Pickling Waste Liquor Research Articles

Study on the preparation of Nano-Fe3O4 by steel pickling waste liquor and its effective removal of Cr (VI) from wastewater

In order to comprehensively treat and utilize steel pickling waste liquor (SPWL), this study used SPWL as raw material to prepare two different crystalline forms of Nano-Fe3O4 by co-precipitation and precipitation-oxidation methods, and investigated their removal effect on Cr(VI) in wastewater. The two kinds of Nano-Fe3O4 were characterized using SEM, XRD, and VSM, and the results showed that the Nano-Fe3O4 synthesized by the co-precipitation method has better properties. The two kinds of Nano-Fe3O4 were used to remove Cr(VI) in wastewater, the adsorption capacity could reach 38.38 mg/g and 15.83 mg/g, respectively. Five adsorption kinetic models and five isothermal adsorption models were used to study the adsorption mechanism of Fe3O4 on Cr(VI). The adsorption process of Cr(VI) by Nano-Fe3O4 was explained well using the pseudo-second-order and Freundlich isotherm model, and the results showed that the adsorption process mainly involved physical and chemical adsorption. Through the characterization analysis before and after the reaction, the removal mechanism of Cr(VI) by Nano-Fe3O4 prepared from SPWL is mainly attributed to electrostatic adsorption and reduction reaction. According to the market survey and analysis, the production cost is reduced by at least 58.33 % compared to that of Nano-Fe3O4 prepared using analytical purity in the market. Therefore, the preparation of Nano-Fe3O4 by steel pickling waste liquor provides an economical and effective way to remove heavy metal ions in wastewater.

FePO4 preparation and residue recycling by co-processing of steelmaking slag and steel pickling waste liquor: Comprehensive utilization of metallurgical wastes

To prepare FePO4 and to achieve resource utilization of metallurgical wastes, a collaborative treatment of P-bearing steelmaking slag and steel pickling waste liquor (SPWL) was proposed. The utilization of SPWL as a leachant for P separation from steelmaking slag facilitates P-removal residue recycling within steel plants, while also serving as a Fe source for the FePO4 preparation. In this study, the effects of synthetic SPWL with various Fe2+ (or Fe3+) contents and leaching parameters on the dissolution behavior of steelmaking slag were investigated. Moreover, the impacts of H2O2 oxidation and pH on the precipitation behavior of FePO4 from leachate were studied. It was found that increasing Fe2+ concentration in SPWL resulted in a marginal reduction in the P dissolution ratio; however, it was significantly influenced by the pH and solid/liquid ratio. Furthermore, the change in Fe3+ concentration within SPWL exhibited a conspicuous impact on the P dissolution ratio. After leaching, the residue containing massive Fe2O3, MgO, and MnO could be reused as a flux within the steelmaking process. The FePO4 precipitated predominantly at pH 2.0 ∼ 3.0, and the crude FePO4 product containing 42.6 % Fe2O3 and 35.8 % P2O5 was obtained, providing a new solution for the utilization of metallurgical wastes.

Insights into the adsorptive separation of iron from pickling waste acid: The overlooked role of FeCl3 species

Elucidating the dominant adsorption species of FeCln3−n is fundamental for precisely regulating the adsorption process and thus enhancing the management of waste pickling liquor. In this work, anion resin (D201) exhibits great adsorption for FeCl4−, also exhibits the unexpectedly high adsorption for neutral species FeCl3. The contribution of various iron species was quantitatively evaluated via Ion Species Contribution Evaluation (ISCE). The results illustrate that both FeCl3 and FeCl4− were the dominant species adsorbed by D201 resin and exhibited similar adsorption activities. Experimental and computational results indicate that the adsorption of FeCl4− is accompanied by the shedding of Cl on FeCl4− and FeCl3 recombines with the Cl on D201, which indicate that FeCl3 is an intermediate species in the FeCl4− adsorption process. Accordingly, FeCl3 was revealed to be critical species for iron adsorption in hydrochloric pickling liquor. The concentration of HCl (20 % w/w) required for FeCl3 was sufficient for the removal of iron compared with the higher concentration (25 % w/w) required for FeCl4−, which broadened the concentration boundary for HCl reuse. Our strategy serves for industrial iron removal from hydrochloric pickling liquor and results in 86 % reduction in the amount of hydrochloric acid during 100 days pilot-scale test.

