Removal of ochratoxin A in red wines by means of adsorption treatments with commercial fining agents

The presence in wine of the fungal metabolite, ochratoxin A (OTA), represents a serious risk for consumer health. A variety of fining agents, including activated carbon, silica gel, potassium caseinate, egg albumin, and gelatin, was evaluated in relation to their abilities to remove OTA in fortified wines. Freundlich adsorption isotherms were used to model the adsorption behavior between ochratoxin A and the fining agent. Potassium caseinate and activated carbon were found to be the best fining agents that could be used to remove OTA in wine. Potassium caseinate removed up to 82% of OTA when used at 150 g/hL, whereas activated carbon showed the highest specific adsorption capacity due to a high surface area per mass and low adsorption of total polyphenols.     

Removal of Copper and Cadmium Ions from Diluted Aqueous Solutions by Low Cost and Waste Material Adsorbents

The sorption of copper and cadmium ions using activated carbon,kaolin, bentonite, diatomite and waste materials such as compost,cellulose pulp waste and anaerobic sludge as sorbents is reported. Equilibrium isotherms were obtained for the adsorption of these metals in single and binary solutions. Bentonite presented the highest adsorption capacities for both copper and cadmium. A competitive uptake was observed when both metals are present; copper being preferentially adsorbed by all materials with theexception of anaerobic sludge. Equilibrium data were fitted toLangmuir and Freundlich models, with satisfactory results for most of the adsorbent-metal systems studied.Of all the adsorbents studied, bentonite and compost presentedthe highest removal efficiencies, reaching 99% for copper whencadmium is also present, for initial solution concentrations ofup to 100 mg L^-1. Anaerobic sludge has a greater preferencefor cadmium, even in the presence of copper, with removal efficiencies of 98% for similar concentrations to those mentioned above.     

Removal of Ammonia from Aqueous Solutions,Ground Water,and Wastewater Using Mechanically Activated Clinoptilolite and Synthetic Zeolite-A: Kinetic and Equilibrium Studies

Natural zeolite clinoptilolite and synthetic zeolite Na-A were characterized using XRD and SEM to be used as adsorbents for ammonia from aqueous solutions, ground water, and sewage water. Clinoptilolite was mechanically activated for 2, 4, 6, and 8 h to study the effect of activation in enhancing the adsorption capacity. The adsorption by activated natural zeolite and synthetic zeolite is high pH dependent and achieve the best values at pH?=?7. The adsorption capacity of activated natural zeolite increases with increasing the activation from 2 to 8 h achieving removal percentage close to that obtained using synthetic zeolite. The equilibrium was obtained after 60 min for synthetic zeolite and all the activated natural zeolite (except 2-h-activated product, the equilibrium was achieved after 30 min). The kinetic studies reflected the high fitness of the adsorption results of activated natural zeolite products and synthetic zeolite with pseudo-second-order model rather than the other kinetic models. The obtained isotherms reflected the formation of S-type isotherm curve for the adsorption using mechanically activated clinoptilolite and L-type curve for the uptake using synthetic zeolite. The results represented well with Langmuir model followed by Temkin and Freundlich model for adsorption using synthetic zeolite. The uptake using mechanically activated clinoptilolite can be represented by Temkin model rather than both Langmuir and Freundlich models. Thermodynamic parameters indicate spontaneous endothermic adsorption of ammonia using all the zeolitic products under investigation. Finally, the mechanically activated natural zeolite and synthetic zeolite exhibit high efficiency in the removal of ammonia and other water pollutants from ground water and sewage water.     

