Consumer health risk to pesticide residues in Salvia officinalis L. and its infusions

Salvia officinalis L. is a popular herb widely used in culinary, cosmetic, and medicinal preparations, and also as an ornamental plant. Sage crops are threatened by many diseases, such as gray mold, powdery mildew, and leaf spot, by weeds, and by pests, such as aphids. Use of crop protection products may lead to presence of pesticide residues in this herb. The aim of this work was to study presence of pesticide residues in the herb, S. officinalis L., available on the retail market in Poland, to verify their compliance with the maximum residue levels (MRLs) and to assess the chronic and acute risks associated with consumption of this herb and infusions prepared from contaminated sage plants. Ninety active substances of pesticides were analyzed, including all active substances registered in Poland for protection of the sage. Five active substances were found, one fungicide – boscalid and four insecticides: chlorpyrifos, pp′-DDT, dimethoate (residue levels above MRL) and indoxacarb. The chronic and acute exposure to pesticide residues consumed with sage did not exceed 0.02% of the acceptable daily intake (ADI) and 0.1% of the acute reference dose (ARfD), respectively.     

Sorption and photodegradation of chlorpyrifos on riparian and aquatic macrophytes

Surface water bodies may become contaminated via spray drift following pesticide application. In this investigation, the photodegradation and sorption of chlorpyrifos was studied in four riparian macrophytes representative of Mediterranean flora (Phragmites australis, Iris pseudacorus, Equisetum pratense and Typha latifolia). The results of experiments with both the active ingredient and the formulation DURSBAN 48® EC confirm the ability of these species to interact with chemicals such as chlorpyrifos. The maximum sorption of chlorpyrifos at equilibrium was observed in Phragmites australis (22%). And, the maximum instantaneous sorption of chlorpyrifos was observed in the dried biomass of Phragmites australis (49%). The epicuticular waxes present on leaves influence photodegradation processes, resulting in a decrease in chlorpyrifos persistence depending on the nature of the extract. The half-life of chlorpyrifos residues in leaf waxes decreased from 34 to 99 minutes when irradiated.     

Enhanced visual detection of pesticides using gold nanoparticles

The presence of parts per billion (ppb) levels of chlorpyrifos (O,O-Diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) and malathion (S-1,2-bis(ethoxycarbonyl) ethyl O,O-dimethyl phosphorodithioate), two common pesticides found in the surface waters of developing countries, have been visually detected using gold nanoparticles. Visual detection of the presence of pesticide is possible when the color change occurring by the adsorption of pesticides on gold nanoparticles is enhanced by sodium sulfate. The method presented here is simple and there is no need of sample preparation or preconcentration. The response occurs within seconds and the color change is very clear. The detection is possible if chlorpyrifos and malathion are present up to a concentration of 20 and 100 ppb, respectively. The method shows great potential for on-site pesticide monitoring. The method is also applicable as a qualitative technique for the performance evaluation of various household water filters, which claim pesticide removal.     

Repeated batch and continuous degradation of chlorpyrifos by Pseudomonas putida

The present study was undertaken with the objective of studying repeated batch and continuous degradation of chlorpyrifos (O,O-diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) using Ca-alginate immobilized cells of Pseudomonas putida isolated from an agricultural soil, and to study the genes and enzymes involved in degradation. The study was carried out to reduce the toxicity of chlorpyrifos by degrading it to less toxic metabolites. Long-term stability of pesticide degradation was studied during repeated batch degradation of chlorpyrifos, which was carried out over a period of 50 days. Immobilized cells were able to show 65% degradation of chlorpyrifos at the end of the 50th cycle with a cell leakage of 112 × 10³ cfu mL^?1. During continuous treatment, 100% degradation was observed at 100 mL h^?1 flow rate with 2% chlorpyrifos, and with 10% concentration of chlorpyrifos 98% and 80% degradation was recorded at 20 mL h^?1 and 100 mL h^?1 flow rate respectively. The products of degradation detected by liquid chromatography–mass spectrometry analysis were 3,5,6-trichloro-2-pyridinol and chlorpyrifos oxon. Plasmid curing experiments with ethidium bromide indicated that genes responsible for the degradation of chlorpyrifos are present on the chromosome and not on the plasmid. The results of Polymerase chain reaction indicate that a ~890-bp product expected for mpd gene was present in Ps. putida. Enzymatic degradation studies indicated that the enzymes involved in the degradation of chlorpyrifos are membrane-bound. The study indicates that immobilized cells of Ps. putida have the potential to be used in bioremediation of water contaminated with chlorpyrifos.     