Insights into the well-dispersed nano-Fe3O4 catalyst supported by N-doped biochar prepared from steel pickling waste liquor for activating peroxydisulfate to degrade tetracycline

The harmless and high-value added utilization of steel pickling waste liquor (SPWL) is a major challenge in the metallurgical advancement. Herein, well-dispersed nano-Fe3O4 (NF) composite with N-doped biochar as a spatial support (NF/0.5N3BC) is synthesized from SPWL and corncob, which has a large specific surface area (159.12 m2/g) and mesoporous structure. Besides, it exhibits excellent degradation efficiency (91.56%) and rate constant (0.042 min−1) of tetracycline (TC, 50 mg/L) by activating peroxydisulfate (PDS). Both free radicals and non-free radicals contribute to the TC degradation, among which the Fe species, defective edges, C = O, graphitic-N, and pyridinic-N are identified as the possible active sites. Particularly, N3BC cooperates with NF to form an internal electronic field to accelerate the Fe(III)/Fe(II) redox cycle and direct electron transfer process. Further, the possible degradation pathways are proposed based on DFT and HPLC-MS analysis, and the toxicity prediction results verify that NF/0.5N3BC + PDS system has an excellent TC degradation/detoxification ability. This study provided a novel strategy for high-value added utilization of SPWL and economically feasible treatment of TC-contaminated wastewater, so as to realizing the goal of “treating waste with waste”.

Simulation study of citric acid effects on pyrolysis of hydrochloric acid pickling waste liquor

During pyrolysis of hydrochloric acid pickling waste liquid in a Venturi Reactor from iron and steel enterprises, the reaction products agglomera ted and hindered product recovery. Addition of citric acid to materials at the inlet improved product distribution. In this paper, a numerical simulation of the combustion, phase change, and gas-solid chemistry involved in a citric acid-added pickling waste liquid was conducted. These results showed that citric acid added to the inlet resulted in a peak concentration of carbon dioxide (CO2) in the back half of the venturi throat, and some ferric oxide (Fe2O3) underwent a secondary reaction to afford ferroferric oxide (Fe3O4). As the addition of citric acid increased, the flow of Fe2O3 at the outlet first increased and then decreased, while the flow rate of Fe3O4 first decreased and then increased. When the ratio of citric acid was 7%, the flow rate of Fe2O3 was the smallest and the flow rate of Fe3O4 was the largest.

Experimental investigation of the particle growth mechanism and influencing factors during granulation process by pyrohydrolysis in fluidized bed

Particle growth kinetics during the pyrohydrolysis of pickling waste liquor in fluidized bed has an important influence on the metal oxide recovery. This study innovatively investigates the particle growth mechanism by combining granulation characteristics in fluidized bed and collision behavior between droplet and heated spherical particle, and then explores the effect of operating parameters on particle growth and powder properties adhered on the surface in the fluidized bed at 800 ℃. The results indicated that the particle growth mechanism was highly dependent on the bed temperature. When T < 100 ℃, it was mainly based on the direct droplet deposition on the surface; at 100 ℃< T < 300 ℃, droplet deposition and powder collision adhesion together promoted particle growth; when T > 300 ℃, the powder adhesion by inertia collision was dominant. The change in particle growth mechanisms was attributed to the liquid-solid interactions. The increasing particle temperature promoted rebound and breakup of droplets after impacting with the particles and then led to fine powder formation in the bed gaps. However, the increase of liquid viscosity was beneficial for the direct adhesion of droplets to the particle surface and accelerated particle growth. The results also found that operating parameters had a significant effect on the granulation characteristics. The coating layer thickness, powder size and porosity all increased with bed temperature. When the bed temperature is 800 ℃, the size of powder and bed particles both increased with the concentration of Fe3+ but decreased with the atomized gas velocity. However, the increase in liquid flow rate led to slower particle growth because of the increase in superheated vapor volume.

