Pickling Waste Liquor Research Articles

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.

Facile synthesis of schwertmannite@akaganeite core/shell nanostructure from pickling waste liquor: Formation mechanism and potential application

An environmentally friendly and low-cost synthesis of schwertmannite@akaganeite (Sch@Aka) core/shell nanostructure was achieved from hydrochloric pickling waste liquor (HPWL). The Sch@Aka nanostructure had a pincushion-like shape composed of radially well-aligned nanorods with an average length of about 250 nm and a mean diameter of about 60 nm. Trace SO42− ions played a key role in the formation of the Sch@Aka nanostructure. In the presence of Fe3+, Cl− and trace SO42− ions, schwertmannite was preferentially nucleated and then served as a core for akaganeite growth. The novel Sch@Aka nanostructure not only exhibited a higher adsorption capacity (43.0 mg g−1) for heavy metal Cr(VI) ions, but also delivered a larger reversible storage capacity of 1245 mA h·g−1 with Coulombic efficiency of close to 82% as the anode material in Li-ion batteries, indicating its potential application value.

Key role of FeO in the reduction of Cr(VI) by magnetic biochar synthesised using steel pickling waste liquor and sugarcane bagasse

Magnetic biochars with different iron content were synthesised and used for Cr(VI) removal. The species of iron oxides in that magnetic materials were Fe3O4, Fe2O3 and FeO, which were identified by various instruments. Scanning electron microscope indicated that the iron oxides distributed into the pores or on the surface of the biochar matrix, meanwhile, transmission electron microscopy illustrated that the exposed crystal planes of iron oxides in the magnetic biochar were difference. The maximum adsorption capacity of Cr(VI) by magnetic biochar was up to 71.04 mg/g and the adsorption capacity of Cr(VI) was positively correlated with iron content. Meanwhile, a series of experiments demonstrated that the FeO in the magnetic biochar was the key active component for the removal and reduction of Cr(VI). Finally, the mechanism analysis showed that the removal of Cr(VI) was attributed to the reduction, electrostatic adsorption and complexation, and reduction occupied a leading position. This study provides new insight into the role of iron oxides in magnetic biochar for the removal of Cr(VI).

Numerical Simulation on the Recovery Process of Acid Pickling Waste Liquor by Jet-Flow Pyrolysis

The direct discharge of hydrochloric acid pickling waste liquor from iron and steel enterprises seriously wastes resources and pollutes the environment. In this study, a Venturi jet-flow pyrolysis reactor was used to fabricate iron oxide and recover waste acid. Combustion, phase transformation, and gas-solidification reactions were numerically simulated in this independently-invented Venturi jet-flow pyrolysis reactor. Fluent software was combined with user-defined functions to describe the fluid flow characteristics and the distribution rules of each component during jet-flow pyrolysis in the reactor. Then, the velocity, temperature, and component concentration distributions in the reactor were analyzed. The results presented in this paper can provide a theoretical basis to study the pyrolysis treatment of hydrochloric acid pickling waste liquor, as well as data support for optimizing a Venturi jet-flow pyrolysis reactor.

Experimental and theoretical study on the behaviour of a pickling solution: The role of ferrous ions

Abstract The existence of ferrous ions plays an important role in the performance of pickling liquor as well as the recovery of hydrochloric acid from waste pickling liquor. The promotion mechanism and the interaction between ferrous ions and hydrogen chloride molecules have remained largely unsolved. In this research, the fundamental aspects of a simulated hydrochloric acid pickling solution with different concentrations of ferrous ions were experimentally and theoretically studied. The experimental results showed that the existence of ferrous ions in the pickling liquor effectively inhibited the volatilisation of hydrogen chloride from solution and that the inhibition of volatilisation enhanced with an increase in concentration of ferrous ions. To understand the interaction between ferrous ions and hydrogen chloride molecules, the structure and thermodynamic properties of possible hydration structures were obtained by using molecular simulation. The results showed that a new type of cluster, hydrogen chloride-ferrous ion-water, was formed in the presence of ferrous ions, which made the hydrogen chloride molecules in the pickling liquor more stable compared to the same condition without ferrous ions. The existence of ferrous ions in pickling liquor benefits the pickling process from an economic and environmental aspect.