Residues of carbosulfan and its metabolites carbofuran and 3-hydroxy carbofuran in rice field ecosystem in China

The fate of carbosulfan (seed treatment dry powder) was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of carbosulfan, carbofuran, and 3-hydroxyl carbofuran in brown rice, rice straw, paddy water, and soil. The target compounds were extracted using acetonitrile or dichloromethane, cleaned up on acidic alumina or florisil solid phase extraction (SPE) cartridge, and analyzed by gas chromatography. The average recoveries of carbosulfan, carbofuran and 3-hydroxy carbofuran in brown rice, rice straw, paddy water, and soil ranged from 72.71% to 105.07%, with relative standard deviations of 2.00–8.80%. The limits of quantitation (LOQs) of carbosulfan, carbofuran and 3-hydroxy carbofuran in the samples (brown rice, rice straw, paddy water and soil) were 0.011, 0.0091, 0.014, 0.010 mg kg^?1, 0.016, 0.019, 0.025, 0.013 mg kg^?1, and 0.031, 0.039, 0.035, 0.036 mg kg^?1, respectively. The trials results showed that the half-lives of carbosulfan, carbofuran and 3-hydroxy carbofuran in rice straw were 4.0, 2.6 days, 3.9, 6.0 days, and 5.8, 7.0 days in Zhejiang and Hunan, respectively. Carbosulfan, carbofuran and 3-hydroxy carbofuran were detected in soils. Carbosulfan and 3-hydroxy carbofuran were almost undetectable in paddy water. Carbofuran was detected in paddy water. The final residues of carbosulfan, carbofuran and 3-hydroxy carbofuran in brown rice were lower than 0.05 mg kg^?1, which were lower than 0.5 mg kg^?1 (MRL of carbosulfan) or 0.1 mg kg^?1 (MRL of carbofuran). Therefore, a dosage of 420 g active ingredient per 100 kg seed was recommended, which could be considered as safe to human beings and animals. These would contribute to provide the scientific basis of using this insecticide.     

Residues of chlorantraniliprole in rice field ecosystem

The fate of chlorantraniliprole was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of chlorantraniliprole in soil, rice straw, paddy water and brown rice. Chlorantraniliprole residues were extracted from samples with acetonitrile. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, and determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The average recoveries were 76.9-82.4% from soil, 83.6-89.3% from rice straw, 95.2-103.1% from paddy water and 84.9-87.7% from brown rice. The relative standard deviation was less than 15%. The limits of detection (LODs) of chlorantraniliprole calculated as a sample concentration (S/N ratio of 3) were 0.012 μg L(-1) for paddy water, 0.15 μg kg(-1) for soil, brown rice and rice straw. The results of the kinetics study of chlorantraniliprole residue showed that chlorantraniliprole degradation in soil, water and rice straw coincided with C=0.01939e(-0.0434t), C=0.01425e(-0.8111t), and C=1.171e(-0.198t), respectively; the half-lives were about 16.0 d, 0.85 d and 3.50 d, respectively. The degradation rate of chlorantraniliprole in water was the fastest, followed by rice straw. The final residues of chlorantraniliprole on brown rice were lower than maximum residue limit (MRL) of 0.02 mg kg(-1) after 14 d Pre-Harvest Interval (PHI). Therefore, a dosage of 150 mL a.i.hm(-2) was recommended, which could be considered as safe to human beings and animals.     

Evidence for enhanced dissipation of chlorpyrifos in an agricultural soil inoculated with Serratia rubidaea strain ABS 10

The insecticide ¹⁴C-chlorpyrifos was found mineralized in a Tunisian soil with repeated exposure to it. From this soil, a bacterial strain was isolated that was able to grow in a minimal salt medium (MSM) supplemented with 25 mg L^?1 of chlorpyrifos. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In a liquid culture, the S. rubidaea strain ABS 10 was able to dissipate chlorpyrifos almost entirely within 48 h of incubation. Although the S. rubidaea strain ABS 10 was able to grow in an MSM supplemented with chlorpyrifos and dissipate it in a liquid culture, it was not able to mineralize ¹⁴C-chlorpyrifos. Therefore, it can be concluded that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. It can also be ascribed to other reasons such as the formation of biogenic non-extractable residues. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in controls with DT₅₀ of 1.38 and 1.05 days, respectively.