Process Optimization of Steel Pickling Waste Liquor Treated by Electrochemical Synthesis of Fe3O4

Process Optimization of Steel Pickling Waste Liquor Treated by Electrochemical Synthesis of Fe3O4

A comparative study on adsorption and catalytic degradation of tetracycline by five magnetic mineral functional materials prepared from steel pickling waste liquor

Palygorskite (Pal), bentonite (Bent), sepiolite (Sep), zeolite (Zeol), and kaolin (Kaol) were used with steel pickling waste liquor to synthesize magnetic palygorskite (Pal@Fe3O4), magnetic bentonite (Bent@Fe3O4), magnetic sepiolite (Sep@Fe3O4), magnetic zeolite (Zeol@Fe3O4), and magnetic kaolin (Kaol@Fe3O4), for adsorption and catalytic degradation of tetracycline (TC), respectively. Through the study of adsorption kinetics and adsorption isotherms, the maximum adsorption capacity of Pal@Fe3O4 to TC was 149.439mg/g, which was 1.239 times, 2.260 times, 3.161 times, and 3.448 times of Bent@Fe3O4, Zeol@Fe3O4, Kaol@Fe3O4, and Sep@Fe3O4, respectively. The kinetic study of tetracycline degradation demonstrated that the maximum reaction rate constant of Bent@Fe3O4/H2O2 system was K(obs) = 2.12 × 10-2min-1, which was close to that of Pal@Fe3O4/H2O2, Kaol@Fe3O4/H2O2 system, and was 2.000 times, 2.356 times, 2.650 times, and 4.711 times of Fe3O4/H2O2, Zeol@Fe3O4/H2O2, Sep@Fe3O4/H2O2, and H2O2 system, respectively. The results showed that Pal@Fe3O4 and Bent@Fe3O4 were more advantageous in the treatment of wastewater containing tetracycline, and efficient reuse of exhausted magnetic minerals and deep mineralization of organic pollutants were achieved by constructing an advanced oxidation system. The BET, VSM, SEM, XPS, XRD, and FTIR were used to characterize the five clay minerals before and after magnetic modification. It was speculated that the surface structure - OH groups of clay minerals might be significant factors influencing the adsorption performance of magnetic minerals on TC, and reduction ability of clay minerals to Fe3+ importantly affected the catalytic performance of magnetic minerals. The specific surface area and morphological structure of clay minerals both affected the adsorption and catalytic degradation of TC by the five magnetic minerals.

Recycling the steel pickling waste liquor to produce a low-cost material for immobilization of heavy metal(loid)s

This work aims to demonstrate the practicability of employing Iron (Fe)-manganese (Mn) binary oxide (FMBO) synthesized from pickling wastewater to immobilize arsenic (As(V)) and antimony (Sb(V)). Visual MINTEQ software was used to simulate the speciation of As(V) and Sb(V) under different pH values. The adsorption performance of FMBO for Sb(V) and As(V) were examined by batch experiments, the pH impact, sorption kinetics, sorption isotherms and the reuse of the adsorbent were investigated. The pH impact results demonstrated that the absorption capacity decreased dramatically as the pH value increased, the maximum adsorption capacities As(V) and Sb(V) were obtained at pH value of 4 as 95.24 and 147.1 mg/g, respectively. The kinetic results indicated that the pseudo-second order model could fit the kinetic data of Sb(V) and As(V) well. Equilibrium studies displayed that the adsorption of Sb(V) and As(V) on FMBO could be appropriately described by Freundlich model. Results of the binary adsorption indicated that Sb(V) exhibited ∼ 5% improvement for As(V) when the initial Sb(V) content raised from 0 to 500 mg/L, while As(V) showed a significant hindrance for Sb(V) adsorption. Moreover, utilization of FMBO could also effectively reduce the TCLP extractable and easy mobile As and Sb in contaminated soil, thus reducing their bioavailability. In view of the advantages of cost-effective, eco-friendly and excellent sorption performance, the steel pickling waste liquor-derived FMBO could be regarded as a promising amendment for remediating As and Sb contamination in environment. • A new low-cost adsorbent (FMBO) was prepared from steel pickling waste liquor. • FMBO exhibited an excellent performance for sorption of As(V) and Sb(V). • The existence of Sb(V) favor As(V) sorption, while As(V) showed opposite effect on Sb(V). • The FMBO could also effectively reduce the bioavailability of soil As and Sb.

