Magnetic Biochar Research Articles

Mixing Analysis of Bamboo and Natural Iron Sand as a Magnetic Material

This study aims to determine the magnetic properties of Fe3O4 synthesized from rope bamboo and natural iron sand. In this study, natural magnetic bio-char of bamboo and iron sand was synthesized by the co-precipitation method at a calcination temperature of 500oC. Then it was characterized through several tests, namely XRD and VSM. The results of the XRD test showed that the synthesis of natural bamboo + iron sand produced HKL peaks that were identical to Fe3O4 where these peaks were the peaks of magnetite and hematite. Magnetic properties were tested using VSM through a hysteresis curve with samples classified as soft magnets.

Mechanism of efficient magnetic biochar for typical aqueous organic contaminant combined-adsorption removal

Magnetic biochar adsorption is one of the most promising technologies for the treatment of organic pollutants in water, but there are problems of limited adsorption capacity and adsorption rate, and the adsorption mechanism of some small molecular organic pollutants needs to be further explored. A magnetic biochar (MBC) with high adsorption capacity and adsorption rate is successfully prepared by a modified chemical co-precipitation method, and methylene blue (MB) and acetone are used as representative pollutants. Through the combination of experiments and simulations, the adsorption mechanism of magnetic biochar on typical organic pollutants is explored. The results show that the magnets loaded on MBC are composed of Fe3O4 and FeO(OH) in a ratio of about 3:2, the saturation magnetization is 11.67 emu/g, and the adsorption capacities for MB and acetone are 645.08 mg/g and 59.42 mg/g, respectively. The adsorption processes are controlled by physical/chemical adsorption and followed pseudo-second-order kinetics. The chemical adsorption process mainly includes the polar effect contributed by oxygen-containing functional groups and the π-π interaction between MB molecules and biochar. This study can provide theoretical basis and optimization reference for the removal technology of organic pollutants in water.

Effect of Mn-based magnetic biochar /PS reaction system on oxidation of metronidazole

In order to fully exploit the potential of magnetic biochar-based persulfate (PS) systems, Mn was utilized to modify the magnetic biochar-based catalysts through impregnation-pyrolysis method. Taking metronidazole (MNZ), a typical antifungal drug, as the target contaminant, the reactivity of the synthesized magnetic biochar (MMBC) catalyst was evaluated. The degradation efficiency of MNZ in MMBC/persulfate system was 95.6%, which was 13.0 times higher than that in MBC/PS system. The characterization experiments confirmed the degradation of metronidazole by surface binding free radicals, the ·OH and 1O2 played the key role in remove of MNZ in the system of MMBC/PS. Physicochemical characterization, Fe(II) semi-quantitative analysis and masking experiments confirmed that the doping of MBC with Mn increased its Fe(II) content (43.0 mg/g), approximately 7.8 times higher than that of pristine MBC. The increase of Fe(II) content in MBC is the key reason to improve the optimization of MBC modified with Mn. Simultaneously, both Fe(II) and Mn(II) were the key components of PS activation by magnetic biochar. This paper presents a method to optimize the high efficiency of PS activation by magnetic biochar.

Facile synthesis of magnetic biochar from an invasive aquatic plant and basic oxygen furnace slag for removal of phosphate from aqueous solution

This study addresses the challenges of water pollution and solid waste treatment by presenting a two-step wet ball mill pyrolysis method for synthesizing magnetic biochar (MBC) from Water Hyacinth (Eichhornia crassipes) and basic oxygen furnace slag (BOFs) for adsorbing phosphate in water. The MBC showed excellent magnetic properties, with a coercivity of 259.3 Oe and a remanence of 0.552 emu˖g−1, and a high specific surface area (∼57.9 m2˖g−1) and micropore volume (0.070 m3˖g−1). The MBC had a rough surface and compact regular pore structure with a distribution of Fe3O4 and FeO. It exhibited a high phosphate adsorption capacity, reaching a maximum adsorption capacity of 39 mg˖g−1, and the adsorption process followed the pseudo-second-order kinetic model. The main adsorption mechanism was found to be chemical adsorption. The experiment investigated the loading efficiency of iron from BOFs and the mechanism of phosphate adsorption. This approach is cost-effective, environmentally friendly, and efficient, achieving the concept of “waste treating waste."

