Distribution and accumulation of selenium in wild plants growing naturally in the Gumuskoy (Kutahya) mining area, Turkey

Ni, Cr and Co Phytoremediations by Alyssum murale Grown in the Serpentine Soils Around Guleman Cr Deposits, Elazig Turkey

Serpentine soils containing high levels of nickel and other metals are particularly preferred by some plants that accumulate nickel in their bodies. In this study, the Ni, Co, and Cr accumulation capacities of A. murale grown in Guleman's serpentine soils were measured. In this respect, 12 A. murale and their soils were collected from the mining site and surroundings. Afterwards, the collected samples were measured in order to evaluate the translocation and accumulation amounts of Ni, Cr, and Co. For that, soil and plant samples were analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). The mean Ni concentrations in the soil, roots, and shoots of A. murale were measured as 2475, 7384, and 7694 mg/kg, respectively. The mean Cr concentrations in the soil, roots, and shoots of A. murale were measured as 742, 33, and 8.4 mg/kg while the mean Co concentrations of A. murale in the soil, roots, and shoots were 166, 10.2, and 23.5 mg/kg, respectively. Then, ECR and ECS values were calculated for Ni, Co, and Cr. The results indicated that A. murale grown in Guleman's serpentine soils may be helpful for the rehabilitation studies of mining soils contaminated by Ni and can be utilized for phytoextraction.

A holistic approach to soil contamination and sustainable phytoremediation with energy crops in the Aegean Region of Turkey

The objective of this current review article is to evaluate the current knowledge of the contaminated soil in the study area based on reports and the results of previous experimental studies in the literature and to discuss the feasibility of phytoremediation with biofuel production using energy crops. The results indicated that the soil contamination was related mainly to the thermal power plant and mining activities in Kütahya, high industrial activity in İzmir, heavy metal and radioactive pollution in Manisa and Muğla. Moreover, the sources of the contamination are geothermal resources and transportation in Aydın and Denizli, respectively. However, soil pollution in Afyonkarahisar and Uşak provinces has not been discussed due to a lack of detailed reports and data in the literature. Besides, energy crops such as Zea mays, Ricinus communis, and Gossypium hirsitum were identified as appropriate candidates for İzmir, Denizli, Manisa, and Aydın due to being resistant to the arid climate. In Muğla province, Eucalyptus grandis and Eucalyptus bicostata can be cultivated because of having adaptation to moderate climatic conditions. Ricinus communis and Helianthus annuus were determined to be very suitable energy crops for the phytoremediation of many heavy metals in Kütahya. The review promotes the development of economic, environmental, and social benefits to regain the contaminated areas through phytoremediation. The findings of the study are important for creating sustainable solutions for remediation of polluted soils in Turkey, as well as for shedding light on the process of establishing appropriate policies to make soils contaminated suitable for agriculture.

Kinetics, equilibrium and thermodynamics of dyes adsorption onto modified chitosan: a review

In view of promising sorption capacity, stability, biodegradability, cost-effectiveness, environmental friendly nature, regeneration and recycling ability, the chitosan (CS) based adsorbents are highly efficient for the sequestration of dyes. Since CS offers variable chemical structures and CS have been modified by incorporating different moieties. The CS composites with unique properties have been employed successfully for dye adsorption with reasonably high adsorption capacity versus other similar adsorbents. Modifications of CS were promising for the preparation of composites that are extensively studied for their adsorption capacities for various dyes. This review highlights the CS and its modification and their applications for the adsorption of dyes. The removal capacities of CS-based adsorbents, equilibrium modeling, kinetics studies and the thermodynamic characteristics are reported. Moreover, the FTIR, BET, SEM, TGA and XRD were employed for the characterization of CS modified adsorbents are also discussed. Results revealed that the modified CS is highly efficient and can be employed for the sequestration of dyes from effluents.

