A new biosorbent based on Nostoc commune (NC) cyanobacteria, chemically modified with NaOH (NCM), has been prepared, characterized and tested as an effective biomass to remove Pb(II) in aqueous ...media. The adsorption capacity of NCM was determined to be qsub.e = 384.6 mg gsup.−1. It is higher than several other biosorbents reported in the literature. Structural and morphological characterization were performed by FTIR, SEM/EDX and point zero of charge pH (pHsub.PZC) measurements. NCM biosorbent showed more porous surfaces than those NC with heterogeneous plates including functional adsorption groups such as OH, C = O, COOsup.−, COH or NH. Optimal Pb(II) adsorption occurred at pH 4.5 and 5.5 with a biomass dose of 0.5 g Lsup.−1. The experimental data of the adsorption process were well fitted with the Freundlich-isotherm model and pseudo-2nd order kinetics, which indicated that Pb(II) adsorption was a chemisorption process on heterogeneous surfaces of NCM. According to the thermodynamic parameters, this process was exothermic (∆Hsup.0 < 0), feasible and spontaneous (∆Gsup.0 < 0). NCM can be regenerated and efficiently reused up to 4 times (%D > 92%). NCM was also tested to remove Pb (%R~98%) and Ca (%R~64%) from real wastewater.
This study investigated the potential of biochar as a sustainable material for waste utilization and carbon sequestration in soil. Biochar was prepared from cow manure (CM) and applied to the soil. ...Biochar was processed by subjecting CM to various temperature ranges (400 CMB400, 550 CMB550, and 700 °C CMB700) under nitrogen gas (allowed to flow to restrict oxygen), with residence time set to 3 h. The characteristics of the biochar produced at each temperature were analyzed. The experiment was conducted for approximately 15 weeks with the laboratory temperature maintained between 24 and 26 °C. The growth rate of plants was obtained by measuring their length weekly, starting 4 weeks after crop establishment. CMB550 exhibited the highest specific surface area (117.57 msup.2 gsup.−1) and well-distributed pore size; therefore, it was mixed with the soil at a specific ratio and put in pots for the planting of Salicornia herbacea L. (glasswort) in the laboratory. The results demonstrated that adding biochar to soil increased plant growth and that the biochar could store organic carbon. In addition, an investigation of heavy metals demonstrated that samples with biochar had lower heavy metal concentrations in glasswort than those without because of the potential of biochar to adsorb heavy metals. By interacting with heavy metal ions in soil solution, the reactive sites and functional groups on the surface of biochar immobilize them and lessen their potentially detrimental effects on plant growth. Overall, biochar has the potential to be a valuable resource for waste management and environmental improvement.
To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups ...of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P < 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T.sup.1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P < 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma.
UV mutagenesis has long been known to improve bacterial strains in their physiological capacity. In the current study, we used the UV mutagenesis approach to increase the PGPR characteristics of a ...pre-characterized metal-tolerant PGPR strain Bacillus sp. strain SR-2-1/1 (KY315919), with the objective of increasing the physiological outcome of its PGPR traits in vitro and post inoculation on wheat plants. After UV irradiation, the results implied a substantial in vitro increase in the phosphate solubilization and ammonia production of two selected mutant strains (Msub.1 and Msub.2) as compared to the wild-type strain SR-2-1/1; however, the ACC deaminase enzyme activity was completely lost in the mutant strains, which were originally present in the wild-type strains. However, the UV mutagenesis did not affect the taxonomy of these mutant strains. Moreover, the mutant strains Msub.1 and Msub.2 survived in the rhizosphere of wheat plants up to 30 days at an optimum (approximately 7-7.5 Log CFU/mL of rhizosphere soil) population density. The fresh and dry biomass, as well as root and shoot length, of wheat plants inoculated with one of the mutant strains Msub.2 were significantly higher than in the wheat plants inoculated with wild-type strain SR-2-1/1. The overall results imply that the resulted mutant Msub.2 was a physiologically competent PGPR strain, which could be tested in field experiments as an inoculum.
The present study was conducted to quantify the heavy metals cadmium, lead, copper, chromium, nickel, and zinc in the bivalve mollusk concha prieta (Anadara tuberculosa) using inductively coupled ...plasma optical emission spectroscopy (ICP-OES). This research aims to identify whether the bioaccumulated content of heavy metals exceeds the maximum limits established by various public health bodies such as the ONU, FAO, Codex Alimentarius, EEC, and NHI. Samples of the species were collected randomly from three locations in Puerto El Morro, Playas Municipal Market, and La Libertad Seafood Market in the Gulf of Guayaquil. Thirty-three soft tissue samples of Anadara tuberculosa were evaluated, and the values quantified in mg/kg were in the following order: Zn > Cu > Cd > Ni > Cr > Pb.
This study aims to investigate the vegetative buds from Picea abies (spruce), naturally found in a central region of Romania, through a comprehensive analysis of the chemical composition to identify ...bioactive compounds responsible for pharmacological properties. Using HPLC/derivatization technique of GC-MS and quantitative spectrophotometric assays, the phenolic profile, and main components of an ethanolic extract from the buds were investigated. The essential oil was characterized by GC-MS. Moreover, the antioxidant activity with the DPPH method, and the antimicrobial activity were tested. Heavy metal detection was performed by graphite furnace atomic absorption spectrometry. The main components of the alcoholic extract were astragalin, quercetin, kaempferol, shikimic acid, and quinic acid. A total content of 25.32 ± 2.65 mg gallic acid equivalent per gram of dry plant (mg GAE/g DW) and of 10.54 ± 0.083 mg rutin equivalents/g of dry plant (mg RE/g DW) were found. The essential oil had D-limonene, α-cadinol, δ-cadinene, 13-epimanool, and δ-3-carene as predominant components. The spruce vegetative buds exhibited significant antioxidant activity (IC50 of 53 μg/mL) and antimicrobial effects against Staphylococcus aureus. Furthermore, concentrations of heavy metals Pb and Cd were below detection limits, suggesting that the material was free from potentially harmful contaminants. The results confirmed the potential of this indigenous species to be used as a source of compounds with pharmacological utilities.