Effect of iron impregnation ratio on the properties and adsorption of KOH activated biochar for removal of tetracycline and heavy metals

The effect of iron impregnation ratio on magnetic biochars (MBCs) prepared by biomass pyrolysis accompanied by KOH activation has been less reported. In this study, MBCs were produced by one-step pyrolysis/KOH-activation of walnut shell, rice husk and cornstalk with different impregnation ratios (0.3–0.6). The properties, adsorption capacity and cycling performance for Pb(II), Cd(II) and tetracycline of MBCs were determined. MBCs prepared with low impregnation ratio (0.3) showed stronger adsorption capacity on tetracycline. The adsorption capacity of WS-0.3 toward tetracycline was up to 405.01 mg g−1, while that of WS-0.6 was only 213.81 mg g−1. It is noteworthy that rice husk and cornstalk biochar with an impregnation ratio of 0.6 were more effective in removing Pb(II) and Cd(II), and the content of Fe0 crystals on surface strengthened the ion exchange and chemical precipitation. This work highlights that the impregnation ratio should be changed according to the actual application scenarios of MBC.

Effective removal of tetracycline antibiotics from water by magnetic functionalized biochar derived from rice waste

The effective removal of tetracycline antibiotics (TCs) from water is of great significance and remains a big challenge. In this work, a novel magnetized biochar (magnetic functionalized carbon microsphere, MF-CMS) was prepared by the coupling hydrothermal carbonization and pyrolysis activation of starch-rich rice waste using ZnCl2 and FeCl3 as activators. As the MF-CMS dose was 2.0 g/L, the initial concentration of TCs was 100 mg/L, the removal rates of tetracycline, doxycycline, oxytetracycline, and chlortetracycline were 96.02%, 96.10%, 96.52%, and 85.88%, respectively. The best modeled on pseudo second order, Langmuir adsorption model, and intraparticle diffusion kinetic models suggested that both chemisorption and physisorption occurred in all removal processes, in which chemisorption dominated. TCs were efficiently adsorbed through the combined effects of pore filling, electrostatic attraction, π-π interactions, and complexation reactions of surface functional groups (such as γ-Fe2O3 and FeOOH). The removal rates of TCs after five cycles approximately decreased by 20%. And the cycling and metal ion release experiments of MF-CMS indicated that MF-CMS had good reusability, stability, and safety. The estimated cost of preparing MF-CMS is 5.91 USD per kg, and 1 kg of MF-CMS (consuming 8 kg of waste rice) can approximately treat 0.55 tons of TCs wastewater. Overall, the magnetic biochar derived from starch-rich rice waste as an adsorbent has promising and effective for the removal of TCs from water, but also provides a new idea for the resourceful treatment of solid waste.

Competitive adsorption of sulfamethoxazole and bisphenol A on magnetic biochar: Mechanism and site energy distribution

Competitive adsorption and complementary adsorption between emerging pollutants has been observed in multiple studies. Investigation of the preference of pollutants for different types of adsorption sites can provide a supplementary perspective for understanding complementary adsorption. In this study, the simultaneous adsorption of two typical emerging pollutants, sulfamethoxazole (SMX) and bisphenol A (BPA), on magnetic biochar (MBC-1) was investigated. The results showed that the modification with ferric chloride optimized the surface properties of biochar (aromaticity, hydrophobicity, and oxygen-containing functional groups, etc.), and helped to remove SMX and BPA through various interactions. The equilibrium adsorption capacity of the two adsorbents was inhibited by competitive adsorption in the mixed solute systems, which was due to the same adsorption mechanism. When pH = 7, the SMX and BPA adsorption mainly involved pore filling, hydrophobic effect, π-π EDA, and hydrogen bonding. In addition, electrostatic force, surface coordination, and ion exchange have also been proven to be related to the adsorption of SMX and BPA. In the co-adsorption system, BPA's competitive advantage might be due to its superior hydrophobicity, charge property, and molecular diameter. In the competitive adsorption experiment, the total adsorption capacity (Qi) of the competitive solute exceeded the adsorption inhibition (△Qi) of the main solute, indicating that the two solutes occupied their preferred adsorption sites, which confirmed the complementary adsorption phenomenon. Complementary adsorption can be explained by the preference of SMX and BPA for different types of adsorption sites. BPA preferentially occupied high-energy sites in the co-adsorption system, such as π-π EDA interaction, ion exchange, and surface coordination. At the same time, SMX tended to be removed by hydrophobic interaction and hydrogen bonding.

