Solid-state fermentation: tool for bioremediation of adsorbed textile dyestuff on distillery industry waste-yeast biomass using isolated Bacillus cereus strain EBT1

Bioremediation of textile dyestuffs under solid-state fermentation (SSF) using industrial wastes as substrate pose an economically feasible, promising, and eco-friendly alternative. The purpose of this study was to adsorb Red M5B dye, a sample of dyes mixture and a real textile effluent on distillery industry waste-yeast biomass (DIW-YB) and its further bioremediation using Bacillus cereus EBT1 under SSF. Textile dyestuffs were allowed to adsorb on DIW-YB. DIW-YB adsorbed dyestuffs were decolorized under SSF by using B. cereus. Enzyme analysis was carried out to ensure decolorization of Red M5B. Metabolites after dye degradation were analyzed using UV–Vis spectroscopy, FTIR, HPLC, and GC-MS. DIW-YB showed adsorption of Red M5B, dyes mixture and a textile wastewater sample up to 87, 70, and 81 %, respectively. DIW-YB adsorbed Red M5B was decolorized up to 98 % by B. cereus in 36 h. Whereas B. cereus could effectively reduce American Dye Manufacture Institute value from DIW-YB adsorbed mixture of textile dyes and textile wastewater up to 70 and 100 %, respectively. Induction of extracellular enzymes such as laccase and azoreductase suggests their involvement in dye degradation. Repeated utilization of DIW-YB showed consistent adsorption and ADMI removal from textile wastewater up to seven cycles. HPLC and FTIR analysis confirms the biodegradation of Red M5B. GC-MS analysis revealed the formation of new metabolites. B. cereus has potential to bioremediate adsorbed textile dyestuffs on DIW-YB. B. cereus along with DIW-YB showed enhanced decolorization performance in tray bioreactor which suggests its potential for large-scale treatment procedures.     

Biosorption of synthetic dyes (Direct Red 89 and Reactive Green 12) as an ecological refining step in textile effluent treatment

With the use of cost-effective natural materials, biosorption is considered as an ecological tool that is applied worldwide for the remediation of pollution. In this study, we proposed Lemna gibba biomass (LGB), a lignocellulosic sorbent material, for the removal of two textile dyes, Direct Red 89 (DR-89) and Reactive Green 12 (RG-12). These azo dyes commonly used in dying operations of natural and synthetic fibres are the most important pollutants produced in textile industry effluents. For this purpose, batch biosorption experiments were carried out to assess the efficacy of LGB on dye treatment by evaluating the effect of contact time, biomass dosage, and initial dye concentration. The results indicated that the bioremoval efficiency of 5 mg?L^?1 DR-89 and RG-12 reached approximately 100 % after 20 min of the exposure time; however, the maximum biosorption of 50 mg?L^?1 DR-89 and 15 mg?L^?1 RG-12 was determined to be about 60 and 47 %, respectively. Fourier transform infrared spectroscopy used to explain the sorption mechanism showed that the functional groups of carboxylic acid and hydroxyl played a major role in the retention of these pollutants on the biomass surface. The modelling results using Freundlich, Langmuir, Temkin, Elovich, and Dubini Radushkevich (D-R) isotherms demonstrated that the DR-89 biosorption process was better described with the Langmuir theory (R ²?=?0.992) while the RG-12 biosorption process fitted well by the D-R isotherm equation (R ²?=?0.988). The maximum biosorption capacity was found to be 20.0 and 115.5 mg?g^?1 for DR-89 and RG-12, respectively, showing a higher ability of duckweed biomass for the bioremoval of the green dye. The thermodynamic study showed that the dye biosorption was a spontaneous and endothermic process. The efficacy of using duckweed biomass for the bioremoval of the two dyes was limited to concentrations ≤50 mg?L^?1, indicating that L. gibba biomass may be suitable in the refining step of textile effluent treatment.     