Synthesis of nanosized nickel zinc ferrite using electric arc furnace dust and ferrous pickle liquor

Electric arc furnace dust (EAFD) and waste pickle liquor (WPL); two major side products of the steel industry with negative environmental impact were used for the synthesis of nickel zinc ferrite (NZF); the important magnetic ceramic material of versatile industrial applications. The structural and magnetic properties of the prepared material were examined which showed good magnetic properties (high saturation magnetization and low coercivity) compared with those synthesized from pure reagents. In the applied process, nano sized nickel zinc ferrite (NZF) with a composition of Nix(Zn + impurities)1−xFe2O4 (where x = 0, 0.25, 0.5, 0.75 and impurities of manganese, magnesium, and calcium were prepared using zinc-containing electric arc furnace dust (EAFD) and waste pickle liquor (WPL). The chemical compositions of the prepared samples were determined using X-ray fluorescence (XRF) analysis. The optimum acetic acid concentration for EAFD treatment was found 2% v/v that decreased Ca content of EAFD by 70.6% without loss of Fe and Zn. The structural and morphological characterization was done by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Field Emission Scanning Electron Microscope (FESEM) to confirm the formation of Ni–Zn ferrite nanoparticles and estimate the particle sizes. The maximum saturation magnetization (Ms) of 73.89 emu/g was achieved at 0.5 Ni content and the minimum coercivity of 2.55 Oe was obtained at 0.25 Ni content.

Magnetic biochar derived from rice straw and stainless steel pickling waste liquor for highly efficient adsorption of crystal violet

Reducing the preparation cost of magnetic biochar is necessary for its large-scale application as an adsorbent. In this study, stainless steel pickling waste liquor and rice straw were successfully applied to synthesize of magnetic biochar (SPWL-MBC). Several iron oxides adhered on the biochar matrix, mainly Fe3O4, Fe2O3 and FeO. SPWL-MBC exhibited superparamagnetism, and its specific surface area was 274.29 m2/g. The material was able to adsorb a model contaminant, crystal violet (CV), with a maximum adsorption capacity of approximately 111.48 mg/g. Adsorption mechanism analysis showed that iron oxides, π-π interaction, hydrogen bonding and electrostatic interaction were responsible for the adsorption of CV. The CV adsorption efficiency of SPWL-MBC remained 71.91% after three adsorption-regeneration cycles. These outcomes illustrate that the magnetic biochar prepared from stainless steel pickling waste liquor can effectively remove CV from wastewater.

Tunable synthesis of polyethylene polyamine modified lignin and application for efficient adsorption of Fe2+ in super acid system

In this study, a lignin-based adsorbent modified with epichlorohydrin and pentaethylenehexamine (LO-PEHA) was controllably synthesized via epoxidation and Mannich reaction to scavenge ferrous (Fe2+) ions in the super acidic solution. Various kinds of characterization were executed to investigate the structural morphological characteristics of the resulting adsorbent. The well-designed adsorbent showed a rich mesoporous structure with intricate channels. The ferrous ions entrapment by the adsorbent followed the Langmuir model with the maximum adsorption capacity of 862.9 mg/g at dosage of 0.05 g/20 mL under 298 K. And the adsorption kinetics complied with the pseudo-second-order model. The adsorbent possessed substantial adsorption efficiency (qe: 188.9–198.3 mg/g) for ferrous ions with sulfuric acid concentration of 5–250 g/L. It also demonstrated reliable performance with ferrous ions removal of 92.23% in the actual pickling waste liquor, slightly lower than that in the simulated system (99.24%). Furthermore, the mass transfer process of ferrous ions was predicted considerably well under the pore volume diffusion model (PVDM) with the effective pore volume diffusion coefficient of 4.5 × 10−10 m2/s, essentially commanded by the intraparticle resistance. Meaningfully, the tailor-made adsorbent is prospective as an efficient alternative for ferrous ions elimination, inspiring the future development of competent adsorbents for industrial effluent treatment.

Efficient metals removal from waste pickling liquor using novel task specific ionic liquids - classical manner and encapsulation in polymer shell

In the presented studies, extractant N′-(2-ethylhexyloxy)pyridine-4-carboximidamide (EH4IA), and its quaternary salts (4-[1-amine(2-ethylhexyloxyimine)]-1-propylpyridinium chloride (EH4IA-Cl) and 4-[1-amine(2-ethylhexyloxyimine)]-1-propylpyridinium bromide (EH4IA-Br)) were tested as the selective extractants of Zn(II) from waste pickling liquor, as well as after encapsulation, as sorbents enabling separation of Fe(II) and (III), Zn(II), and Pb(II). In the extraction study various factors affecting zinc(II) extraction, and its separation from Fe(II), such as NaCl, HCl, and the metals ions concentration in the aqueous feed solution, as well as structure and concentration of the extractant were analyzed. The metals sorption with the encapsulated extractants was found to be affected by the structure of the encapsulated ionic liquid, pH of the aqueous phase, shaking time, concentration of the metals ions, NaCl, HCl, and temperature of the process. The obtained results enabled to propose the scheme of waste pickling liquor treatment, and laboratory tests confirmed very high potential of the method and the selected to extraction and sorption stages extractant - EH4IA-Br.