     

Pesticide distribution in an agricultural environment in Argentina

An assessment of the off-site migration of pesticides from agricultural activity into the environment in the Neuquen River Valley was performed. The aim of this study was to evaluate the distribution of pesticides in several compartments of a small agricultural sub-catchment. Soil, surface water, shallow groundwater and drift deposition were analyzed for pesticide residues. Results showed the presence of some pesticide residues in soil, surface water and shallow groundwater compartments. The highest detection frequencies in water (surface and subsurface) were found for azinphos-methyl and chlorpyrifos (>70%). In terms of concentration, the highest levels were observed in shallow groundwater for azinphos methyl (22.5 μg/L) and carbaryl (45.7 μg/L). In the soil, even before the application period had started, accumulation of residues was present. These residues increased during the period studied. Spray drift during pesticide application was found to be a significant pathway for the migration of pesticide residues in surface water, while leaching and preferential flows were the main transport routes contributing to subsurface contamination.     

稻秆对铜绿微囊藻抑制作用的研究

研究了稻秆浸出液对铜绿微囊藻生长的抑制作用.研究表明,稻秆浸出液中含有的化学物质抑制了铜绿微囊藻的生长繁殖.稻秆浸泡时间的延长,有利于提高浸出液的抑藻效果,但浸泡时间过长则无益于抑藻效果提高,浸泡时间为15 d时,抑制率能高达75.99%.稻秆浸出液投加量达7.5%以上具有显著的抑藻效果.不同部位的水稻秸秆浸出液对铜绿...     

Residues and dynamics of pymetrozine in rice field ecosystem

The fate of pymetrozine was studied in rice field ecosystem, and a simple and reliable analytical method for determination of pymetrozine in soil, rice straw, paddy water and brown rice was developed. Pymetrozine residues were extracted from samples, cleaned up by solid phase extraction (SPE) and then determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). The average recovery was 81.2-88.1% from soil, 83.4-88.6% from rice straw, 87.3-94.1% from paddy water and 82.9-85.3% from brown rice. The relative standard deviation (RSD) was less than 15%. The limits of detection (LODs) of pymetrozine calculated as a sample concentration were 0.0003 mg kg⁻¹ (mg L⁻¹) for soil and paddy water, 0.001 mg kg⁻¹ for brown rice and rice straw. The results of kinetics study of pymetrozine residue showed that pymetrozine degradation in water, soil, and rice straw coincided with C = 0.194e^−0.986t, C = 0.044e^−0.099t, and C = 0.988e^−0.780t, respectively; the half-lives were about 0.70 d, 7.0 d and 0.89 d, respectively. The degradation rate of pymetrozine in water was the fastest, followed by rice straw. The highest final pymetrozine residues in brown rice were 0.01 mg kg⁻¹, which was lower than the EU’s upper limit of 0.02 mg kg⁻¹ in rice. Therefore, a dosage of 300-600 g a.i.hm⁻² was recommended, which could be considered as safe to human beings and animals.     

Chlorinated Pesticides (2,4-D and DDT) Biodegradation at High Concentrations Using Immobilized Pseudomonas Fluorescens

Abstract

Degradation of two chlorinated pesticides (2,4-D and DDT) using a 54-mL glass column packed with tezontle (a low-cost basaltic scoria) was tested. Bacteria were cultured in YPG (yeast, peptone, and glucose) liquid medium at 32°C. The rich medium was pumped during 24 h through the column to inoculate it. Later, the wasted medium was discharged and the pesticide added. Optical densities, TOC, and pesticide concentration were determined. Pesticide removals for 2,4-D (with initial concentration between 100 and 500 mg/L) were about 99%. DDT removal (at initial concentration of up to 150 mg/L) was as high as 55–99%. TOC removals for 2,4-D was in the 36-87% interval, whereas for DDT they were as high as 36–78%.     