In this study, quaternary MgYsub.2Osub.5@g-Csub.3Nsub.4 nanomaterials were produced using a simplistic ultrasonic power technique in the presence of an organic solvent, and their capability to ...abolish Cu (II) from an aqueous solution was evaluated. As validated by powder X-ray diffraction, the synthesized nanomaterials possessed excellent crystallinity, purity, and tiny crystalline size. According to BET and TEM, the nanomaterials with high porosity nanosheets and perfect active sites made Cu (II) removal from water treatment feasible. At a pH of 3.0, the MgYsub.2Osub.5@g-Csub.3Nsub.4 displayed good Cu (II) adsorption capability. The Cu (II) adsorption adhered to the Langmuir adsorption model, with an estimated theoretical maximum adsorption aptitude of 290 mg/g. According to the kinetics investigation, the adsorption pattern best fitted the pseudo-second-order kinetics model. Depending on the FTIR results of the nanocomposite prior to and after Cu (II) uptake, surface complexation and ion exchange of Cu (II) ions with surface hydroxyl groups dominated the adsorption of Cu (II). The MgYsub.2Osub.5@g-Csub.3Nsub.4 nanomaterials have great potential as adsorbents for Cu (II) removal due to their easy manufacturing process and high adsorption capacity. Additionally, the reuse of MgYsub.2Osub.4@g-Csub.3Nsub.4 nanomaterials was tested through the succession of four adsorption cycles using HNOsub.3. The result showed the good stability of this material for mineral pollution removal.
A mesoporous Zr-G-Csub.3Nsub.4 nanomaterial was synthesized by a succinct-step ultrasonication technique and used for Cusup.2+ ion uptake in the aqueous phase. The adsorption of Cusup.2+ was examined ...by varying the operating parameters, including the initial metal concentration, contact time, and pH value. Zr-G-Csub.3Nsub.4 nanosorbent displays graphitic carbon nitride (g-Csub.3Nsub.4) and ZrOsub.2 peaks with a crystalline size of ~14 nm, as determined by XRD analysis. The Zr-G-Csub.3Nsub.4 sorbent demonstrated a BET-specific surface area of 95.685 msup.2/g and a pore volume of 2.16 × 10sup.−7 msup.3·gsup.−1. Batch mode tests revealed that removing Cu (II) ions by the mesoporous Zr-G-Csub.3Nsub.4 was pH-dependent, with maximal removal achieved at pH = 5. The adsorptive Cusup.2+ ion process by the mesoporous nanomaterial surface is well described by the Langmuir isotherm and pseudo-second-order kinetics model. The maximum adsorption capacity of the nanocomposite was determined to be 2.262 mol·kgsup.−1 for a contact time of 48 min. The results confirmed that the fabricated mesoporous Zr-G-Csub.3Nsub.4 nanomaterial is effective and regenerable for removing Cusup.2+ and could be a potent adsorbent of heavy metals from aqueous systems.
Abstract
Here we study the effect of an additional interfacial spin-transfer torque, as well as the well-established spin–orbit torque and bulk spin-transfer torque, on skyrmion collections—group of ...skyrmions dense enough that they are not isolated from one another—in ultrathin heavy metal/ferromagnetic multilayers, by comparing modelling with experimental results. Using a skyrmion collection with a range of skyrmion diameters and landscape disorder, we study the dependence of the skyrmion Hall angle on diameter and velocity, as well as the velocity as a function of diameter. We show that inclusion of the interfacial spin-transfer torque results in reduced skyrmion Hall angles, with values close to experimental results. We also show that for skyrmion collections the velocity is approximately independent of diameter, in marked contrast to the motion of isolated skyrmions, as the group of skyrmions move together at an average group velocity. Moreover, the calculated skyrmion velocities are comparable to those obtained in experiments when the interfacial spin-transfer torque is included. Our results thus show the significance of the interfacial spin-transfer torque in ultrathin magnetic multilayers, which helps to explain the low skyrmion Hall angles and velocities observed in experiment. We conclude that the interfacial spin-transfer torque should be considered in numerical modelling for reproduction of experimental results.
There are global concerns about heavy metal (HM) contamination in soils, which in turn has produced an increased demand for soil remediation. Biochar has been widely documented to effectively ...immobilize metals in contaminated soils and has received increasing attention for use in soil remediation. Here, we review recent progresses in understanding metal-biochar interactions in soils, potential risks associated with biochar amendment, and application of biochar in soil remediation in China. These recent studies indicate that: (1) the remediation effect depends on the characteristics of both biochar and soil and their interactions; (2) biochar applications could decrease the mobility/bioavailability of HMs in soils and HM accumulation in plants; and (3) despite its advantages, biochar applications could pose ecological and health risks, e.g., by releasing toxic substances into soils or by inhalation of biochar dust. Research gaps still exist in the development of practical methods for preparing and applying different biochars that target specific HMs. In the future, the long term effects and security of biochar applications on soil remediation, soil organisms and plant growth need to be considered.
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•The metal-biochar interactions and mechanisms in soils were reviewed.•Potential risks associated with biochar amendment were discussed.•Cases of biochar application in soils in China were summarized.•Long term effects of biochar on soil remediation need further investigation.
The remediation of heavy metal contaminated soils by biochar in China was reviewed, including metal-biochar interactions and mechanisms, its application risk and status.
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