Optimization of Process Parameters for Removal of Arsenic Using Activated Carbon-Based Iron-Containing Adsorbents by Response Surface Methodology

Rhizoremediation is a complex type of green clean-up technology that involves both plants and the rhizosphere-associated microorganisms to decompose hazardous compounds. The success of the strategy strongly depends on plant tolerance towards the pollutant, as well as plant's interactions with the rhizospheric microbes. The microorganisms may be stimulated by the secreted root exudates, which results in an increased breakdown of contaminants in the rhizosphere. The main goal of this study was to establish a potential rhizoremediation combination for a diesel-polluted site. Inoculation of plant roots or seeds with indigenous rhizospheric populations is a common approach in the rhizoremediation. However, we introduced hydrocarbon-degrading consortia (M10, R3, and K52) that were previously isolated from crude oil-contaminated soil instead of indigenous microbes. Bioaugmentation with these petroleum degraders was applied to screen four high biomass crop species (Indian mustard, alfalfa, high erucic acid rapeseed, HEAR, and low erucic acid rapeseed, LEAR) for their tolerance towards diesel oil. At no pollution, a promoting effect of M10 bacteria could be observed on germination and root elongation of all plant species. Moreover, M10 consortiums increased the germination index at 6,000 mg diesel oil per kilogram dry soil in the case of Indian mustard, alfalfa, and HEAR. The latter species was found to increment its dry weight upon bioaugmentation with M10 bacteria and all diesel oil treatments (6,000 and 24,000 mg diesel oil per kilogram dry soil). The initial results indicate HEAR and the M10 bacterial consortium as a promising plant–microbe tandem for a long-term rhizoremediation process.

     

响应面优化鲜切猕猴桃片微波处理工艺

为探究微波处理鲜切猕猴桃片的最佳工艺条件,本研究以猕猴桃片的失重率、硬度、色差(ΔE)、可滴定酸(TA)含量、抗坏血酸(Vc)含量、可溶性糖含量、可溶性固形物(TSS)含量、糖酸比、总酚含量、叶绿素含量及菌落总数为响应值,考察微波功率、微波时间、切片厚度3个因素及其交互作用对猕猴桃片品质的影响,通过主成分分析法和Box...     

Ultrafiltration of Aqueous PVA Using Spinning Basket Membrane Module

The performance of spinning basket membrane (SBM) module was tested for the separation of polyvinyl alcohol (PVA) from wastewater. The SBM performance was examined using 50 kDa polyethersulfone ultrafiltration membrane under different parametric conditions. Also, the effects of rotational speed and transmembrane pressure on permeate flux and PVA rejection were investigated. The rotational speed played a significant role in decreasing membrane fouling by reducing the particle deposition on the membrane surface due to enhanced turbulence and shear force. Also, the in-built hydrodynamic cleaning facility of the SBM module allowed easy cleaning of the membrane. The steady-state value of percentage rejection of PVA was above 90% when the steady-state permeate flux value was above 54% of its initial value. The results suggested that spinning basket membrane module was efficient as well as economical for the separation of PVA from aqueous solution.     

Mixograph Absorption Determination by Response Surface Methodology

The advantages of using the mixograph to determine dough mixing properties include minimal flour requirements (2–35 g) and an efficient mixing process that rapidly resolves mixing peaks. A disadvantage to using this instrument is that it lacks an objective absorption measurement. This article describes an analysis system, RsMix, that objectively determines water absorption and statistically evaluates (R² and probability values) this measurement. The RsMix system also exports files that produce response surface plots. These plots illustrate the response of the dough to different combinations of mixing time and absorption. Each data set analyzed by the RsMix system was composed of an absorption series run at 2% absorption increments. The RsMix system attempts to maximize power input over data collected over absorption and time ranges. These data can be input manually or automatically acquired from MixSmart data files. To measure the precision of the RsMix system, a replicated absorption series composed of four to six different amounts of added water was analyzed. Depending on the mixer and formulation used, calculated standard deviations for optimum absorptions ranged from 0.8 to 2.0%. A regression comparing flour protein content to 2-g mixograph absorption had r² = 0.80. A similar regression comparing 2-g mixograph to 50-g farinograph absorption had r² = 0.81. Mixograph parameters could also account for 90% or more of the variation in bake absorption, bread volume, and total bread scores.     