High-efficiency leaching of valuable metals from saprolite laterite ore using pickling waste liquor for synthesis of spinel-type ferrites MFe2O4 with excellent magnetic properties

High-efficiency leaching of valuable metals from nickeliferous laterite ore for preparation of functional materials is one of the most important high-value utilization pathways. In this paper, facile preparation of multi-metal spinel-type ferrites (MFe2O4) from saprolite laterite ore after pickling waste liquor leaching process was proposed. The effects of pickling waste liquor leaching parameters including acid concentration, leaching temperature and time, liquid–solid ratio and iron ion concentration on leaching efficiency for Fe, Ni, Mg, Mn and Co from saprolite laterite ore and the molar ratio (RFe/M) of iron ions to divalent metal ions such as Ni2+, Mn2+, Mg2+, etc. in the leach liquors were systematically investigated. After complete leaching, spinel-type ferrites were synthesized from leach liquors and the influence of RFe/M and pH value as well Zn ion doping on phase compositions, morphological structure and magnetic performance of as-synthesized samples were also characterized and analyzed. Under the optimized leaching conditions, the leaching efficiency of Ni, Co, Mn, Fe and Mg could reach 93.2%, 90.8%, 94.3%, 95.5% and 85.3%, respectively. With the concentration of iron ions in pickling waste liquors increasing from 60 to 160 g·L−1, the RFe/M value increases from 1.88 to 4.32. The pH values for synthesis of spinel-type ferrites with high purity from leach liquors with RFe/M of 1.85 and 2.04 are 8.0 and 11.0, respectively, and the saturation magnetization Ms values of as-synthesized ferrites increase gradually with the increasing of pH value. Zn ions in pickling waste liquors could be doped and fixed in spinel-type ferrites to improve Ms values of as-synthesized ferrites, and the Ms value could reach the highest as 58.6 emu·g−1 when Zn ions doping amount is 0.4. Value-added utilization of pickling waste liquor and saprolite laterite ore could be realized by the proposed process. This paper might provide theoretical and technical support for low-cost synthesis of spinel-type ferrites from polymetallic resources.

Efficient activation of peroxymonosulfate and degradation of Orange G in iron phosphide prepared by pickling waste liquor

In this study, the low-cost preparation of iron phosphide by using pickling waste liquor as the initial material was performed through a two-step reaction. The degradation of Orange G was evaluated using iron phosphide coupled with peroxymonosulfate to construct a catalytic system. The removal efficiencies of Orange G and total organic carbon reached 97.4 and 58.4% at 60 min, respectively. Iron phosphide has dual-catalysis centers for the activation of PMS. Multiple free radicals (e.g., SO4•−, HO•, SO5•−, and O2•−) and singlet oxygen were involved in the pollutant degradation, of which sulfate radicals played the main role. The iron phosphide catalyst exhibited excellent recycling stability, and its catalytic efficiency reached 95% after five cycles. In summary, the Fe2P/PMS system—as a Fenton-like catalytic system—has certain advantages, including low cost, high efficiency, sufficient reusability, and good stability, all of which are favorable for its practical application.

Treatment of Simulated Steel Pickling Waste Liquor by Electrochemical Synthesis of Fe3O4

Due to the serious pollution and great harm of steel pickling waste liquor, the treatment of the waste liquor with high concentration of iron ion has been a problem in a lot of countries around the world. A simple electrochemical method is proposed for recovering iron from steel pickling waste liquor with graphite plates as electrodes. This study investigated the effects of reaction parameters on the concentration of residual total iron (TFe) in steel pickling waste liquor, including initial pH, reaction temperature, electrode distance, current density, and electrolytic time. Under the optimal reaction condition, the removal efficiency of TFe was 99.98%. The obtained precipitates were measured by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. It was found that the precipitates were high purity of Fe3O4 with small amount of γ-Fe2O3. This method will provide an effective and potential solution for resource recycling of steel pickling waste liquor.