Physico-chemical characterization of walnut shell biochar from uncontrolled pyrolysis in a garden oven and surface modification by ex-situ chemical magnetization

The shells of walnuts (WS) are major refuse in the global fruits and nuts trade. This, otherwise discarded, lignin-rich material can be carbonized to biochar—a value-added product with environmental applications such as carbon sequestration, soil amelioration, and pollutant adsorption. These applications are dictated by structural and chemical characteristics of the biochar carbon. Conventional controlled pyrolysis (CPy) of biomass is cost-intensive and technically too complex for widespread adoption, especially in emerging economies. Here, walnut shell biochar (BWS0) is derived through uncontrolled pyrolysis (UCPy) in a pyrolysis oven and further hybridized as magnetic biochar through ex-situ chemical co-precipitation. The physico-chemical characteristics of biochar and its water-extractable fractions are comprehensively investigated to understand their carbon structure and environmental applicability. The sp2 amorphous carbon sequestered in BWS0 is 0.84 kgCO2/kgbiomass with a BET (N2) surface area of 292 m2/g and is comparable to biochar from CPy in terms of carbon structure. The polyaromatic hydrocarbons present are only trace amounts of naphthalene, biphenyl, and phenanthrene. The magnetization decreases porosity of BWS0 while greatly facilitating its separation from aqueous media. BWS0 is suitable for adsorption of cations (between pH 2.8 and 9.45) and hydrophobic pollutants with only 19 mg L−1 fouling from their intrinsic dissolved organic carbon. In combination with fast-release N, P fertilizers, BWS0 (C/N of 24.8) is suitable for application in hydrophilic soils at higher loading rates. The results suggest an avenue where WS biochar can also be prepared via UCPy for direct environmental applications. Future investigations into soil incubation and adsorption tests are recommended.Graphical abstract

Oxygen vacancies-enriched Fe-Cu bimetallic minerals-based magnetic biochar activated peroxydisulfate for durable sulfonamides degradation: pH-dependence adsorption and singlet oxygen evolution mechanism

The construction of oxygen vacancies (Vo) is a promising strategy for designing an efficient catalyst toward peroxydisulfate (PDS) activation. However, the unstable interface electron transfer and deactivation of Vo have been the bottleneck, and Vo-mediated PDS activation mechanisms remain vaguely interpreted. Herein, we innovatively synthesized a low-cost and durable Fe-Cu bimetallic mineral-based magnetic biochar with abundant Vo (Fe-CuFe2O4@BC). Fe-CuFe2O4@BC exhibited 6.64, 22.91, and 79.22-fold PDS activation rates for sulfamethazine (SMT) degradation (100%) and mineralization (91.58%) compared with Fe@BC, Cu@BC, and pristine BC, respectively. The outstanding performance of the Fe-CuFe2O4@BC/PDS system was ascribed to the Vo-induced sustainable electron transfer and singlet oxygen (1O2) generation, determined by chemical probes and kinetics study. pH-dependence adsorption of SMT dominated by the strengthened H-bonding and π–π EDA interaction was the key rate-limited step to PDS activation. Based on the surface investigation, electronic measurement, and Density functional theory (DFT) calculations, we proposed new insights into the electron-rich Vo and electron-deficient Cu co-induced PDS activation mechanism. Different from conventional perspectives, Vo preferentially activated PDS to generate 1O2, subsequently delocalizing and accumulating residual electrons from the Cu site. Simultaneously, metastable copper intermediates activated PDS through thermodynamically feasible reactions, promoting nano-confinement Vo-triggered 1O2 pathway. This study provides a new perspective for synthesizing Vo-rich catalysts and essentially deepens insights into nonradical mechanisms of refractory organics.