COD Reduction in Semiconductor Wastewater by Natural and Commercialized Coagulants Using Response Surface Methodology

Pollution due to ashes spilt out into forest roads has been identified. This source influences the analytes concentrations in soil in their close vicinity. The anomaly was discovered during the biomonitoring tests conducted in the area of Bory Stobrawskie (southern Poland). Samples of Pleurozium schreberi moss and soil collected near the road showed higher values of macro- and microelements in comparison with other samples collected within the monitored area. A total of 41 elements was determined: 38 using instrumental neutron activation analysis (INAA) and 3 using atomic absorption spectrometry (AAS). It has been demonstrated that the analytes concentration in ashes is several to a dozen or so times even higher than mean concentrations determined in soil samples collected at a distance of 5 to 30 km from the road (pollution source). In mosses growing near the road covered with ash, increased concentration of the following elements has been determined: Mg, Al, Cl, Ca, Sc, V, Mn, Fe, Zn, As, Se, Br, Cd, I, La, Dy, Yb, Ta and Th, which could gives evidence to the presence of bioavailable forms of these elements. This anomaly could lead to erroneous assessment of deposition of pollutants created by emitters long apart.     

Fluoride Removal from Water Using Combined Moringa oleifera/Ultrafiltration Process

The occurrence of fluoride in groundwater has been reported in many countries, mainly because the excess fluoride in drinking water can lead to dental or skeletal fluorosis. Fluoride removal by coagulation with Moringa oleifera seeds, followed by separation with membranes, was investigated in this work. Artificially fluoridated water, at a starting fluoride concentration of 10?mg?L^?1, was submitted to a coagulation process with aqueous extracts of M. oleifera seeds. The coagulation process was followed by ultrafiltration with membranes at different pressures. The coagulation process with 2.5?g?L^?1 of M. oleifera promoted a reduction of 90.90?% in the fluoride content of the treated water, making it possible for poor communities to consume this water. It is noteworthy that the combined coagulation/filtration process using raw coagulant showed the highest values of colour and turbidity, which, however, were still below the limits set for drinking water by Brazilian legislation. The advantage of proposing a sequential process using membrane separation is that it removes colour and turbidity, caused by the use of M. oleifera as a coagulant, resulting in water that meets potability standards.     

响应面法优化制备高富硒产朊假丝酵母

考察了发酵条件对产朊假丝酵母富硒能力的影响。通过单因素的筛选,对酵母富硒能力影响较大的3个因素:亚硒酸钠浓度、初始p H值及培养温度,以胞内总硒含量为响应值,利用响应面法对其进行优化。结果显示:在培养时间30 h、加硒时间对数生长中期、亚硒酸钠浓度35 mg·L-1,初始p H 6.6、接种量10%、培养温度27℃、装液量150 m L/500 m L的条件下,最大的菌体生物量为6.87 g·L-1;胞内总硒含量达到12 639.7μg·L-1,硒含量为1 839.8μg·g-1,其中亚硒酸钠转化率为79.1%,有机硒含量占90%以上;胞内实际总硒含量与数学模型理论值12 518.8μg·L-1相差不显著,响应面法能较好地优化产朊假丝酵母富硒工艺条件。     

Estimation of the Effects of Maize Straw Return on Soil Carbon and Nutrients Using Response Surface Methodology

Straw incorporation is generally considered an effective agricultural management practice that improves nutrient cycling and maintains soil fertility. To study the interactive effects of straw returning factors on soil organic carbon and available nutrients, a17-month(May 6, 2016 to October 6, 2017) experiment was conducted on straw incorporation by using response surface methodology under a three-factor(straw length, amount, and burying depth), five-level quadratic orthogonal rotation experimental design. Weight was assigned to each indicator for soil carbon and nutrients and then a comprehensive indicator was established. Then, a second-order polynomial model of the three straw returning factors was established using response surface methodology. Results indicated that17 months after straw incorporation, straw amount and burying depth had significant effects on the comprehensive indicator of soil carbon and nutrients. Straw length and the interactions of straw amount and burying depth showed no significant effects on the comprehensive indicator of soil carbon and nutrients. It was concluded that 17 months after straw incorporation, the highest value of the comprehensive indicator of soil carbon and nutrients was achieved when the straw length, amount, and burying depth were approximately 17–20 cm, 740–840 g m~(-2), and 9–13 cm, respectively, which can be recommended as the most suitable parameters for use in straw returning in the study area.     