铁铝柱撑膨润土组成特征及其磷吸附性能研究

利用天然膨润土合成了铁柱撑膨润土（Fe1-Mt、Fe10-M）t、羟基铁膨润土（FeOx-M）t、羟基铝膨润土（AlOx-M）t和羟基铝铁膨润土复合体（AlFe-M）t,对其化学组成和矿物组成等特征进行分析,比较了5种不同铁铝柱撑膨润土对磷污染水体的吸附净化性能,并通过等温吸附试验探讨了柱撑膨润土对磷的吸附机制。结果发现,不同铁铝柱撑均可以增加天然膨润土的层间距,其中以羟基铝铁膨润土复合体的层间距增加最明显,与原土相比增加约为2倍。5种不同铁铝柱撑均能显著增强膨润土对磷污染水体的吸附净化能力,其中以FeOx-Mt的理论磷吸附容量最大,为12.03mg.g-1,其次为Fe10-Mt、AlFe-Mt和AlOx-Mt,吸附等温曲线同时符合Freundlich方程和Langmuir方程,均达显著水平。结果表明,除膨润土层间距外,不同铁铝柱撑膨润土的磷吸附能力主要与铁铝氧化物的含量及铁的存在形态相关。     

Effects of Municipal Sewage Sludge Application on Soil and Purple Moor-grass (Molinia caerulea) Contamination by Metals in a Maritime Pine Forest

Granular bentonite has been assessed regarding its capacity to remove Hg(II), Cd(II) and Pb(II) from aqueous solutions. Sorption capacities, kinetics and the dependence of the sorption process on pH were determined. Fractional power, pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were used to model the kinetics of metal adsorption. The pseudo-second-order model showed the best fit to experimental data. Different two-parameter sorption isotherm models (Langmuir, Freundlich, Temkin and Dubinin?CRadushkevich) were used to fit the equilibrium data. Freundlich's isotherm model gave the best fit to experimental data. The selectivity of granular bentonite towards these metals is Pb(II)?>?Cd(II)?>?Hg(II). The adsorption capacities of granular bentonite towards the metals expressed in milligramme metal per gramme granular bentonite are 19.45, 13.05 and 1.7 for Pb(II), Cd(II) and Hg(II), respectively (for an initial concentration of 100 mg metal/L).     

天然膨润土的矿物特性及其磷吸附性能研究

比较了不同天然膨润土共7个样品对不同程度磷污染水体的吸附净化性能,通过等温吸附实验,探讨了膨润土对磷的吸附机制.结果发现,供试膨润土对水体磷均有一定的吸附净化潜力,但针对不同程度磷污染水体存在一定差异,且同一属型膨润土的吸附净化能力因矿物组成差异而不同.针对模拟V类水(P 0.4 mg/L)和劣V类水(P 1.0 mg/L),BN-2的吸附净化能力最强,BN-6的吸附净化能力较差,而其余膨润土对磷的吸附净化能力稍显差异.天然膨润土对磷的吸附等温曲线符合Freundlich方程,说明膨润土对磷的吸附可能属于不均匀介质的多分子层吸附.结果表明,在针对不同程度磷污染水体时,需根据膨润土的矿物特性,使各具特殊性质的不同天然膨润土矿样得到有效的应用.     

Preparation, Characterization, and Environmental Application of Crosslinked Chitosan-Coated Bentonite for Tartrazine Adsorption from Aqueous Solutions

The preparation, characterization, and environmental application of crosslinked chitosan-coated bentonite (CCB) beads for tartrazine adsorption have been investigated. CCB beads were characterized by using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) surface area and Barrett–Joyner–Halenda (BJH) pore size distribution analyses were also determined. The values of pH of the aqueous slurry and pH of zero point charge (pH_ZPC) were almost equal. The adsorption at equilibrium of tartrazine was found to be a function of pH of the solution, stirring rate, contact time, and tartrazine concentration. The optimum conditions for tartrazine adsorption were pH 2.5, stirring rate of 400 rpm and contact time of 80 min. Pseudo-first-order and pseudo-second-order models were used to analyze the kinetics of adsorption with the latter found to agree well with the kinetics data, suggesting that the rate determining step may be chemisorption. The two most common isotherm models, Langmuir and Freundlich, were used to describe the adsorption equilibrium data. On the basis of Langmuir isotherm model, the maximum adsorption capacities were determined to be 250.0, 277.8, and 294.1 mg g^?1 at 300, 310, and 320 K, respectively. Desorption studies were carried out at different concentrations of EDTA, H₂SO₄, and NaOH. All desorbing solutions showed poor recovery of tartrazine.     