Synthesis of Fe-doped Bi<Subscript>2</Subscript>O<Subscript>3</Subscript> nanocatalyst and its sonophotocatalytic activity on synthetic dye and real textile wastewater

The catalysts such as Fe, Bi₂O₃, and Fe-doped Bi₂O₃ were synthesized for the sonophotocatalytic treatment of synthetic dye and real textile wastewater. The resultant catalysts were characterized for its size and uniform shape using x-ray diffractogram (XRD) and scanning electron microscopy (SEM) which signified the nanorod shape formed Bi₂O₃. The higher ultraviolet light absorbance capacity of the catalysts was also evident using diffuse reflectance spectroscopy (DRS). Initially, the effect of conventional parameters such as initial pH, gas bubbling (argon, oxygen, air and nitrogen) and oxidant addition (H₂O₂ and peroxymonosulfate) in the presence of sonolysis (22 and 37 kHz frequency) and photolysis (UV-C light) on 10 ppm Basic Brown 1 dye was studied. The results showed that highest decolorization of 62 % was attained for 3 g/L peroxymonosulfate under 37 kHz frequency sonolysis treatment. Secondly, with the catalyst study, highest of 46 % dye color removal was obtained with 4 g/L Fe under 37 kHz frequency sonolysis treatment. The sonophotocatalytic treatment of dye with Fe-doped Bi₂O₃ catalyst in combination with peroxymonosulfate showed highest color removal of 99 %. Finally, the sonophotocatalytic treatment of real textile wastewater in the presence of 3 g/L Fe-doped Bi₂O₃ and 6 g/L peroxymonosulfate reduced the total organic carbon (TOC) and chemical oxygen demand (COD) level to 77 and 91 %, respectively, in 180 min. The reported treatment process was found to treat the synthetic dye and real textile wastewater effectively.     

Treatment of Basic Red 29 dye solution using iron-aluminum electrode pairs by electrocoagulation and electro-Fenton methods

The aim of this study is the treatment of Basic Red 29 (BR29) dye solution using hybrid iron-aluminum electrodes by electrocoagulation and electro-Fenton methods. The effect of current density, initial pH, supporting electrolyte, H₂O₂, and initial dye concentration on dye removal efficiency was investigated, and the best experimental conditions were obtained. Time-coarse variation of UV-Vis spectra and toxicity and chemical oxygen demand (COD) removal were also examined at the best experimental conditions. Both systems were found very successful for the removal of BR29 dye. The removal efficiency of >95 % for BR29 dye solution was reached easily in a short time. At the best experimental conditions, for the initial BR29 concentration of 100 mg/L, >95 % BR29 dye and 71.43 % COD removal were obtained after 20 and 40 min of electrolysis, respectively. Additionally, toxicity results for electro-Fenton treatment of 100 mg/L BR29 were also very promising. According to the results obtained, although electro-Fenton is more effective, both systems can be used successfully to treat textile wastewater including dyes.     

Comparative performance evaluation of Aspergillus lentulus for dye removal through bioaccumulation and biosorption

