Use of three types of magnetic biochar in the removal of copper(II) ions from wastewaters (original) (raw)
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Journal of Engineering
This study evaluates the effectiveness of magnetic biochar (Fe2O3-EC) derived from water hyacinth in the removal of Cu+2 and Zn+2 from aqueous solution. Fe2O3-EC was prepared by chemical coprecipitation of a mixture of FeCl2 and FeCl3 on water hyacinth biomass followed by pyrolysis. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDX). Batch adsorption studies on the effects of temperature, biosorbent dosage, contact time, and initial metal ion concentration were carried out. Fe2O3-EC exhibited optimum contact time, biosorbent dosage, and pH values of 65 min, 1.2 g, and 6, respectively. Fe2O3-EC exhibited strong magnetic separation ability and high sorption capability. Metal ion adsorption onto the biochar conformed to the Langmuir isotherm. Kinetic studies revealed that the adsorption process followed pseudo-second-order model. The calculated thermodynamic parameter...
International Journal of Environmental Analytical Chemistry, 2020
The aim of the current research is to eliminate the Cu(II) ions from aqueous solution using biochar, namely sulphuric acid-modified Annona reticulata seeds (SMARS). The removal process followed the Freundlich and pseudo-first-order models. At optimum conditions, Langmuir adsorption capacity of the SMARS for Cu(II) ions was calculated as 561.1 mg/g. The results of this work indicate that the adsorption was feasible, spontaneous and exothermic, which was controlled by film diffusion. An adsorber has been designed based on Freundlich model. Desorption results indicate that 0.2 N of the hydrochloric acid solution provides the maximum elimination of heavy metals from the Cu(II) ions loaded adsorbent. The column influencing parameters like Cu(II) ions concentration, bed height and flow rate have been experimented. The best operating condition for removal of Cu(II) ions by SMARS in column mode of operation has been recorded as flow rate = 5 mL/min, bed height = 8 cm, adsorbent amount = 16 g, solution pH = 6.0 and at the temperature = 30°C. The column experimental data have been characterised by applying Bed Depth Service Time and Thomas models. The results indicate that the SMARS has exceptional adsorption behaviour in the elimination of heavy metals from the aqueous solution.
Journal of Chemistry, Environmental Sciences and its Applications
Due to industrialization and increasing population, wastewater treatment has become a big challenge.There are numerous techniques such as ion-exchange, adsorption, membrane filtration, coagulation, flocculation, floating and electrochemical approach developed for the remediation of contaminants from wastewater. But, now it is necessary to develop an approach which should has high efficiency, less expensive and environmental friendly, so that limitation of existing techniques can be overcome. Recent developments of biochar have attracted the researchers into this area. Different methods are discovered to synthesized biochar for the removal of pollutants from wastewater. In this review, biochar are elaborated and critically discussed which have reported for the removal of metallic pollutants present in waste water.
Science of The Total Environment
Sustainable methods to produce filter materials are needed to remove a variety of pollutants found in water including organic compounds, heavy metals, and other harmful inorganic and biological contaminants. This study focuses on the removal of Cu(II) from copper aqueous solutions using non-activated char derived from the pyrolysis of mixed municipal discarded materials (MMDM) using a new heat pipe-based pyrolysis reactor. Adsorption experiments were conducted by adding the char to copper solutions of varying concentration (50-250 mg/L) at a constant temperature of 30°C. The effect of pH on copper adsorption onto the char was also investigated in the range of pH 3 to 6. Copper removal using the char was found to be heavily dependent on pH, adsorption was observed to decrease below a pH of 4.5. However, the initial copper concentration had a little effect on the sorption of copper at high concentration solutions (above 100 mg/L). Overall, the biochar showed an effective copper adsorption capacity (4-5 mg/g) when using copper solutions with a concentration below100 mg/L and pH N4.5. Copper removal using the char tended to follow the pseudo second order kinetic model. Langmuir isothermal model was shown to be the closest fitting isotherm using the linearized Langmuir equation. However, the variety of feedstock used to produce the char led to a variation in results compared to other studies of more specific feedstocks.
The Science of the total environment, 2017
Despite the excellent sorption ability of biochar for heavy metals, it is difficult to separate and reuse after adsorption when applied to wastewater treatment process. To overcome these drawbacks, we developed an engineered magnetic biochar by pyrolyzing waste marine macro-algae as a feedstock, and we doped iron oxide particles (e.g., magnetite, maghemite) to impart magnetism. The physicochemical characteristics and adsorption properties of the biochar were evaluated. When compared to conventional pinewood sawdust biochar, the waste marine algae-based magnetic biochar exhibited a greater potential to remove heavy metals despite having a lower surface area (0.97m(2)/g for kelp magnetic biochar and 63.33m(2)/g for hijikia magnetic biochar). Although magnetic biochar could be effectively separated from the solution, however, the magnetization of the biochar partially reduced its heavy metal adsorption efficiency due to the biochar's surface pores becoming plugged with iron oxide p...