Hierarchical bead chain ZnFe2O4-PEDOT composites with enhanced Li-ion storage properties as anode materials for lithium-ion batteries

In this study, we synthesized hierarchical bead chain ZnFe2O4-PEDOT composites with network of macroporous channels. For the first time, a ZnFe2(C2O4)3 precursor was prepared by co-precipitation using steel waste pickling liquor as a raw material, which was then sintered in air at 800 °C to yield monolithic ZnFe2O4. PEDOT was coated on the surface of ZnFe2O4 via in-situ polymerization of 3,4-ethylenedioxythiophene (EDOT). Electrochemical measurements showed that the 15 wt% PEDOT coated ZnFe2O4 composites (ZFPE-15) delivered a discharge capacity of 1510.5 mAh g−1 at 100 mA g−1 after 200 cycles, which was much larger than that of pure ZnFe2O4 (1055.9 mAh g−1), 10 wt% PEDOT coated ZnFe2O4 composites (ZFPE-10, 1264.2 mAh g−1), and 20 wt% coated ZnFe2O4 composites (ZFPE-20, 900.1 mAh g−1). Additionally, the ZFPE-15 composite exhibited a reversible capacity of 1004.7 mAh g−1, even at a large current density of 1 A g−1 after 200 cycles. These more desirable electrochemical properties can be attributed to the interconnected macroporous channels in the hierarchical bead chain skeleton, which can buffer volume expansion during circulation and inhibit particle agglomeration. Furthermore, the PEDOT nanoparticle coating produces a composite with greater mechanical strength and higher electrical conductivity, which provides higher electron transfer during the charge/discharge processes.

Direct preparation of polysilicic acid flocculant by using pickling waste liquor of metal plate

In this study, two kind of flocculants with high-performance, poly-silicate-ferrum (PSF) and poly-silicate-titanium-ferrum (PSTF) were prepared by using an industrial pickling waste liquid rich in titanium and iron as the main raw materials. The prepared PSF and PSTF were used to treat synthetic water at different pH values in order to explore the optimal pH range required for turbidity removal. The SEM and IR results of polymeric silicic acid indicate that the Ti and Si ratio can influence the morphology and bonding form of the flocculant. The characteristics of floc particle size, floc particle stability and settling time of the flocculant in the process of water treatment were studied in situ by laser particle size analyzer. The results show that the turbidity of synthetic water treated with PSF and PSTF can be decreased by above 99.86 % under the optimum using conditions (the initial turbidity of the synthetic water is 700 NTU).

FeCl3 coagulant production from waste pickle liquor using electrolysis

Pickling is a typical method used in a cold milling plant to remove impurities from hot rolled coil by immersing the coil in strong acidic solution. The spent acidic solution or waste pickle liquor (WPL) requires certain waste treatment before it can be disposed to environment because of its metallic ion and acid content. WPL contains a number of metallic ions that can be utilized as ferric chloride coagulant. The purpose of this paper is to evaluate the kinetics of Fe2+ oxidation into FeCl3 and the performance of the ferric chloride coagulant using the proposed electrolysis configuration. The electrolysis process was conducted in ambient condition with voltage 3 & 6 V, electrolysis time of 120 minutes, and addition of excess NaCl or HCl. The result shows that metal impurities in WPL and excess chlorine do not significantly affect the Fe2+ conversion. It can also be concluded that the optimum condition for electrolysis is using 6V of voltage, 90 minutes of electrolysis time, and excess chlorine at 0% stoichiometry which gave 60% conversion of Fe2+ in WPL. Due to the equilibrium between the Fe2+ dan Fe3+ which is formed during electrolysis process, the full conversion of Fe2+ is not possible yet, and the maximum conversion of Fe2+ is 60%. The presence of impurities in WPL is proven not affecting the Fe2+ conversion during the electrolysis process.

Effective degradation of tetracycline by magnetic palygorskite synthesized with different dosages of NaOH.

In the process of preparing magnetic palygorskite from waste pickling liquor of the steel industry, the dosage of NaOH will affect the properties of the magnetic palygorskite. The experimental results showed that magnetic palygorskite can be effectively prepared when NaOH dosage is between 255 and 330 g/L. Vibration sample magnetometry proved that different NaOH dosages can affect the saturation magnetization of magnetic palygorskite. The catalytic performance of five catalysts synthesized with different NaOH dosages hardly changed after five cycles of Fenton-like catalytic degradation of tetracycline (TC). The magnetic palygorskite prepared by this method had good catalytic performance even when the catalyst preparation conditions were magnified ten times, which can provide a reference for large-scale preparation of magnetic palygorskite.