Magnetic Biochar Obtained by Chemical Coprecipitation and Pyrolysis of Corn Cob Residues: Characterization and Methylene Blue Adsorption.

Biochar is a carbonaceous and porous material with limited adsorption capacity, which increases by modifying its surface. Many of the biochars modified with magnetic nanoparticles reported previously were obtained in two steps: first, the biomass was pyrolyzed, and then the modification was performed. In this research, a biochar with Fe3O4 particles was obtained during the pyrolysis process. Corn cob residues were used to obtain the biochar (i.e., BCM) and the magnetic one (i.e., BCMFe). The BCMFe biochar was synthesized by a chemical coprecipitation technique prior to the pyrolysis process. The biochars obtained were characterized to determine their physicochemical, surface, and structural properties. The characterization revealed a porous surface with a 1013.52 m2/g area for BCM and 903.67 m2/g for BCMFe. The pores were uniformly distributed, as observed in SEM images. BCMFe showed Fe3O4 particles on the surface with a spherical shape and a uniform distribution. According to FTIR analysis, the functional groups formed on the surface were aliphatic and carbonyl functional groups. Ash content in the biochar was 4.0% in BCM and 8.0% in BCMFe; the difference corresponded to the presence of inorganic elements. The TGA showed that BCM lost 93.8 wt% while BCMFe was more thermally stable due to the inorganic species on the biochar surface, with a weight loss of 78.6%. Both biochars were tested as adsorbent materials for methylene blue. BCM and BCMFe obtained a maximum adsorption capacity (qm) of 23.17 mg/g and 39.66 mg/g, respectively. The obtained biochars are promising materials for the efficient removal of organic pollutants.

Removal of gatifloxacin by activated peroxymonosulfate using co-pyrolysis materials of water treatment residuals and biomass: Nonradical-dominated mechanisms enhanced by adsorption

Magnetic porous biochar derived from water treatment residuals and corn stalk (WTR-CS) was prepared by one-step pyrolysis method and applied for peroxymonosulfate (PMS) activation for gatifloxacin (GAT) removal. The results demonstrated that the adsorption and degradation efficiency of the WTR-CS/PMS system increased with the increasing pyrolysis temperature by changing their porosity, iron species and carbon configurations. WTR-CS obtained at 1000 °C (WTR–CS–1000) exhibited the best GAT removal effect, slight Fe leaching, strong stability and reusability. About 42.77% of GAT (40 mg L−1) was removed in the adsorption phase and 95.12% in total (90 min), accompanied by a 77% reduction in total organic carbon (TOC). The kinetic analysis demonstrated that adsorption was a key step in the overall catalytic process. Based on the quenching experiments, ESR and electrochemical tests, free radicals (SO4•-, ·OH and O2•-) and nonradical (1O2 and electron transfer) pathways jointly acted in the reaction, and nonradical pathway was dominant in the reaction. Four degradation pathways were proposed based on the intermediates detected by LC-MS, and the eco-toxicity of degradation intermediates was predicted by ECOSAR program. This study provides a new strategy for simultaneous iron-containing WTRs resource utilization and pollutant removal by synergistic adsorption and oxidative degradation.