Dyes used in various industries are discharged into the environment and pose major environmental concern. In the present study, fungal isolate Aspergillus lentulus was utilized for the treatment of various dyes, dye mixtures and dye containing effluent in dual modes, bioaccumulation (employing growing biomass) and biosorption (employing pre-cultivated biomass). The effect of dye toxicity on the growth of the fungal isolate was studied through phase contrast and scanning electron microscopy. Dye biosorption was studied using first and second-order kinetic models. Effects of factors influencing adsorption and isotherm studies were also conducted. During bioaccumulation, good removal was obtained for anionic dyes (100 mg/l), viz. Acid Navy Blue, Fast Red A and Orange-HF dye (99.4 %, 98.8 % and 98.7 %, respectively) in 48 h. Cationic dyes (10 mg/l), viz. Rhodamine B and Methylene Blue, had low removal efficiency (80.3 % [48 h] and 92.7 % [144 h], respectively) as compared to anionic dyes. In addition to this, fungal isolate showed toxicity response towards Methylene Blue by producing larger aggregates of fungal pellets. To overcome the limitations of bioaccumulation, dye removal in biosorption mode was studied. In this mode, significant removal was observed for anionic (96.7–94.3 %) and cationic (35.4–90.9 %) dyes in 24 h. The removal of three anionic dyes and Rhodamine B followed first-order kinetic model whereas removal of Methylene Blue followed second-order kinetic model. Overall, fungal isolate could remove more than 90 % dye from different dye mixtures in bioaccumulation mode and more than 70 % dye in biosorption mode. Moreover, significant color removal from handmade paper unit effluent in bioaccumulation mode (86.4 %) as well as in biosorption mode (77.1 %) was obtained within 24 h. This study validates the potential of fungal isolate, A. lentulus, to be used as the primary organism for treating dye containing wastewater.     

Effects of high ammonium level on biomass accumulation of common duckweed Lemna minor L.

Growing common duckweed Lemna minor L. in diluted livestock wastewater is an alternative option for pollutants removal and consequently the accumulated duckweed biomass can be used for bioenergy production. However, the biomass accumulation can be inhibited by high level of ammonium (NH₄ ⁺) in non-diluted livestock wastewater and the mechanism of ammonium inhibition is not fully understood. In this study, the effect of high concentration of NH₄ ⁺ on L. minor biomass accumulation was investigated using NH₄ ⁺ as sole source of nitrogen (N). NH₄ ⁺-induced toxicity symptoms were observed when L. minor was exposed to high concentrations of ammonium nitrogen (NH₄ ⁺-N) after a 7-day cultivation. L. minor exposed to the NH₄ ⁺-N concentration of 840 mg l^?1 exhibited reduced relative growth rate, contents of carbon (C) and photosynthetic pigments, and C/N ratio. Ammonium irons were inhibitory to the synthesis of photosynthetic pigments and caused C/N imbalance in L. minor. These symptoms could further cause premature senescence of the fronds, and restrain their reproduction, growth and biomass accumulation. L. minor could grow at NH₄ ⁺-N concentrations of 7–84 mg l^?1 and the optimal NH₄ ⁺-N concentration was 28 mg l^?1.     

Coal fly ash as adsorptive material for treatment of a real textile effluent: operating parameters and treatment efficiency

The experimental results performed after the application of one single-stage treatment by sorption onto coal fly ash are evaluated in order to decolorize a real textile effluent of a private company specializing in manufacturing of cotton fabrics (i.e., sorption performance applied for a real textile effluent collected after the fabric dyeing, rinsing, and final finishing steps). The experiments are focused on studying the effect of initial textile effluent pH, adsorbent dose, temperature and adsorption time, considered as operating parameters of sorption process for high pollutant removals (e.g., organic pollutants as dyes, phenols, polymeric, and degradation compounds), and decoloration. The results indicate high values of decoloration degree (55.42–83.00 %) and COD removal (44.44–61.11 %) when it is worked at pH ≤2 with coal ash dose of 12–40 g/L, temperature higher than 20–25 °C, and continuous static operating regime (with an initial agitation step of 3–5 min). The treated textile effluent fulfills the quality demand, and is recyclable, inside reused or discharged after a stage of neutralization (standard pH of 6.5–8.5 for all textile effluent discharges). Also, the final effluent is able to follow the common path to the central biological treatment plant (i.e., a centralized treatment plant for all companies acting in the industrial site area with mechanical–biological steps for wastewater treatment) or may be directly discharged in the nearly watercourse.     