Fenton-like catalytic degradation of tetracycline by magnetic palygorskite nanoparticles prepared from steel pickling waste liquor

Magnetic palygorskite nanoparticles (Pal@Fe3O4) were prepared from steel pickling waste liquor and used for Fenton-like catalytic degradation of tetracycline(TC). The results showed that TC can be efficiently removed in a wide pH range of 3–7. The degradation efficiency reached 72.9% within 60 min under neutral conditions. Moreover, since the amount of leached iron ions was <0.03 mg/L after each reaction, the catalytic effectiveness of Pal@Fe3O4 hardly changed after five cycles. The microstructure of Pal@Fe3O4 was investigated by SEM, TEM and STEM-EDS mapping, which showed that the Fe3O4 spherical nanoparticles were supported on the surface of the rod-shaped Pal. Moreover, the saturation magnetization of Pal@Fe3O4 was 44.11 emu/g, indicating that the catalyst could be easily separated by magnetic separation technology. Both hydroxyl radicals (•OH) and superoxide radicals (•O2−) were proven by electron spin resonance spectroscopy to be the dominant active species responsible for TC degradation. Four degradation products were identified by LC-MS/MS, mainly produced by the attack of the active radicals on the NC bond in the TC molecule.

Pyrolysis of different biomass pre-impregnated with steel pickling waste liquor to prepare magnetic biochars and their use for the degradation of metronidazole

In this study, Fenton-like catalysts (magnetic biochar) were synthesised by pyrolysis the different biomass pre-impregnated with steel pickling waste liquor. The results of degradation of metronidazole illustrated that the catalytic performance of magnetic biochar was significantly affected by biomass feedstocks. Electron spin resonance (ESR) and radical quenching experiments showed that the hydroxide radicals (OH) were the key reactive oxygen species responsible for the metronidazole removal. Levels of OH varied among different systems consistent with the removal of metronidazole. The activation of H2O2 by carbon-containing components and Fe species (Fe2O3 and Fe3O4) in magnetic biochar were confirmed to be less crucial to the degradation of metronidazole. Moreover, the Fe(II) (FeO) in magnetic biochar played the dominating role in degradation of metronidazole, and the Fe(II) content difference caused by biomass feedstocks was responsible for differences in the catalytic performance of different types of magnetic biochar.

Biomass waste components significantly influence the removal of Cr(VI) using magnetic biochar derived from four types of feedstocks and steel pickling waste liquor

Few studies have focused on the effects of biomass feedstocks on the structure–reactivity of magnetic biochar. In this study, four types of magnetic biochar were first prepared using steel pickling waste liquor (serving as iron salt) and sugarcane bagasse (SMBC), rice straw (RMBC), peanut shells (PMBC) and herb residue (HMBC). According to the Langmuir model, the maximum adsorption capacity of Cr(VI) by SMBC was 43.122 mg/g, which was approximately 1.298 times, 3.175 times and 3.677 times higher than that of RMBC, PMBC and HMBC, respectively. The mass balance of chromium indicated that Cr(VI) was removed mainly via reduction. However, the reduction capacity of Cr(VI) differed among the four types of magnetic biochar. The results of characterisations of those magnetic composites before and after reaction demonstrated that the Cr(VI) was electrostatically attracted to the surface of the materials. Consequently, most of the adsorbed Cr(VI) was reduced and the remainder of the Cr(VI) was complexed with CO groups in magnetic biochar. Further, the total iron in magnetic biochar, especially Fe(II), played a dominant role in the removal and reduction of Cr(VI). Finally, correlation analysis showed that the cellulose and ash in the biomass were the main factors that induced the differences in the magnetic biochar’s total iron content. Therefore, this study may provide a reference for the use of magnetic biochar to remove Cr(VI) from aqueous solutions.

Separation and recovery of copper from waste printed circuit boards leach solution using solvent extraction with Acorga M5640 as extractant

ABSTRACTWaste printed circuit boards (WPCBs) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using steel pickling waste liquor (SPWL) as the leaching agent. The leaching solution contains a variety of metals, especially iron, which will have an effect on the recovery of copper. Acorga M5640 (M5640) extractant with a kerosene diluent was used to recover copper from WPCBs leach solution, and the separation factor is adopted to analyze the effects of these metal ions. The effect of different parameters such as pH of aqueous phase, phase ratio (O/A), M5640 concentration, contact time as well as the concentration of H2SO4 as stripping reagent were investigated. Over 90.0% copper was extracted with pH 1.1, phase ratio (O/A) 1/1, M5640 concentration 16%, contact time 3 min at room temperature. For the stripping process, the 60 s contact time and 2.5 mol/L H2SO4 concentration are suitable with 90.0% stripping percentage of copper. Copper extraction isotherm accords with Langmuir isotherm equation and the results show that iron is the most influential metal ion for copper extraction, which will reduce the theoretical saturation of the extractant. The extractant M5640 has excellent reuse performance and can be recycled more than 10 times, which demonstrated M5640 has the industrial application value in the extraction of copper from WPCBs leach solution.