Pesticide distribution in an agricultural environment in Argentina

An assessment of the off-site migration of pesticides from agricultural activity into the environment in the Neuquen River Valley was performed. The aim of this study was to evaluate the distribution of pesticides in several compartments of a small agricultural sub-catchment. Soil, surface water, shallow groundwater and drift deposition were analyzed for pesticide residues. Results showed the presence of some pesticide residues in soil, surface water and shallow groundwater compartments. The highest detection frequencies in water (surface and subsurface) were found for azinphos-methyl and chlorpyrifos (>70%). In terms of concentration, the highest levels were observed in shallow groundwater for azinphos methyl (22.5 μg/L) and carbaryl (45.7 μg/L). In the soil, even before the application period had started, accumulation of residues was present. These residues increased during the period studied. Spray drift during pesticide application was found to be a significant pathway for the migration of pesticide residues in surface water, while leaching and preferential flows were the main transport routes contributing to subsurface contamination.     

Evaluation of bioaugmentation and biostimulation on arsenic remediation in soil through biovolatilization

Arsenic (As) removal through microbially driven biovolatilization can be explored as a potential method for As bioremediation. However, its effectiveness needs to be improved. Biostimulation with organic matter amendment and bioaugmentation with the inoculation of genetic engineered bacteria could be potential strategies for As removal and site remediation. Here, the experiments were conducted to evaluate the impacts of rice straw and biochar amendment, inoculation of genetic engineered Pseudomonas putida KT2440 (GE P. putida) with high As volatilization activity, on microbial mediated As volatilization and removal from three different arseniferous soils. In general, the addition of rice straw (5%) significantly enhanced As methylation and volatilization in comparison with corresponding non-amended soils. Biochar amendments and inoculation of the GE P. putida increased As methylation and volatilization, respectively, but less than that of rice straw addition. The effectiveness of As volatilizations are quite different in the various paddy soils. The combined amendments of rice straw and GE P. putida exhibited the highest As removal efficiency (483.2 μg/kg/year) in Dayu soil, with 1.2% volatilization of the total As annually. The highest water-soluble As concentration (0.73 mg/kg) in this soil could be responsible for highest As volatilization besides the rice straw and bacteria in this soil.     

Effect of clarification process on the removal of pesticide residues in red wine and comparison with white wine

The aim of this study was to determine the potential of seven clarifying agents to remove pesticides in red wine. The presence of pesticides in wine consists a great problem for winemakers and therefore, results on pesticide removal by clarification are very useful for taking a decision on the appropriate adsorbent. The selection of an efficient adsorbent can be based on data correlating pesticide removal in red wine to pesticides' properties, given the great number and variety of pesticides used. So, this experimental work is focused on the collection of results with regard to pesticide removal by clarification using a great number of pesticides and fining agents. A Greek red wine, fortified with single solutions and mixtures of 23 or 9 pesticides was studied. The seven fining agents, used at two concentrations, were activated carbon, bentonite, polyvinylpolypyrrolidone (PVPP), gelatin, egg albumin, isinglass-fish glue, and casein. Pesticides were selected with a wide range of properties (octanol–water partition coefficient (log K_ow) 2.7–6.3 and water solubility 0.0002–142) and belong to 11 chemical groups. Solid phase extraction (SPE) followed by gas chromatography (GC) with electron capture detector (ECD) were performed to analyze pesticide residues of the clarified fortified wine. The correlation of the clarifying agents' effectiveness to pesticide's chemical structure and properties (log K_ow, water solubility) was investigated. The antagonistic and/or synergistic effects, occurring among the pesticides in the mixtures, were calculated by indices. Pesticide removal effectiveness results of the red wine were compared to those obtained from a white wine under the same experimental conditions and discussed. The order of decreasing adsorbent effectiveness (mixture of 23 pesticides) was: activated carbon 40% > gelatin 23% > egg albumin 21% > PVPP 18% > casein 12% > bentonite 7%. Isinglass showed 12% removal at the highest permitted concentration. In the case of 9 pesticides mixture, the effectiveness was quite higher but the order remained the same compared to 23 pesticides mixture. The removal of each pesticide from its single solution was generally the highest (particularly for hydrophobic pesticides). Adsorption on fining agents is increased by increasing hydrophobicity and decreasing hydrophilicity of organic pesticide molecules.     