Investigations of Heavy Metal Ion Sorption Using Nanocomposites of Iron-Modified Biochar
Magnetic biochar nanocomposites were obtained by modification of biochar by zero-valent iron. The article provides information on the impact of contact time, initial Cd(II), Co(II), Zn(II), and Pb(II) ion concentrations, dose of the sorbents, solution pH and temperature on the adsorption capacity. On the basis of experiments, it was found that the optimum parameters for the sorption process are phase contact time 360 min (after this time, the equilibrium of all concentrations is reached), the dose of sorbent equal to 5 g/dm 3 , pH 5 and the temperature 295 K. The values of parameters calculated from the kinetic models and isotherms present the best match to the pseudo second order and Langmuir isotherm models. The calculated thermodynamic parameters ΔH 0 , ΔS 0 and ΔG 0 indicate that the sorption of heavy metal ions is an exothermic and spontaneous process as well as favoured at lower temperatures, suggesting the physical character of sorption. The solution of nitric acid(V) at the concentration 0.1 mol/dm 3 was the best acidic desorbing agent used for regeneration of metal-loaded magnetic sorbents. The physicochemical properties of synthesized composites were characterized by FTIR, SEM, XRD, XPS and TG analyses. The point characteristics of the double layer for biochar pH PZC and pH IEP were designated.
ACS omega, 2020
Fe-modified biochars have been widely used in removal of Cr(VI) from water due to the resulting modified surface functional groups and magnetization property. However, few studies have synthetically investigated modification methods and synthesis parameters on the improvement of the removal efficiency of Cr(VI) by Fe-modified biochars. Herein, 10 types of corn straw-based magnetic biochars were produced using pre-modification and post-modification methods with various modifier ratios, and the highest heating temperature (HHT). Cr(VI) removal results suggest that the removal efficiency of pre-modified biochars ranged from 50.7 to 98.6%, which was much higher than that of post-modified (6.6−21.6%) and unmodified biochars (0.4−7.6%). The effect of synthesis methods on Cr(VI) adsorption was in the following order: Fe-modification method > modifier ratio > HHT. The adsorption kinetics and isotherm results of three types of pre-modified biochars were well fitted with the pseudo-second-order model (R 2 > 0.99) and the Langmuir adsorption model (R 2 > 0.99), respectively, indicating the surface homogeneity of the premodified biochars and unilayer chemisorptions of Cr(VI). Characterization results show that iron oxides or zerovalent iron particles were successfully deposited onto the surface of biochars and magnetism was introduced. A good Pearson correlation (r = −0.9694) between the removal efficiency and pH value in modified biochar suggests that the lower pH value may offer more positive charges and promote electrostatic attraction. Therefore, the dominant mechanism for enhanced Cr(VI) adsorption on pre-modified biochar was electrostatic attraction, resulting from its distinguished acidity nature. Our findings provide new insights into the high-efficiency removal of Cr(VI) onto Fe-modified magnetic biochars and will benefit future design of more efficient magnetic biochars.
Synthesis of Magnetic Biochar for Efficient Removal of Cr(III) Cations from the Aqueous Medium
Advances in Materials Science and Engineering, 2019
Porous biochars obtained from coniferous woods, and magnetic biochars based on them, which showed high sorption properties when extracting Cr(III) from aqueous solutions (from 0.005 to 0.0125 mol/L), were studied. The adsorption properties of the magnetic biochar are compared with the initial biochar. It has been established that the preparation of materials by the method of pyrolysis and subsequent treatment in a plasma reactor makes it possible to bring the samples under study into a number of promising adsorbents for the extraction of chromium from aqueous solutions.
Journal of Inorganic and Organometallic Polymers and Materials, 2020
Removal of heavy metals from water by biochar is necessary and benefit for human life and environmental protection. In this study, biochar from sludge (SB), cow dung (DB), corn stalk (CB) and willow branches (WB) were synthesized and activated by potassium hydroxide (KOH), and these biochars were used as adsorbent to remove divalent cadmium ion (Cd(II)) from water. The materials were further characterized by using N 2-sorption, scanning electron microscopy (SEM), elemental analysis, thermal gravity and differential thermal gravity (TG/DTG) and fourier transform infrared spectroscopy (FTIR). It found that external surface area of biochar had significant effect on the adsorption of Cd(II). Batch adsorption experiments were performed to investigate the effects of various parameters, including initial pH value, adsorbent dosage, concentration of Cd(II) and adsorption time. The results showed that CB had a better adsorption ability to remove Cd(II) from water than the other biochars. The pseudo-second-order and pseudo-first-order kinetics models were introduced to study the adsorption kinetics of Cd(II) by CB. The Freundlich model and Langmuir model were both fit for the experimental isotherm data. The maximum adsorption capacity of 40 mg/g was obtained by CB according to the experimental isotherm data by Langmuir model.