Biosorption of arsenic from aqueous solution using dye waste

The purpose of this study is to examine on removal of arsenic from water by biosorption through potential application of herbal dye wastes. Four different flower dye residues (after extraction of natural dye) viz. Hibiscus rosasinensis, Rosa rosa, Tagetes erecta, and Canna indica were utilized successfully for the removal of arsenic from aqueous solution. Batch studies were carried out for various parameters viz. pH, sorbent dose, contact time, initial metal ion concentration, and temperature. Data were utilized for isothermal, kinetic, and thermodynamic studies. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDAX), and Fourier transform infrared (FTIR) analyses of biomass were performed. The results showed that 1 g/100 ml for 5.0–5.5 h contact time at pH 6.0–7.5 with agitation rate 150 rpm provided 98, 96, 92, and 85 % maximum absorption of arsenic by R. rosa, H. rosasinensis, T. erecta, and C. indica, respectively, at initial concentration of 500 ppb. Data followed Langmuir isotherm showing sorption to be monolayer on heterogeneous surface of biosorbent. Negative values of ΔG° indicated spontaneous nature, whereas ΔH° indicates exothermic nature of system followed by pseudo-first-order adsorption kinetics. FTIR results showed apparent changes in functional group regions after metal chelation. SEM and EDAX analyses showed the changes in surface morphology of all test biosorbents. Herbal dye wastes, used as biosorbent, exhibited significant (85–98 %) removal of arsenic from aqueous solution. Hence, these biosorbents are cost-effective, easily available, eco-friendly, and comparatively more effective than other biosorbents already in use. These may be used to remove arsenic and other toxic metals from water.     

清浊分流条件下的混凝-臭氧处理棉针织印染清废水

根据污染源头控制和废水回用的要求,对典型棉针织染整厂的不同生产过程废水排水水质特征进行了统计分析,提出了较实用的废水源头清浊分流方案。在此基础上重点研究了混凝-臭氧组合工艺对清废水处理效果,确定了最优的工艺条件。结果表明,清废水主要为洗水,占废水总量的25%～30%;混凝-臭氧组合工艺的最优工艺条件为：pH为6～9,PAC投加量为48 mg/L,PAM投加量为1.0 mg/L,臭氧接触时间为12 min（臭氧浓度为14.5 mg/L）,这时,清废水COD、色度去除率分别为71%和98%,实践证明,出水水质完全能够满足染整生产。     

Comparison of experimental ponds for the treatment of dye wastewater under controlled and semi-natural conditions

This study compares the performance of simulated shallow ponds vegetated with Lemna minor L. under controlled and semi-natural conditions for the treatment of simulated wastewater containing textile dyes. The objectives were to assess the water quality outflow parameters, the potential of L. minor concerning the removal of chemical oxygen demand (COD) and four azo dyes (Acid blue 113, reactive blue 198, Direct Orange 46 and Basic Red 46) and the plants’ growth rate. Findings show that all mean outflow values of COD, total dissolved solids (TDS) and electrical conductivity (EC) were significantly (p < 0.05) lower within the outdoor compared to the indoor experiment except the dissolved oxygen (DO). The COD removal was low for both experiments. The outflow TDS values were acceptable for all ponds. The pond systems were able to reduce only BR46 significantly (p < 0.05) for the tested boundary conditions. Removals under laboratory conditions were better than those for semi-natural environments, indicating the suitability of operating the pond system as a polishing step in warmer regions. The mean outflow values of zinc and copper were below the thresholds set for drinking and irrigation waters and acceptable for L. minor. The dyes inhibited the growth of the L. minor.     

Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: optimization by response surface methodological approach

Reactive dyes account for one of the major sources of dye wastes in textile effluent. In this study, decolorization of the monoazo dye, Acid Orange 7 (AO7) by the Enterococcus faecalis strain ZL that isolated from a palm oil mill effluent treatment plant has been investigated. Decolorization efficiency of azo dye is greatly affected by the types of nutrients and the size of inoculum used. In this work, one-factor-at-a-time (method and response surface methodology (RSM) was applied to optimize these operational factors and also to study the combined interaction between them. Analysis of AO7 decolorization was done using Fourier transform infrared (FTIR) spectroscopy, desorption study, UV–Vis spectral analysis, field emission scanning electron microscopy (FESEM), and high performance liquid chromatography (HPLC). The optimum condition via RSM for the color removal of AO7 was found to be as follows: yeast extract, 0.1 %?w/v, glycerol concentration of 0.1 %?v/v, and inoculum density of 2.5 %?v/v at initial dye concentration of 100 mg/L at 37 °C. Decolorization efficiency of 98 % was achieved in only 5 h. The kinetic of AO7 decolorization was found to be first order with respect to dye concentration with a k value of 0.87/h. FTIR, desorption study, UV–Vis spectral analysis, FESEM, and HPLC findings indicated that the decolorization of AO7 was mainly due to the biosorption as well as biodegradation of the bacterial cells. In addition, HPLC analyses also showed the formation of sulfanilic acid as a possible degradation product of AO7 under facultative anaerobic condition. This study explored the ability of E. faecalis strain ZL in decolorizing AO7 by biosorption as well as biodegradation process.     

Biochemical response to exposure to six textile dyes in early developmental stages of Xenopus laevis

The present study was undertaken to determine the toxic effect of a lethal concentration of six different commercially used textile dyes on the 46th stage of Xenopus laevis tadpoles. The tadpoles were exposed to Astrazon Red FBL, Astrazon Blue FGRL, Remazol Red RR, Remazol Turquoise Blue G-A, Cibacron Red FN-3G, and Cibacron Blue FN-R for 168 h in static test conditions, and thus, 168-h median lethal concentrations (LC₅₀s) of each dye were determined to be 0.35, 0.13, 112, 7, 359, and 15.8 mg/L, respectively. Also, to evaluate the sublethal effects of each dye, tadpoles were exposed to different concentrations of dyes (with respect to 168-h LC₅₀s) for 24 h. The alteration of selected enzyme activities was tested. For this aim, glutathione S-transferase (GST), carboxylesterase, and lactate dehydrogenase (LDH) were assayed. After dye exposure, the GST induction or inhibition and LDH induction indicated some possible mechanisms of oxidative stress and deterioration in aerobic respiration processes induced by the tested dyes. Findings of the study suggest that selected biomarker enzymes are useful in understanding the toxic mechanisms of these dyes in X. laevis tadpoles as early warning indicators. Therefore, these selected biomarkers may evaluate the effect of environmental factors, such as textile dye effluents and other industrial pollutants, on amphibians in biomonitoring studies.     

Equilibrium, kinetic and thermodynamic studies on the biosorption of reactive acid dye on Enteromorpha flexuosa and Gracilaria corticata

Purpose

Biosorption is an emerging, eco-friendly and economical method for treating the wastewater effluents. Compared to many other biological materials, algae biomass proved to be the better biosorbent due to the presence of cell wall polymers in them.

Methods

Algal biomasses namely Enteromorpha flexuosa and Gracilaria corticata were dried, crushed and used as biosorbents. Ponceau S, a diazo dye was used as a model adsorbate for the biosorption studies. The biosorbents were characterized by Scanning Electron Microscopy, FT-IR and zero point charge. Batch studies were performed by varying pH, biosorbent dosage and initial dye concentrations. Adsorption isotherms, kinetic and thermodynamic analyses were carried out. The effect of electrolytes was also studied. Batch desorption studies were also carried out using various reagents.

Results

Isotherm data were tested with Langmuir and Freundlich isotherm models and the results suggested that the Freundlich isotherm fitted the data well. Kinetic studies were performed with varying initial dye concentrations and the data were incorporated with pseudo first-order and pseudo second-order kinetic equations and was found that the studied biosorption processes followed pseudo second-order kinetic equation. Thermodynamic parameters were evaluated at three different temperatures 293?K, 300?K and 313?K. About 95% of the dye could be desorbed from both the biosorbents.