Preferential, synergistic sorption and reduction of Cr(VI) from chromium–rhodamine B mixed wastewater by magnetic porous biochar derived from wasted Myriophyllum aquaticum biomass

Eradication of heavy metals and dyes simultaneously from wastewater is urgently needed to safeguard public and environmental health. In this study, magnetic porous biochar derived from wasted Myriophyllum aquaticum (MPMaB) was synthesized by KOH-activation and co–precipitation method to treat chromate and rhodamine B (RhB)-bearing wastewater. The KOH activation significantly improved the pore structure of biochar with a high specific surface area of 937.1 m2 g−1. The sorption performance of MPMaB for Cr(VI) and RhB in single and co-solutes conditions was evaluated. In single system, a pH-dependent sorption pattern for Cr(VI) by MPMaB was revealed and the estimated sorption capability reached 175.4 mg g−1, whereas the Langmuir-based sorption capacity of RhB was 175.4 mg g−1 pH-independently. MPMaB partially transformed Cr(VI) to less toxic Cr(III) (approximately 59.3%). Synergistic sorption of Cr(VI) with the coexistence of RhB was observed, where synergistic effect ranged from 119% to 527% depending on pH. For example, the sorption capacity of Cr(VI) on MPMaB, at pH 2, augmented from 175.4 mg g−1 (single system) to 208.3 mg g−1 (binary system). Preferential sorption of Cr(VI) was found and was further confirmed by the post-sorption of Cr(VI) (or RhB) by MPMaB pre-sorbed with RhB (or chromate). Chromate sorption mechanisms mainly include electrostatic interactions and complexation, while the sorption of RhB is ascribed to π–π interactions, pore filling and hydrogen bonding. Additionally, MPMaB showed excellent reusability and maintained high removal efficiency after 5 cycles. In short, MPMaB can efficiently treat chromium and dyes–containing wastewater as sustainable and environmentally friendly adsorbent.

ZIF-8 and humic acid modified magnetic corn stalk biochar: An efficient, magnetically stable, and eco-friendly adsorbent for imidacloprid and thiamethoxam removal

Neonicotinoids, ones of the most used pesticides extensively present in water environment, are hazardous to environment and human. Herein, a novel magnetic adsorbent ZIF-8-HA@MCSB is designed by modifying ZIF-8 and humic acid (HA) onto the surface of magnetic corn stalk biochar (MCSB) for removing imidacloprid (IMI) and thiamethoxam (THI) from water. MCSB has a superior adsorption performance among magnetic biochars (MBCs); the modification of ZIF-8 creating hierarchically porous structure and HA promoting the crystal growth of ZIF-8 can enhance its adsorption performance. Hence, ZIF-8-HA@MCSB exhibits the high maximum adsorption capacities for IMI (163.9 mg g−1) and THI (123.5 mg g−1). Meanwhile, the HA modification offers a protective shell for magnetic Fe3O4, which endows ZIF-8-HA@MCSB with distinguished magnetic stability. Even in pH = 2 solution, ZIF-8-HA@MCSB still possesses a saturation magnetization value of 13.07 emu g−1, which is beneficial for its separation and reuse. Especially, ZIF-8-HA@MCSB can be repeatedly used 5 times with high removal efficiencies (over 90%). Furthermore, the low Fe (less than 0.3 mg L−1 at pH ≥ 2) and Zn (less than 1.0 mg L−1 at pH ≥ 3) leaching concentrations in a wide pH range guarantee the environmental security of ZIF-8-HA@MCSB. And a promoting effect on wheat growth enables waste ZIF-8-HA@MCSB potentially to be fertilizer for crop production, which agrees with the sustainable concept. Therefore, the advantages of having high adsorption capacities for IMI and THI, resistant to acid, and friendliness to environment indicate that ZIF-8-HA@MCSB has a significant potential for real neonicotinoids removal. Novelty StatementIn this work, a novel magnetic adsorbent (ZIF-8-HA@MCSB) with the high adsorption capacities of IMI and THI is obtained by simply modifying ZIF-8 and humic acid (HA) onto the magnetic corn stalk biochar (MCSB) surface. Such a magnetic adsorbent has never been reported before. More importantly, compared with various modification methods to increase the adsorption capacity, there are few reports on concerning the acid resistance and environmental friendliness of magnetic adsorbents, especially the corresponding adsorption capacity also increases.