锑/磷在膨润土和高岭土的竞争吸附

采用批处理法研究了锑/磷(Sb/P)在膨润土和高岭土上的竞争吸附等温线和动力学,并考察了pH的影响。结果表明:Sb和P吸附符合Langmuir或Freundlich方程(R~2=0.945 0~0.998 3,P0.000 1),存在极强的竞争吸附:P共存时Sb吸附容量(Q_(max))显著降低,分别从0.86和10.21 mmol/kg(先Sb后P)降低到0.64和2.61 mmol/kg(先P后Sb);Sb共存时P吸附亲合性(K)明显降低,分别从1.47和7.47 L/mmol(先P后Sb)降低到0.68和2.34 L/mmol(先Sb后P)。Sb和P的吸附总体随pH升高而降低,但相比高岭土,膨润土上的吸附受pH影响更大,意味着高岭土有更多配位吸附、膨润土有更多电性吸附。准二级动力学方程很好地拟合它们的竞争吸附(R~20.994,P0.000 1),并且在Sb/P共存下,膨润土对P吸附弱而慢(q_e=0.36 mmol/kg,,k_2=0.064 6 kg/(mmol·min))、对Sb吸附虽弱但快(q_e=0.19 mmol/kg,k_2=0.076 9 kg/(mmol·min));高岭土对P吸附强更快(q_e=0.66 mmol/kg,k_2=0.591 kg/(mmol·min))、对Sb吸附虽强但慢[q_e=0.39 mmol/kg,k_2=0.052 4 kg/(mmol·min)]。因此,Sb对P吸附的抑制在膨润土上更明显(主要是静电吸附竞争),P对Sb吸附的抑制则在高岭土上更突出(主要是配位吸附竞争)。     

Comparison of Surface-Modified Adsorbents for Phosphate Removal in Water

Three novel composite adsorbents, sulfate-coated zeolite (SCZ), hydrotalcite (SCH), and activated alumina (SCAA), were characterized and employed for the removal of phosphate from aqueous solution using equilibrium and kinetic batch experiments. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction spectrum were used to study the surface characteristics of the coated layer. Equilibrium tests showed that the adsorption of phosphate followed both Langmuir and Freundlich isotherms. The powder-type SCZ was better for phosphate removal (maximum binding energy, ???=?111.49?mg?g^?1) compared to hydrotalcite and activated alumina. The adsorption of phosphate was considered to take place mainly by ion exchange. The kinetic data followed a pseudo-second-order kinetic model. The initial adsorption of phosphate onto the sulfate-coated adsorbents was fast, indicating that the sulfate-coated materials developed in this study can be used as promising adsorbents for the removal of phosphate from wastewater or sewage.     

Equilibrium studies for the adsorption of dyestuffs from aqueous solutions by low-cost materials

A number of low-cost materials (teakwood bark, ricehusk, coal, bentonite clay, hair and cotton waste) have been used as adsorbents for dyestuffs in aqueous solutions. Four red and four blue dyes have been studied; each color group consisted of an acidic, a basic, a disperse and a direct dye. The equilibrium isotherm for each dye-adsorbent system was determined and adsorption capacities from zero to 200 mg dye g^?1 of adsorbent was obtained. In general basic dyes adsorbed to a greater extent than the other dye classes but no single characteristic of the dye or adsorbent seemed responsible for such dye-adsorbent interactions and adsorption capacities.     

几种吸附剂对阿特拉津的吸附及其 Zeta 电位特性研究

通过振荡吸附平衡试验,研究了蒙脱石、凹凸棒石、竹炭、木炭对阿特拉津的吸附行为,讨论了pH值、离子强度对吸附的影响,并考察了吸附剂表面的Zeta电位变化。结果表明,几种吸附剂对阿特拉津的吸附均符合Freundlich方程;竹炭、木炭的吸附能力明显高于蒙脱石和凹凸棒石。吸附剂对阿特拉津的吸附量随着悬液离子强度的增加而增加,在悬液pH一定(pH=6),离子强度为10-3mol/L NaNO3时,蒙脱石、凹凸棒石对阿特拉津的吸附量分别为538.30、609.68 mg/kg,当离子强度增加为10-2mol/L时,吸附量分别增至611.26、731.63 mg/kg;当离子强度由10-3增至10-1mol/L NaNO3时,竹炭、木炭对阿特拉津的吸附量有较多增加。当悬液pH在3~8范围时,几种吸附剂表面均带负电荷,其Zeta电位值随着pH的增加而增加,随离子强度的增加而减小。悬液离子强度一定时,随着pH的增加,吸附阿特拉津后吸附剂表面Zeta电位变化不显著。研究结果有助于从机理上解析吸附剂对有机污染物的吸附行为。     