Conclusion

Both the algal biomasses had heterogeneous surfaces and followed pseudo second-order chemical kinetics. Thermodynamic parameters proved that the biosorption by both the biomasses were spontaneous, feasible and endothermic processes. Desorption studies proved the worth of the algal biomasses as biosorbents in industrial level.     

Biodegradation of methyl red by Bacillus sp. strain UN2: decolorization capacity,metabolites characterization,and enzyme analysis

Azo dyes are recalcitrant and refractory pollutants that constitute a significant menace to the environment. The present study is focused on exploring the capability of Bacillus sp. strain UN2 for application in methyl red (MR) degradation. Effects of physicochemical parameters (pH of medium, temperature, initial concentration of dye, and composition of the medium) were studied in detail. The suitable pH and temperature range for MR degradation by strain UN2 were respectively 7.0–9.0 and 30–40 °C, and the optimal pH value and temperature were respectively 8.0 and 35 °C. Mg²⁺ and Mn²⁺ (1 mM) were found to significantly accelerate the MR removal rate, while the enhancement by either Fe³⁺ or Fe²⁺ was slight. Under the optimal degradation conditions, strain UN2 exhibited greater than 98 % degradation of the toxic azo dye MR (100 ppm) within 30 min. Analysis of samples from decolorized culture flasks confirmed biodegradation of MR into two prime metabolites: N,N′dimethyl-p-phenyle-nediamine and 2-aminobenzoic acid. A study of the enzymes responsible for the biodegradation of MR, in the control and cells obtained during (10 min) and after (30 min) degradation, showed a significant increase in the activities of azoreductase, laccase, and NADH-DCIP reductase. Furthermore, a phytotoxicity analysis demonstrated that the germination inhibition was almost eliminated for both the plants Triticum aestivum and Sorghum bicolor by MR metabolites at 100 mg/L concentration, yet the germination inhibition of parent dye was significant. Consequently, the high efficiency of MR degradation enables this strain to be a potential candidate for bioremediation of wastewater containing MR.     

Treatment of Arctic wastewater by chemical coagulation,UV and peracetic acid disinfection

Conventional wastewater treatment is challenging in the Arctic region due to the cold climate and scattered population. Thus, no wastewater treatment plant exists in Greenland, and raw wastewater is discharged directly to nearby waterbodies without treatment. We investigated the efficiency of physicochemical wastewater treatment, in Kangerlussuaq, Greenland. Raw wastewater from Kangerlussuaq was treated by chemical coagulation and UV disinfection. By applying 7.5 mg Al/L polyaluminium chloride (PAX XL100), 73% of turbidity and 28% phosphate was removed from raw wastewater. E. coli and Enterococcus were removed by 4 and 2.5 log, respectively, when UV irradiation of 0.70 kWh/m³ was applied to coagulated wastewater. Furthermore, coagulated raw wastewater in Denmark, which has a chemical quality similar to Greenlandic wastewater, was disinfected by peracetic acid or UV irradiation. Removal of heterotrophic bacteria by applying 6 and 12 mg/L peracetic acid was 2.8 and 3.1 log, respectively. Similarly, removal of heterotrophic bacteria by applying 0.21 and 2.10 kWh/m³ for UV irradiation was 2.1 and greater than 4 log, respectively. Physicochemical treatment of raw wastewater followed by UV irradiation and/or peracetic acid disinfection showed the potential for treatment of arctic wastewater.     