Ball-milled magnetic sludge biochar enables fast aerobic granulation in anoxic/oxic process for the treatment of coal chemical wastewater

Coal chemical wastewater (CCW) containing toxic and hazardous matters requires to be treated prior to discharge. Promoting the in-situ formation of magnetic aerobic granular sludge (mAGS) in continuous flow reactor process has a great potential for CCW remediation. However, long granulation time and low stability limit the application of AGS technology. In this study, Fe3O4/sludge biochar (Fe3O4/SC) with biochar matrix derived from coal chemical sludge were applied to facilitate the aerobic granulation in two-stage continuous flow reactors, containing separated anoxic and oxic reaction units (abbreviated as A/O process). The performance of A/O process was evaluated at various hydraulic retention times (HRTs) (42 h, 27 h, and 15 h). Magnetic Fe3O4/SC with porous structures, high specific surface area (BET = 96.69 m2/g), and abundant functional groups was successfully prepared by ball-milled method. Adding magnetic Fe3O4/SC to A/O process could promote aerobic granulation (85 days) and the removal of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and total nitrogen (TN) from CCW at all tested HRTs. Since the formed mAGS had high biomass, good settling ability, and high electrochemical activities, mAGS-based A/O process had high tolerance to the decrease of HRT from 42 h to 15 h for CCW treatment. The optimized HRT for A/O process was 27 h, at which Fe3O4/SC addition can result in the increase of COD, NH4+-N and TN removal efficiencies by 2.5 %, 4.7 % and 10.5 %, respectively. Based on 16S rRNA genes sequencing, the relative abundances of genus Nitrosomonas, Hyphomicrobium/Hydrogenophaga and Gaiella in mAGS accounting for nitrification, denitrification as well as COD removal were increased during aerobic granulation. Overall, this study proved that adding Fe3O4/SC to A/O process was effective for facilitating aerobic granulation and CCW treatment.

Highly efficient removal of methylene blue from aqueous solution by magnetic biochar prepared from hawthorn seeds

AbstractMagnetic biochar was prepared in one step with simultaneous activation and magnetization processes under CO2 atmosphere in the presence of a mixture of FeCl3·6H2O and hawthorn seeds as precursor. The magnetic biochar used as a potential adsorbent for the removal of methylene blue (MB) from aqueous solution was characterized by BET, FTIR, SEM and vibrating sample magnetometer. The produced magnetic biochar showed a high surface area of 489.166 m2/g, a pore size of 2.16 nm, a pore volume of 0.26 cm3 /g and a saturation magnetization of 29.84 emu/g. Batch adsorption studies were performed at different initial dye concentration, pH and temperature. The adsorption capacity of the magnetic biochar showed a good result for the adsorption of MB (147 mg/g). Of the two models used, the Langmuir isotherm fitted the equilibrium data better than the Freundlich isotherm. The kinetics study showed that the adsorption of MB was fitted better with pseudo‐second‐order kinetics model and the intra‐particle diffusion process was one of the main mechanisms controlling the adsorption rate. Moreover, thermodynamic parameters showed that the process of adsorption was endothermic and spontaneous. The experimental results showed that the magnetic biochar would be promising for practical wastewater treatment.

Dye Removal Characteristics of Magnetic Biochar Derived from Sewage Sludge: Isotherm, Thermodynamics, Kinetics, and Mechanism

Dye Removal Characteristics of Magnetic Biochar Derived from Sewage Sludge: Isotherm, Thermodynamics, Kinetics, and Mechanism

Analysis of the Effect of Modified Biochar on Saline–Alkali Soil Remediation and Crop Growth