Kinetics, equilibrium and thermodynamics of dyes adsorption onto modified chitosan: a review

In view of promising sorption capacity, stability, biodegradability, cost-effectiveness, environmental friendly nature, regeneration and recycling ability, the chitosan (CS) based adsorbents are highly efficient for the sequestration of dyes. Since CS offers variable chemical structures and CS have been modified by incorporating different moieties. The CS composites with unique properties have been employed successfully for dye adsorption with reasonably high adsorption capacity versus other similar adsorbents. Modifications of CS were promising for the preparation of composites that are extensively studied for their adsorption capacities for various dyes. This review highlights the CS and its modification and their applications for the adsorption of dyes. The removal capacities of CS-based adsorbents, equilibrium modeling, kinetics studies and the thermodynamic characteristics are reported. Moreover, the FTIR, BET, SEM, TGA and XRD were employed for the characterization of CS modified adsorbents are also discussed. Results revealed that the modified CS is highly efficient and can be employed for the sequestration of dyes from effluents.

Evaluation of the metal(loid)s phytoextraction potential of wild plants grown in three antimony mines in southern China

Wild plant species from three deserted antimony (Sb) mine areas in southern China were collected to measure eight metal(loid)s. Antimony, As (arsenic), Cd (cadmium), Cr (chromium), Cu (copper), Ni (nickel), Pb (lead), and Zn (zinc) concentrations in plants and soil were analyzed. The soils of the mining area was weakly alkaline and contained toxic levels of Sb, As, Pb, Cd, and Zn. Many plant species in the area (40 species and 19 families) have no clear signs of toxicity. The plants were divided into three categories (high, moderate, and low tendency to accumulate metals) based on their (ratio [RT], bioaccumulation factor [BCF], translocation factor [TF]) values. The plants with a high accumulation tendency exhibited the high potential to absorb Sb from contaminated soil; therefore, they can be used for the remediation or phytoremediation of Sb-contaminated soil.

Kinetic and thermodynamic studies for evaluation of adsorption capacity of fungal dead biomass for direct dye

This study focuses on evaluation of degradation aptitude of white rot fungus (Coriolus versicolor) against Indosol Turquoise FBL dye. The outcome of numerous parameters including pH, temperature, carbon sources, nitrogen sources, C/N ratio and effect of dye concentration were studied. Maximum decolorization (99.896%) of Indosol Turquoise FBL was obtained by C. versicolor under optimized conditions. After three days, the maximum dye degradation (98%) was observed at pH 4 and 30 °C. Six carbon sources fructose, glucose, maltose, sucrose, rice bran and wheat bran were used and 96.66% degradation was observed by maltose at its optimum growth concentration (0.1 g/100 mL). Various nitrogen sources were employed for decolorization but ammonium nitrate decolorized dye up to 98.05%. The activity of three different enzymes laccase, Lignin peroxidase (LiP) and Manganese peroxidase (MnP) were calculated. The dead biomass of White rot fungus (WRF) was used for biosorption experiments. Maximum q (36 mg/g) was obtained at pH 2, at 30 °C using 0.05 g biosorbent. An increase in the q value was observed with increase in dye concentration. Freundlich adsorption isotherm and pseudo second order kinetics were followed by the data. It can be concluded that C. versicolor could be an efficient source for degradation of dyes from industrial effluents.

Experimental modeling, optimization and comparison of coagulants for removal of metallic pollutants from wastewater

Wastewater treatment coagulation is one of the most important physicochemical operations used in industry. The adsorption capability of marigold leaf powder, tea waste and ferrous sulfate was investigated for domestic and tannery effluents. These adsorbents significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. Maximum decrease in all the attributes was observed for 10 g of adsorbents application. All the adsorbents significantly affected the physiochemical attributes of both wastewaters. Similarly, maximum adsorption potential was observed in case of tea waste powder. Maximum decrease in all physiochemical attributes such as pH (15%), EC (21%), turbidity (54%), total dissolved solids (TDS; 36%), total suspended solids (TSS; 43%), total hardness (TH; 52%), chloride contents (59%) and phosphate contents (60%) was observed with the application of 10 g of tea waste. Regarding the heavy metals, maximum decrease for cadmium (Cd; 47%), lead (Pb; 81%), arsenic (As; 44%), copper (Cu; 75%), iron (Fe; 49%), chromium (Cr; 68%) and zinc (Zn; 64%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was tea waste > marigold leaf powder > ferrous sulfate. However, for the wastewater, the maximum effect of adsorbents was observed in case of domestic wastewater as compared to the tannery water. Based on these data, it is suggested that tea waste has maximum adsorption potential for the remediation of wastewater.