Influence of operational key parameters on the photocatalytic decolorization of Rhodamine B dye using Fe2+/H2O2/Nb2O5/UV system

The present research deals with the development of a new heterogeneous photocatalysis and Fenton hybrid system for the removal of color from textile dyeing wastewater as Rhodamine B (RhB) solutions by using Fe²⁺/H₂O₂/Nb₂O₅ as a photocatalytic system. The application of this photocatalytic system for the decolorization of dye contaminants is not reported in the literature yet. Different parameters like dye concentration, Nb₂O₅/Fe²⁺ catalyst amount, pH, and H₂O₂ concentration have been studied. The optimum conditions for the decolorization of the dye were initial concentration of 10 mg L^?1 of dye, pH 4, and Nb₂O₅/Fe²⁺ catalyst concentration of 0.5 g L^?1/50 mg L^?1. The optimum value of H₂O₂ concentration for the conditions used in this study was 700 mg L^?1. Moreover, the efficiency of the Nb₂O₅/photo-Fenton hybrid process in comparison to photo-Fenton alone and a dark Fenton process as a control experiment to decolorize the RhB solution has been investigated. The combination of photo-Fenton and Nb₂O₅ catalysts has been proved to be the most effective for the treatment of such type of wastewaters. The results revealed that the RhB dye was decolorized in a higher percent (78 %) by the Nb₂O₅/photo-Fenton hybrid process (Fe²⁺/H₂O₂/Nb₂O₅/UV) than by the photo-Fenton process alone (37 %) and dark Fenton process (14 %) after 120 min of treatment. Moreover, the Nb₂O₅ catalyst as a heterogeneous part of the photocatalytic system was demonstrated to have good stability and reusability.     

A simple method to prepare magnetic modified beer yeast and its application for cationic dye adsorption

The purpose of this research is to use a simple method to prepare magnetic modified biomass with good adsorption performances for cationic ions. The magnetic modified biomass was prepared by two steps: (1) preparation of pyromellitic dianhydride (PMDA) modified biomass in N, N-dimethylacetamide solution and (2) preparation of magnetic PMDA modified biomass by a situ co-precipitation method under the assistance of ultrasound irradiation in ammonia water. The adsorption potential of the as-prepared magnetic modified biomass was analyzed by using cationic dyes: methylene blue and basic magenta as model dyes. Optical micrograph and x-ray diffraction analyses showed that Fe₃O₄ particles were precipitated on the modified biomass surface. The as-prepared biosorbent could be recycled easily by using an applied magnetic field. Titration analysis showed that the total concentration of the functional groups on the magnetic PMDA modified biomass was calculated to be 0.75 mmol g^?1 by using the first derivative method. The adsorption capacities (q _m) of the magnetic PMDA modified biomass for methylene blue and basic magenta were 609.0 and 520.9 mg g^?1, respectively, according to the Langmuir equation. Kinetics experiment showed that adsorption could be completed within 150 min for both dyes. The desorption experiment showed that the magnetic sorbent could be used repeatedly after regeneration. The as-prepared magnetic modified sorbent had a potential in the dyeing industry wastewater treatment.     

Phytoaccumulation potentials of two biotechnologically propagated ecotypes of Arundo donax in copper-contaminated synthetic wastewater

An in vitro experiment was carried out to evaluate the phytoremediation potentials of two somatic embryo-derived ecotypes of Arundo donax—BL (American ecotype) and 20SZ (Hungarian ecotype)—of copper from synthetic wastewater. The two ecotypes were grown under sterile conditions in tubes containing a nutrient solution supplied with increasing doses of Cu (0, 1, 2, 3, 5, 10, and 26.8 mg L^?1) for 6 weeks. The translocation and bioaccumulation factors and removal rate were estimated. In general, increasing Cu concentration in nutrient solution slightly decreased root, stem and leaf biomass without toxicity symptoms up to 26.8 mg L^?1. Moreover, both ecotypes showed high Cu removal efficiency from aqueous solution. However, Cu removal rate ranged between 96.6 to 98.8 % for BL ecotype and 97 to 100 % for 20SZ ecotype. Data illustrated that both BL and 20SZ ecotypes may be employed to treat Cu-contaminated water bodies up to 26.8 mg L^?1.