Parameters affecting azoxystrobin and imidacloprid degradation in biobed substrates in the North Indian tropical environment

Abstract

This study reports degradation of azoxystrobin (AZOXY) and imidacloprid (IMIDA) in the rice straw (RS)/corn cob (CC) and peat (P)/compost (C)-based biomixtures. The effect of biomixture preconditioning (10?days incubation prior to pesticide application), pesticide concentration and moisture content was evaluated. Results suggested that conditioning of biomixture greatly affected IMIDA degradation where half-life (t_1/2) was reduced by 5–9 times. This was attributed to higher microbial biomass carbon content and dehydrogenase activity in the conditioned biomixtures. Pesticide application in the conditioned biomixture did not show any negative impact on soil microbial parameters. Both pesticides degraded at faster rate in the rice straw-based biomixtures than in the corn cob-based biomixtures. Degradation slowed down with increase in initial concentration of pesticides in biomixture and 1.6–3.0 (AZOXY) and 2.4–3.6 (IMIDA) times increase in t_1/2 values was observed. The moisture content of biomixture showed positive effect on degradation which increased when moisture content was increased from 60 to 80% water holding capacity. The effect was significant for IMIDA degradation in the corn cob-based biomixtures and AZOXY degradation in the peat biomixtures. The rice straw-based biomixtures were better in degrading AZOXY and IMIDA and can be used in biopurification systems.     

Comparative acute toxicities of selected pesticides to Anguilla anguilla

Abstract

The acute toxicities (24, 48, 72 and 96 hr) of eight pesticides to Anguilla anguilla were determined. The organochlorine pesticide, endosulfan was the most toxic, with LC50 values in the range of 0.042 to 0.041 mg/L Endosulfan was followed in order of decreasing toxicity by diazinon, fenitrothion, chlorpyrifos, lmdane, methidathion, trichlorfon and methylparathion. When fishes were exposed to the pesticides tested they exhibited signs of restlessness, erratic swimming, convulsions and difficulty in respiration. This response was more persistent in fishes exposed to organophosphorus pesticides.     

Use of molecular and In Silico bioinformatic tools to investigate pesticide binding to insect (Lepidoptera) phenoloxidases (PO): Insights to toxicological aspects

In the present work, the promising bioinformatic tools, based on structure–affinity analysis, allowed to screen several pesticides supposed to bind to the insect immune Phenoloxidases (PO). First, the binding of aminoparathion, a reference compound, to the PO was structurally (3D) validated in accordance with previous reports. Second, using the same docking conditions, a range of pesticides was checked for their binding ability to the crystal 3D structure (PDB 3HSS) of the insect Manduca sexta (Lepidoptera) PO. The obtained data showed that many of the tested pesticides were able to bind, in silico, to M. sexta PO. The combination of in vitro (chemical and biochemical) and in silico (automated docking) approaches was found advantageous to elucidate the behavior of phenolic pesticides as substrate-analogues when binding to the active site of insect POs. Our findings emphasize new ecotoxicological aspects of pesticide residues in the agro-chemical and environmental circles.     

Removal of Aldrin,Dieldrin, Heptachlor,and Heptachlor Epoxide Using Activated Carbon and/or Pseudomonas fluorescens Free Cell Cultures

Degradation of aldrin (1,2,3,4,10,10-Hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5-8-dimethanonaphthalene), heptachlor (1H-1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano indene), dieldrin (1aα,2β,2aα,3β,6β,6aα,7β,7aα)-3,4,5,6,9,9-Hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-d-methanonaphtha[2,3-b]oxirene, and heptachlor epoxide (1aα, 1bβ,2α,5α,5αβ,6β,6aα-2,3,4,5,6,7,7-Heptachloro-1a,1b,5,5a,6,6a-hexahydro-2,5-methano-2H-inden[1,2-b]-oxirene) was tested using free cultures of Pseudomonas fluorescens under controlled conditions. Pesticide concentrations were monitored by gas chromatography during 120 h. Percentages of degradation and biodegradation rates (BDR) were calculated. Data showed a trend suggesting a relation between chemical structure and degradability. Degradation kinetics for each pesticide tested showed that the highest degradation rates were found in the first 24 h. Kinetics data were adjusted to an empirical equation in order to predict their behavior, and the correlation coefficients obtained were satisfactory. Gas chromatography/mass spectrometry (GC/MS) analysis of the final extracts allowed the identification of chlordene and monodechlorodieldrin, which have been reported as final metabolite produced in the biodegradation of this kind of compounds. Regarding adsorption of pesticides on activated vegetal carbon, we concluded that removal efficiencies between 95.45 and 97.18% can be reached, depending on the pesticide and the carbon dose applied. The values for K from the Freundlich equation were quite similar for the four pesticides (between 1.0001 and 1.04), whereas the n values were quite different for each pesticide in the following order of affinity: dieldrin > aldrin > heptachlor epoxide > heptachlor. Equilibrium times, very important for scaling up the process, were between 43 min and 1 h, for the heptachlor epoxide and the heptachlor, respectively.     