To solve the problem of soil degradation in coastal saline–alkali land, three different types of biochar (rice straw biochar, magnetic biochar, and humic acid–magnetic biochar) were prepared to remedy the saline–alkali soil under different mixing ratios. The effects of biochar on the growth of crops in saline–alkali soil were explored through a pot experiment on Chinese cabbage. The experimental results showed that the soil leaching treatment combined with humic acid–magnetic biochar could effectively repair the coastal saline–alkali soil. After adding 5% humic acid–magnetic biochar, the content of soil organic matter was 33.95 g/kg, the water content was 13.85%, and the contents of available phosphorus and available potassium were 9.43 mg/kg and 29.51 mg/kg. After adding 5% humic acid–magnetic biochar, the plant height of Chinese cabbage was 9.16 ± 0.19 cm, and the plant germination rate reached 83.33 ± 5.54%. The incorporation of biochar could effectively increase the chlorophyll content and soluble protein content of pakchoi and reduce the soluble sugar content of pakchoi. The study analyzed the effect of different modified biochar on saline–alkali land restoration and crop growth and explored the action rule of hydrochloric acid magnetic biochar on saline–alkali land restoration, which has important practical value for improving coastal saline–alkali land.

Sewage sludge derived magnetic biochar effectively activates peroxymonosulfate for the removal of norfloxacin

As an undesirable by-product of the wastewater treatment plants (WWTPs), sewage sludge (SS) caused considerable stress on the normal operation of WWTPs, because of its expensive disposal costs. On the other hand, exploiting resource utilization of the residual SS seems to be an attractive approach to resolve this problem. In this study, SS was thermally converted into biochar catalysts (SBC) under oxygen-limiting conditions. By using peroxymonosulfate (PMS) as the chemical oxidant, norfloxacin (NOR) could be effectively removed and the reaction was significantly accelerated after the addition of SBC. Specifically, over 90% of NOR was eliminated by the SBC800/PMS process within 70 min. As evidenced by the comprehensive mechanistic investigations, 1O2 as well as electron-transfer regime primarily participated in the NOR degradation process, while radical species played minor roles. More importantly, the endogenous iron substances endowed SBC with magnetic properties, making the efficient separation of SBC from water available. Eventually, the possible intermediates were tentatively identified by liquid chromatography-mass spectrometry and the corresponding degradation pathways were proposed. Overall, this research developed a novel method to achieve the remediation of NOR-contaminated water and elimination of the potential risks of SS simultaneously.

Superefficient separation of Th(IV) and U(VI) by lignin-derived magnetic biochar via competitive adsorption mechanism

Thorium (Th) and uranium (U) separation remains a huge challenge due to their high similarity in chemical behavior. In this study, lignin-derived magnetic biochar (AL-Fe/BC), which can provide functional sites for adsorbing Th(IV) and U(VI), was synthesized for the selective extraction of Th(IV) from the binary U(VI)-Th(IV) matrix. Characterizations results confirm the successful zero-valent iron loading, and the AL-Fe/BC exhibited a developed polyporous structure, high surface area, stable crystallinity, high defects degree, and advantageous magnetic feature of expedient recovery from water without energy consumption. The optimist AL-Fe/BC-800 showed an outstanding adsorption capacity with a maximal Th(IV) uptake of 2000 mg/g, and a small absorption of 3 mg/g of U(VI) (Th(IV) = 180 mg/L, U(VI) = 20 mg/L, AL-Fe/BC-800 = 0.05 g/L). Moreover, the separation factor of Th(IV) from the Th(IV)-U(VI) matrix reached 90,000 even concomitant with high a concentration of co-existing ions. The active adsorption sites on AL-Fe/BC-800, such as COOH, C-OH, C=O, pyridinic N, graphitic N, and pyrrolic N, exhibited a stronger binding affinity with Th(IV) than U(VI), achieving selective Th(IV) adsorption via a chemisorption process on the basis of competitive adsorption. In summary, AL-Fe/BC-800 is a potential adsorbent in industrial application for the superefficient separation of Th(IV) and U(VI) with high-performance magnetic recovery, promoting the sustainable development of nuclear industry, especially considering the necessary development of Th(IV) fuel.

Synthesis of magnetic rice husk biochar and its application in the adsorption of Ni(II) from aqueous solutions

Synthesis of magnetic rice husk biochar and its application in the adsorption of Ni(II) from aqueous solutions