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Coagulation of Metallic Pollutants from Wastewater Using a Variety of Coagulants Based on Metal Binding Interaction Studies

In this study, different organic (moringa and neem leaf powder) and inorganic (alum) coagulants were used for the wastewater treatment. Results revealed that all the coagulants at various doses significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. The maximum decrease in all the attributes was observed when 10 g of coagulants were used. Similarly, maximum adsorption potential was observed in case of moringa leaf powder. Maximum decrease in all physiochemical attributes such as pH (13%), EC (65%), turbidity (75%), total dissolved solids (TDS; 51%), total suspended solids (TSS; 48%), total hardness (TH; 29%), chloride contents (66%) and phosphate contents (44%) was observed. Regarding the heavy metals, maximum decrease for Cadmium (Cd; 96%), Lead (Pb; 88%), Arsenic (As; 23%), Iron (Fe; 90%), Manganese (Mn; 96%) and Zinc (Zn; 48%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was moringa leaf powder > Alum > neem leaf powder. However, the maximum effect of coagulants was observed in case of textile wastewater as compared to the hospital wastewater. Based on the analyses, it is concluded that the moringa leaf powder has maximum adsorption potential for the remediation of wastewater.

Lead Remediation Using Smart Materials. A Review

The nanoparticles have been prepared and employed as excellent adsorbents for the sequestration of heavy metal ions and hazardous impurities from the aqueous media. The surface morphological, textural and structural properties of nanoparticles have been modified, which are capable and potentially useful for the remediation of metal ions. Several metals (oxides, doped, nanocomposites of Fe, Ti, Zn, SiO2, SiC, Mo, Co, Ni, Zr, Mn, Si, S, Al, Cu, Ce, graphene, CNTs) were reported an efficient adsorbents for the removal of lead (Pb) ions from aqueous media and polluted water. The present review focuses on different kinds of nanoparticles such as metal oxides, carbon based and host supported employed for removal of Pb ions under varying experimental conditions such as pH, temperature, contact time and concentrations. The preparation strategies, physicochemical properties and adsorption are also discussed. Based on studies, it was found that the smart materials are affective adsorbents for the purification of wastewater containing Pb ions and could possibly extended for the remediation of other heavy metal ions.

Selenium (Se) uptake and dynamic changes of Se content in soil-plant systems

In this study, we collected crop plants and associated soil samples and determined these for selenium (Se) content to analyze the uptake, enrichment, and translocation of Se in the different soil-plant systems of an agricultural production area, elucidate the dynamic mechanisms relating to Se content in plants and soil during different growth periods, and screen plants for high Se enrichment ability. Bioconcentration factor determinations indicated that the grains of rice have the strongest Se enrichment ability, followed by soybean and corn. Translocation factor analysis indicated that the grains of rice and corn have similar low translocation abilities for Se compared with soybean. Within the study area, the Se content in plants was closely related to the soil available Se content and varied considerably among different growth periods and plant organs. This study provides a theoretical basis for the development and utilization of local agricultural products.