改性高岭土对废水中磷的吸附性能及机理研究

采用盐酸和煅烧2种方法对苏州高岭土进行了改性,分析其对模拟含磷废水中磷的吸附效果,并初步探讨了其作用机制,继而进行了等温吸附和吸附动力学试验研究。结果显示,酸、热改性均不同程度地提高了高岭土对模拟废水中磷的吸附净化能力,尤以9%酸改性和500℃煅烧效果最为明显。在处理25 ml浓度为20 mg/L的模拟含磷废水中,高岭土投加量为2%(重量比)时,经9%酸改性高岭土对磷去除率达81.8%,较天然高岭土提高了44.6%。在处理50 ml浓度为20 mg/L的模拟含磷废水时,经500℃煅烧改性高岭土对磷的去除率高达99.5%,残留溶液中磷浓度仅为0.10 mg/L,达到我国相应排放标准。酸改性可通过改变高岭土的吸附活性点位来提高其对磷的吸附净化性能,而煅烧通过活化高岭石中的铝而提高其对磷的吸附净化性能。天然、9%酸改性及500℃煅烧高岭土磷吸附等温线均符合Freundilch和Langmuir方程,皆达极显著水平(P<0.01)。天然、9%酸改性及500℃煅烧高岭土对磷的动力学吸附特征一致,皆与准二级方程拟合最佳,达极显著水平(P<0.01)。500℃煅烧高岭土对磷的饱和吸附量最大,在净化含磷废水中具有良好的应用前景。     

Models for tetracycline in aquatic environments

The interactions of tetracycline with model clay adsorbents has been studied as a function of suspension pH, ionic strength, and adsorbate concentration. The model clay adsorbents were the Na, Ca, and dodecyltrimethylammonium forms of bentonite and a tannic acid covered bentonite. The adsorption isotherms were of the Langmuir type and the adsorption capacity decreases in the order tannic acid-clay > Ca-clay > Na-clay > dodecyltrimethylammonium-clay. The adsorption onto the clay substrates decreases as the ionic strength and pH increases.     

Residual Organic Compound Removal from Aqueous Solution Using Commercial Coconut Shell Activated Carbon Modified by a Mixture of Seven Metal Salts

The modified activated carbon (MAC) derived from commercial coconut shell activated carbon (AC) with mixture of seven metal salts was used as an adsorbent to remove target residual organic compound (sucrose) from aqueous solutions in batch modes. The results indicated that the highest adsorption capacity of sucrose onto MAC reached when the AC was modified at the ratio of impregnation of AC with mixture of seven metal salts, including nitrate silver (AgNO₃), manganese nitrate (Mn (NO₃)₂), potassium bichromate (K₂Cr₂O₇), nitrate cobalt (Co (NO₃)₂·6H₂O), nitrate copper (Cu (NO₃)₂·3H₂O), nitrate nickel (Ni (NO₃)₂·6H₂O) and nitrate iron (Fe (NO₃)₂·9H₂O) of 3% (w/w). The most appropriate conditions for sucrose adsorption onto MAC in batch experiments obtained at pH 7, contact time of 120 min, 800 mg MAC/50 mL of sucrose solution with initial concentration of 1500 mg/L. At this condition, the highest adsorption capacity of sucrose onto MAC reached 28.28 mg/g. The Langmuir, Freundlich, and Sips adsorption isothermal equilibrium models can adequately describe the adsorption properties of sucrose on MAC. The adsorption kinetic of sucrose onto MAC obeyed pseudo-first-order and pseudo-second-order models with the chemical sorption process. The saturated MAC was recovered by heat from an oven. The highest recovery efficiency of saturated MAC obtained at 180 °C in 120 min. The highest adsorption capacity of sucrose onto recovered MAC was 24.31 mg/g, appropriately adsorption capacity of initial MAC.     