Metabolism of the14C-labeled herbicide clodinafop-propargyl in plant cell cultures of wheat and tobacco

The metabolism of ¹⁴C-clodinafop-propargyl (CfP) was examined in cell cultures of wheat (Triticum aestivum L. cv. ‘Heines Koga II’) and tobacco (Nicotiana tabacum L.). Besides the non-transgenic tobacco culture, cultures transformed separately with cDNA of human cytochrome P450-monooxygenases (P450s) CYP1A1, CYP1A2, CYP3A4, CYP2B6 and CYP2C19 were examined. Experiments with wheat were executed in the presence and absence of safener cloquintocet-mexyl (CqM). After 48 h of incubation, only about 10% of applied ¹⁴C was found in media (both tobacco and wheat). Non-extractable residues of ¹⁴C-CfP in wheat cells were 16.54% (without CqM) and 30.87% (with CqM). In all tobacco cultures, 82.41–92.46% of applied radioactivity was recovered in cell extracts. In contrast to wheat, non-extractable residues amounted only to 1.50–2.82%. As determined by radio-thin layer chromatography (TLC) and -high-performance liquid chromatography (HPLC), the parent CfP was not found in the cell extracts of wheat; in tobacco cell extracts, only traces of CfP were detected. After a hydrolysis of assumed carbohydrate conjugates of CfP derived polar ¹⁴C-labeled compounds, TLC and HPLC analysis showed that in wheat, a more complex pattern of metabolites of CfP were observed as compared to all tobacco cultures. In hydrolysates resulting from wheat, the identity of three primary products was confirmed by means of GC-EI-MS: free acid clodinafop (Cf), hydroxy-Cf hydroxylated at the pyridinyl moiety, and 4-(5-chloro-3-fluoropyridin-2-yloxy)phenol. In hydrolysates derived from all tobacco cultures, main metabolite was Cf besides only traces of further unidentified products. Differences among the different tobacco cultures (non-transgenic, transgenic) did not emerge. According to kinetics of disappearance of primary metabolite Cf as well as formation of polar soluble products and non-extractable residues, metabolization of CfP proceeded at a noticeably higher rate in wheat cells treated with safener CqM than in cells without CqM treatment. Thus, these results indicated a stimulation of CfP's metabolism by CqM, although metabolic profiles observed in CqM treated and non-treated cells (after hydrolysis) were qualitatively similar. The findings obtained from all tobacco cultures suggested that with the exception of ester cleavage to Cf, CfP cannot be metabolized by tobacco itself or by the human P450s examined.     

非活体生物质对水中活性艳红X-3B的吸附研究

研究了4种非活体生物质(米酒糟、花生壳、柚子皮、稻草秸秆)对模拟废水中活性艳红X-3B的吸附条件及吸附机理。结果表明,活性艳红X-3B初始浓度为100 mg/L、pH为1.0~2.0、吸附剂浓度为10 mg/L时,4种吸附剂对活性艳红X-3B的吸附率可达到80%。吸附在60 min左右达平衡后最大吸附量的顺序为:米酒糟(58.8 mg/g)花生壳(28.0mg/g)柚子皮(23.6 mg/g)稻草秸秆(19.5 mg/g)。在达最大吸附率时,米酒糟的用量可减少一半、pH范围可宽为1.0~6.0,且吸附量是另三者的2倍以上。综合比较,米酒糟具有较强的吸附废水中活性艳红X-3B的能力,可作为废水中活性染料的吸附剂使用。而花生壳、柚子皮和稻草秸秆的吸附能力相对较弱,不是理想的吸附材料。数学模型模拟表明,米酒糟和柚子皮的吸附过程更符合Freundlich方程,而花生壳和稻草秸秆更符合Langmuir方程;动力学研究表明4种吸附剂的吸附拟合更符合拟二级动力学方程。