Selenium analysis in waters. Part 1: Regulations and standard methods

Selenium is released into the aquatic environment through anthropogenic activities such as agricultural irrigation, coal mining, and metallurgical activities, where it acts as a reproductive toxin with negative effects on predatory fish and water fowl. Waterborne selenium concentrations are closely regulated worldwide, and various standardized methods are implemented by regulatory bodies to allow for the monitoring of selenium concentrations in different types of waters. Here, we discuss worldwide regulations relating to concentration limits of selenium in drinking, natural, and industrial waters. Focusing specifically on North America, we look at some standardized analysis methods and discuss the fact that many of these methods are not adequately sensitive to measure selenium in the concentrations outlined by the associated regulations for natural waters. We look in detail at the limitations of these methods with regards to both detection limits and interfering sample matrix components and establish the need for more sensitive and robust methods of analysis for regulatory compliance. This review is complemented by a second part (LeBlanc et al., 2018) where we discuss the state of selenium speciation analysis and importance of speciation data for decision makers in industry and regulators.

Fungal strains isolation, identification and application for the recovery of Zn(II) ions

Fungal biomass proves to be highly efficient for the treatment of wastewater as well as recovery of metal ions from wastewater. Present investigation was aimed to evaluate the efficiency of indigenous fungal isolates for the sequestration of Zn(II) ions aqueous solution. Among twenty five fungal isolates, Aspergillus oryzae SV/09 (AO SV/09), Aspergillus flavus NA9 (AF NA9) and Paecilomyces formosus DTO 63f4 (PF DTO-63f4) were identified by gene sequencing of ITS regions of the ribosomal DNA (rDNA). The AO SV/09, AF NA9 and PF DTO-63f4 showed promising efficiency for the biosorption of Zn(II) ions. Zn(II) ions adsorption was endothermic in nature and data fitted will to the Freundlich isotherm with correlation coefficients values of 0.99, 0.98 and 0.99 for AO SV/09, AF NA9 and PF DTO-63f4, respectively. Pseudo-second order kinetic model explained well the Zn(II) adsorption kinetic of Zn(II) ions onto biosorbents. The adsorbed Zn(II) ions were desorbed using HCl and 85.5, 75.3, 73.7 (%) Zn(II) ions were recovered from AO SV/09, AF NA9 and PF DTO-63f4 sorbents, respectively. The fungal biosorbents were successfully recycled up to five cycles. Based on sorption, recovery and regeneration, the application of fungal bio-sorbents for the sequestration and recovery of Zn(II) ions is suggested from wastewater and could possibly be extended for the recovery of other heavy metal ions from wastewater.

Batch versus column modes for the adsorption of radioactive metal onto rice husk waste: conditions optimization through response surface methodology

Batch and column adsorption modes were compared for the adsorption of U(VI) ions using rice husk waste biomass (RHWB). Response surface methodology was employed for the optimization of process variables, i.e., (pH (A), adsorbent dose (B), initial ion concentration (C)) in batch mode. The B, C and C² affected the U(VI) adsorption significantly in batch mode. The developed quadratic model was found to be validated on the basis of regression coefficient as well as analysis of variance. The predicted and actual values were found to be correlated well, with negligible residual value, and B, C and C² were significant terms. The column study was performed considering bed height, flow rate and initial metal ion concentration, and adsorption efficiency was evaluated through breakthrough curves and bed depth service time and Thomas models. Adsorption was found to be dependent on bed height and initial U(VI) ion concentration, and flow rate decreased the adsorption capacity. Thomas models fitted well to the U(VI) adsorption onto RHWB. Results revealed that RHWB has potential to remove U(VI) ions and batch adsorption was found to be efficient versus column mode.

Cu nanoparticles synthesis using biological molecule of P. granatum seeds extract as reducing and capping agent: Growth mechanism and photo-catalytic activity