黑曲霉固体发酵产木聚糖酶的响应面优化设计及其酶学性质的研究

本研究采用响应面法的中心组合对影响黑曲霉(aspergillus niger JL 15)固体发酵产木聚糖酶的条件进行了优化.以橘皮粉为基质,补充碳源、氮源,以及含水量和发酵时间对木聚糖酶产量具有显著影响(P<0.05).模拟二次多项式回归预测模型,并建立自变量与响应值的回归方程,获得各因素的最佳水平,即:甘油、硫酸铵的添加量分别为4.2%和3.1%,含水量为61%,发酵时间为73.4 h,木聚糖酶活性最大预测值达922.9 U/g干发酵产物,验证值为917.7 U/g干发酵产物,高出基础培养基酶活3.2倍.酶学性质分析研究表明,黑曲霉木聚糖酶(XylA)的最适温度和最适pH分别为55oC和pH 5.0.XylA的K_m和V_(max)值分别为9.24 mg/mL和54.05 μmol/min/mL.Mn~(2+)、Zn~(2+)和斗和Mg~(2+)对XylA活性具有促进作用,而Fe~(3+)和cu~(2+)对XylA活性具有明显抑制作用.HPLC分析结果表明,XylA的水解桦木木聚糖和麸皮不溶性木聚糖的产物均为木糖至木六糖,主要产物为木三糖.     

Optimization of Cu(II) Extraction from Aqueous Solutions by Soybean-Oil-Based Organic Solvent Using Response Surface Methodology

This study aimed to optimize two process variables, namely extractant concentration, i.e., di-2-ethylhexylphosphoric acid concentration ([D2EHPA]) and equilibrium pH (pH_eq), in Cu(II) extraction from aqueous solutions with a soybean-oil-based organic solvent using response surface methodology by maximizing the percentage extraction (%E). A central composite design was applied, and a regression model for %E was developed. Adequacy of the model was examined, and it was found to be statistically significant. The optimum conditions were determined as follows: [D2EHPA] of 84.71?mM and pH_eq of 4.46, which resulted in 99.78% of %E. The experimental value of %E (98.17%) obtained is found to agree satisfactorily with that (99.78%) predicted from the model.     

利用响应面法优化石榴酒发酵工艺条件

攀枝花的石榴品种繁多,籽粒味甜汁多,为了充分利用这一优势资源,本文进行石榴酒发酵,并对其发酵工艺利用响应面分析法进行优化。以酒精度为指标,考虑发酵温度、二氧化硫添加量、酵母接种量对石榴酒发酵酒精度的影响,然后根据中心组合030x—Benhnken）原理采用三因素三水平的分析法,依据回归确定各工艺条件的影响因素,以石榴酒发酵酒精度为响应面和等高线,分析各个因素的显著性和交互作用,结果表明优化得到石榴酒发酵的最佳工艺条件为二氧化硫添加量51．3mg／kg,酵母菌接种量5．33％,发酵温度24．98℃,酒酒精度的理论值为9．58％。通过响应面分析优化发酵工艺,为今后石榴酒发酵的更进一步开发提供一定的理论依据。     

Removal of Nickel by Means of Micellar-Enhanced Ultrafiltration (MEUF) Using Two Anionic Surfactants

Micellar-enhanced ultrafiltration (MEUF) is an effective separation technique for removing metal ions from aqueous environments. The critical micellar concentration (CMC) of two anionic surfactants, sodium dodecyl sulfate (SDS) and linear alkylbenzene sulfonate (LAS), was determined by means of conductometry. The effects of pH, conductivity, and surfactant concentration on the permeate flow, retention of surfactants and nickel by MEUF, was studied. Results showed that for surfactant concentrations beyond the CMC, Ni(II) retention with SDS was slightly higher than with LAS (S/M?=?45: Ni(II) retention was 70% and 55% for SDS and LAS, respectively). LAS surfactant was always retained in higher quantities than SDS. An increase in conductivity produced large reduction in Ni(II) retention and slightly increased surfactant retention. pH values between 4 and 8 did not affect nickel retention but enhanced the SDS and LAS surfactant retentions.     

3种水生植物组合对双酚A胁迫的响应

为了探究植物组合内各种植物对双酚A(bisphenol A,BPA)的生理生化响应机制,及植物组合较单一植物在植物修复双酚A中的优势,本试验以湿地植物芦苇(Phragmites australis)、香蒲(Typha orientalis)和荻(Triarrhena sacchariflora)为材料,研究了 3种植物...     

Evaluation of the Removal of Pollutants from Petrochemical Wastewater Using A Membrane Bioreactor Treatment Plant

Water, Air, & Soil Pollution - A submerged membrane bioreactor (MBR) was used to treat two types of petrochemical wastewater: olefin process wastewater and total petrochemical wastewater....