Removal of Cu2+ and Cd2+ from Aqueous Solution by Bentonite Clay Modified with Binary Mixture of Goethite and Humic Acid

Pre-modification of bentonite clay with goethite, humic acid, and a binary mixture of goethite and humic acid reagents increased its cation exchange capacity from 95 to 105.32, 120.4, and 125.8 meq/100 g of bentonite clay, respectively. The effective pre-modification of bentonite clay with goethite, humic acid, and goethite–humic acid reagents was confirmed from their Fourier transform infrared spectra which suggested that modification was effective on the AlAlOH and Si–O sites for goethite and humic acid modification and AlAlOH for goethite–humic acid modification. The presence of 0.001 M NaNO₃ electrolyte increased the adsorption capacity of bentonite clay. Temperature was observed to favor the adsorption of Cu²⁺ and Cd²⁺ onto both the raw and modified bentonite clay samples. The goethite–humic acid-modified bentonite gave the best adsorption capacity of ≈10 and 16 mg/g at 30 and 50°C, respectively, for both metal ions. The inner sphere complexation mechanism was suggested for the adsorption of both metal ions onto the modified adsorbents. Modifying bentonite clay with a binary mixture of goethite and humic acid reduced the selectivity of bentonite clay for either Cu²⁺ or Cd²⁺. Preadsorbed goethite and humic acid on bentonite clay will further reduce the mobility of heavy metal ions in soils and in aquatic environments.     

褐煤基材料对Cd~(2+)的吸附机制

为筛选稳定、高效、环境友好的重金属污染修复材料,利用批吸附试验研究了不同温度下褐煤、腐植酸、活性炭对镉(Cd~(2+))的吸附特征,采用非线性χ~2检验辅助决定系数判断等温线模型拟合度,用红外光谱对材料功能团进行了识别。结果表明,Temkin模型能最好拟合3种材料对Cd~(2+)的等温吸附过程,Langmuir和Freundlich模型也能较好拟合但与温度有关。吸附热力学参数表明,3种材料对Cd~(2+)的吸附为优惠发生的物理吸附,并且是自发的吸热过程,3种材料与Cd~(2+)之间均有较强的作用力。在温度294.55~313.15 K时腐植酸、褐煤和活性炭对Cd~(2+)的最大吸附量分别为36.14~44.09、29.63~38.20 mg·g~(-1)和21.04~30.34 mg·g~(-1),吸附量随温度升高而升高,吸附自由能随着温度升高而降低,说明升温吸附更容易发生。准二级动力学拟合数据最好,表明3种材料对Cd~(2+)的吸附存在着化学过程。褐煤基活性炭和褐煤基腐植酸具有丰富的孔隙结构。红外光谱图表明腐植酸和褐煤较大的吸附量与其含氧功能团种类较多以及在波数2 360 cm~(-1)和2 342 cm~(-1)附近吸收峰有关。因此,褐煤基3种材料对Cd~(2+)的吸附是自发的吸热过程,腐植酸对Cd~(2+)的最大吸附量和吸附能力最大,用Temkin等温方程和准二级动力学曲线能最适宜描述褐煤基材料对Cd~(2+)的吸附特征。     

Effect of ethanol and red wine on ochratoxin a-induced experimental acute nephrotoxicity