In view of extended applications of nanoparticles, the nanoparticles synthesis is an extensive research field and green synthesis is one of the co-friendly methodologies. Plant extract mediated synthesis of nanoparticles has gained much attention in current decade. In current investigation, copper nanoparticles (CuNPs) were prepared using P. granatum seeds extract (biological molecules) from copper(II) chloride salt. The synthesized CuNPs were characterized by UV-vis spectroscopy, X-ray diffraction measurements (XRD), scanning electron microscopy (SEM), Energy Dispersive X- Ray Spectroscopy (EDX), Fourier transform infra-red spectroscopy (FTIR) and atomic force microscopy techniques. The CuNPs formation occurred through reduction of metal ions followed by nucleation. The size of the CuNPs was in the range of 40-80nm (average particle size was 43.9nm) with semi spherical shape and uniformly distribution. Photocatalytic activity was evaluated by degrading methylene blue dye (150mg/L) at various CuNPs doses (10mg/L-100mg/L). The synthesized CuNPs showed excellent PCA for the degradation of methylene blue (MB) under solar light irradiation and up to 87.11% degradation was achieved. The oxidative degradation mechanism for MB was proposed. In view of efficient PCA, the use of biological molecules of P. granatum seeds extracts for the synthesis of CuNPs.

Nickel nanoparticle synthesis using Camellia Sinensis as reducing and capping agent: Growth mechanism and photo-catalytic activity evaluation

Recently, the biosynthesis of nanoparticle attracted the attention of scientific community due to its simplicity, ease and eco-friendly nature. In the present study, Camellia Sinensis (C. Sinensis) leaves extract was employed for the synthesis of nickel nanoparticles (NiNPs). The fabricated NiNPs were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) and X-ray diffraction techniques. The photocatalytic activity (PCA) was evaluated by degrading crystal violet (CV) dye. The NiNPs size was in the range of 43.87-48.76nm, spherical in shape and uniformly distributed with magnetization saturation of 0.073 emu/g. The NiNPs showed promising PCA under solar light irradiation. At optimized conditions, up to 99.5% CV dye degradation was achieved. Results revealed that biosynthesis can be adopted for the synthesis of NiNPs in nano-size range since it is simple, cost effective and eco-friendly in nature versus physico-chemical methods.

Microalgae screening under CO2 stress: Growth and micro-nutrients removal efficiency

Algae are one of the promising agents for greenhouse gas reduction and biofuel production. Different technologies have been developed and introduced in last decades for algae growth. Algae plays a very imperative role in the aquatic ecosystem regarding CO₂ reduction and micro-nutrient removal. In present investigation, eight locally isolated (microalgae) strains and two pure strains were studied. The selected microalgae were grown under variable CO₂ concentration and CO₂ biofixation efficiencies along with micro-nutrient removal were monitored. Among selected strains, three strains (UMN266, UMN268 and UTEX 2714 showed adaptability up to 20% CO₂ concentration with high biomass production of 1.3, 1.4 and 1.21g/L, respectively, whereas UTEX 78 and UMN 230 growth was slow under high CO₂ concentration (20% CO₂). However, in step wise CO₂ feeding, the growth of UTEX 78 and UMN 230 improved considerably and up to 0.9 and 0.97 (g/L) biomasses were recorded, respectively. All algae strains showed high growth rate at 2% CO₂ feeding and nitrogen, phosphorus and ammonia removal from the simulated media were also significant. The fast-growing microalgae species tolerant up to 20% CO₂ concentration and could be used for flue gas mitigation and valuable products production. These results can contribute to understand the nature of CO₂ bio-fixation and microalgae could be a potential alternative for CO₂ fixation.

Bioaccumulation of thallium by the wild plants grown in soils of mining area

Gümüsköy Ag (As, Pb, and Tl) deposits are one of the largest silver deposits in the country and located about 25 km west of Kütahya, Turkey. This study investigated the accumulation and transport of thallium into 11 wild plants in soil of the mining area. Plant samples and their associated soils were collected from the field and Tl contents were measured with inductively coupled plasma mass spectroscopy (ICP-MS). The mean concentrations in the soil, roots, and shoots of the studied plants were, respectively, 170, 318, and 315 mg kg(-1) for Tl. The plants analyzed and collected from the studied area were separated into different groups based on enrichment coefficients of roots and shoots (ECR and ECS). The results showed that because of their higher ECR and ECS, the following could be good bioaccumulators: CY, IS, SL, and VR for Tl. Therefore, these plants can be useful for remediation or phytoremediation of soils polluted by Tl.