得CTS结晶度下降;N,O-羧甲基壳聚糖染料的水溶性得到显著改善;N,O-羧甲基壳聚糖染料可明显改善薄木的染色效果,且染色薄木的耐日晒和耐水洗牢度均提高;N,O-羧甲基壳聚糖染料染色薄木的抗菌性能优于活性艳蓝KN-R染色薄木。      

Relationship between water soluble and exchangeable soil cations for estimating plant uptake and leaching potential

Abstract

The relationship between water soluble and exchangeable cations (Ca, Mg, Na, and K) was investigated for surface horizons of 195 soils including many taxonomic categories and a wide range in physical and chemical properties from around the world. This will provide information on exchangeable soil cation solubility for use in estimating plant uptake and leaching potential. Amounts of water soluble and exchangeable cations were not consistently related (r² of 0.50, 0.08, 0.77, and 0.49 for Ca, Mg, Na, and K). High correlations were biased by high water soluble and exchangeable cation levels of a few soils that had 3.8‐ and 2.5‐fold greater mean than median values. The ratio of exchangeable to water soluble cations was closely related to cation saturation (r² of 0.87, 0.95, 0.95, and 0.93 for Ca, Mg, Na, and K, respectively). As the degree of saturation of the exchange complex by a certain cation increased, solubility Increased. A change in saturation had less effect on K than on Na, Mg, and Ca solubility. Only exchangeable soil cations (NH₄OAc extractable) are routinely measured and reported in soil survey reports, thus, water soluble levels may be determined from cation saturation. This will allow estimation of the amounts of cation that can potentially move in solution through the soil or be taken up by plants. Use of cation saturation, in addition to exchangeable content, will better characterize soil cation availability by representing quantity, intensity, and buffer factors.