Ochratoxin A (OTA), is a nephrotoxic mycotoxin present in wine, which is nephrotoxic in humans. Our working hypothesis is that natural substances in wine may counteract OTA toxicity. Thirty-six rats were randomized to OTA dissolved in saline, red wine, or 13.5% ethanol or to OTA-free wine, ethanol, or saline. OTA (289 microg/kg of body weight/48 h) was administered by gastric gavage for 2 weeks. Serum creatinine, tubular enzymuria, renal lipohydroperoxides (LOOH), reduced (GSH) and oxidized (GSSG) glutathione, and renal superoxide dismutase activity (SOD) were determined in renal tissue. OTA alone produced significant increases in renal lipoperoxides and significant decreases in SOD and GSH/GSSG ratio. In red wine or ethanol, OTA was less nephrotoxic, reducing oxidative damage as revealed by LOOH. In OTA-wine and OTA-ethanol groups, SOD activity was higher than in the OTA-treated one, suggesting that both ethanol and nonalcoholic fractions may preserve antioxidant reserve. GSH/GSSG ratio was significantly preserved only in the OTA-wine group and not in OTA-ethanol. Red wine may exert a protective effect against OTA nephrotoxicity by limiting oxidative damage. The ostensible protection afforded by ethanol deserves further investigation.     

Comparative study of protein stabilization in white wine using zirconia and bentonite: physicochemical and wine sensory analysis

A semi-industrial application of the continuous stabilization of white wine protein using a column packed with zirconia was studied and compared to the traditional bentonite treatment using a Macabeu white wine. Physicochemical and wine sensory properties were evaluated using a rating system and triangle tests. Continuous protein stabilization was analyzed in three residence times, and the equivalent of 300 BV of wine was used for both treatments. Wine protein content was reduced by 21%, 40%, and 42% using the continuous process with residence times of 7.5, 15, and 30 min, respectively, and by 61.4% using the bentonite treatment. The wines obtained from the packed column were protein stable up to 25, 75, and 175 BV for residence times of 7.5, 15, and 30 min, respectively. The amount of polyphenol removed was less than 10%, and similar amounts were removed from the wine regardless of residence time, while 20.6% of polyphenol was removed using bentonite. The physicochemical and sensory properties of wine treated with bentonite were similar to those of wine treated with zirconia.     

改性沸石对Cu~(2+)的吸附、解吸特性研究

通过室内分析的方法研究了天然沸石及3种改性沸石对Cu2+的吸附及解吸特性。研究结果表明:沸石、改性沸石对Cu2+的等温吸附曲线符合Langmuir方程、Freundlich方程、Temkin方程,其中Freundlich方程的拟合性最好,相关系数在0.991～0.999之间。沸石及改性沸石对Cu2+吸附量大小顺序为NH4-Z>K-Z>Mg-Z>Z。该规律与改性阳离子水合半径、离子价数密切相关。沸石及改性沸石对Cu2+离子的解吸量和解吸率大小顺序为Z>Mg-Z>K-Z>NH4-Z。该规律与沸石的孔道居留效应有关。改性沸石一方面增加了Cu2+的吸附,同时又降低了Cu2+的解吸率,因此改性沸石在农业生产实践中,特别是土壤重金属污染的治理方面具有广阔的应用前景。     

Fe–Ni Nanostructures and C/Fe–Ni Composites as Adsorbents for the Removal of a Textile Dye from Aqueous Solution

Novel adsorption materials—Fe–Ni nanostructures and C/Fe–Ni composites—with the carbonaceous material coming from sewage sludge, have been developed and evaluated to remove indigo carmine from aqueous solution. The adsorbents were characterized by transmission and scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and Brunauer–Emmett–Teller analysis. Sorption kinetics and isotherms were determined and the adsorption behaviours analysed. All adsorbents here studied have exhibited good efficiency to remove indigo carmine from aqueous solution. Pseudo-second-order kinetic and Langmuir–Freundlich isotherm models were successfully applied to the experimental data. Fe–Ni nanostructures adsorption capacity was 977.18 mg/g, followed by C/Fe–Ni 75/25% composite with 654.33 mg/g, and a lowest value, 486.41 mg/g, was obtained for C/Fe–Ni 95/5% composite. It can be suggested that the sorption mechanism of the dye is chemisorption on these heterogeneous novel, cheap and efficient functional materials. All materials provide the highest adsorption capacities in pH between 4 and 10. In addition, three sorption–desorption cycles using 30% H₂O₂ solution and distilled water were performed; sorption efficiencies of both composites (C/FeNi 75/25% and C/FeNi 95/5%) decreases in each cycle, but this behaviour is not observed for FeNi nanoscale oxides.