Treatment of paper mill wastewater using a composite inorganic coagulant prepared from steel mill waste pickling liquor

In this study, a waste pickling liquor from a steel mill, which is rich in iron and acid, was used as the main raw material to prepare a composite coagulant: polymeric ferric aluminum sulfate chloride (PFASC). The as-prepared PFASC was used, together with PAM, for the tertiary treatment of papermaking wastewater to decrease its COD and Chroma. The Results from FT-IR and XRD of PFASC, supported the conclusion that polymeric ferric aluminum hydroxide hydrates compounds/ complexes are formed in the synthesized PFASC. When applied to a waste water sample from a paper mill, PFASC, together PAM, leads to decreases in COD and Chroma by 65.3% and 71.2%, respectively (initial pH 7.5, 1 ml/L PFASC, 1.0 ppm PAM). The technology has been implemented at a paper mill, and the obtained results are consistent with those from the laboratory.

Degradation of nitrate and secondary pollution in drinking water by S-NZVI prepared from steel pickling waste liquor

In this study, degradation of nitrate in drinking water by nanoscale zero-valent iron prepared from steel pickling waste liquor(S-NZVI) was investigated. Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM) and Specific Surface Area Analyzer (BET) were used to characterize the properties of the synthesized nanoparticles. Effects of different parameters, such as S-NZVI dosage, initial nitrate concentration, and pH, on the denigration were conducted. The results showed that S-NZVI had the similar characteristic of the NZVI prepared by chemical agents. The experiments indicated that the slightly acid medium with the S-NZVI dosage of 2.8 g/L had a better removal effect of nitrate, and the high removal efficiency of 96% was observed after the reaction time of 2 h, which demonstrated it was feasible and effective to remove nitrate by S-NZVI. The kinetic studies indicated that the degradation rate of nitrate by S-NZVI followed the pseudo-first order kinetics. By analyzing the end-products of nitrate reduction, 94% of nitrate was converted into ammonia ions by S-NZVI and the others translated into a little amount of nitrite and nitrogen. It is a relatively easy and cost-effective method for nitrate removal, so S-NZVI has a great potential application in nitrate removal of drinking water. The ammoniac nitrogen pollution, the main product and second pollution from the denitrification by S-NZVI can be completely degraded by cation exchange resin. So the nitrogen pollution has been completely removed from drinking water polluted by nitrate.

Complex Process Monitoring Using KUCA With Application to Treatment of Waste Liquor

In this paper, a new nonlinear process modeling method called kernel uncorrelated component analysis (KUCA) is proposed. Several advantages of KUCA are summarized as follows. First, KUCA is superior to traditional data-driven modeling methods such as principal component analysis, independent component analysis, and so on, for it has no constraints on data distribution and data structure. In other word, it can be applied to modeling non-Gaussian and nonlinear process. Second, the proposed KUCA allows us to extract uncorrelated components (UCs) from observations directly without considering the second-order or higher order statistic, which is of low computational load. In addition, KUCA is applied to a numerical example to evaluate its performance of source signal separation. Finally, on the basis of KUCA, the corresponding processes monitoring scheme is developed, and the hot galvanizing pickling waste liquor treatment process is taken to evaluate the monitoring performance of the proposed methods. Experiment results demonstrate the feasibility of the proposed monitoring scheme.

Application of independent component analysis with semi‐supervised Laplacian regularization kernel density estimation

AbstractIn this study, fault detection and fault reconstruction methods are developed using matrix factorization of component vectors obtained with independent component analysis (ICA). Two monitoring statistics are used for fault detection in a detailed analysis of the ICA data model. A fault reconstruction technique is proposed that can determine the normal value and an estimate of the fault magnitude from the measurements. A semi‐supervised Laplacian regularization (SLR) kernel density estimation approach is introduced to determine the normal operating region, which can significantly reduce the false alarm rate. These methods are applied to a hot galvanizing pickling waste liquor treatment process (HGPWLTP) to evaluate the performance of the proposed approach. The test results show that the proposed approach has satisfactory performance.

A novel approach for recovery of metals from waste printed circuit boards and simultaneous removal of iron from steel pickling waste liquor by two-step hydrometallurgical method

Waste printed circuit boards (WPCBs) and steel pickling waste liquor (SPWL) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using SPWL as the leaching agent. A series of continuously domesticated bacteria were used for bioleaching and the bacterial strain was identified as Acidithiobacillus ferrooxidans (A. ferrooxidans) by 16S rDNA gene sequence analysis. The vast majority of the metals in WPCBs were recovered by two-step leaching, such as Cu, Pb, Zn, Sn, Al, Ni. Meanwhile, a large amount of iron was removed from SPWL, which greatly reduces the burden of the subsequent treatment. Pulp density and pH were optimized to achieve maximum recovery of copper and simultaneous removal of iron in bioleaching. It was found that the optimum conditions were pulp density 60 g/L and pH 0.5–1.0. Nearly 100% of copper was recovered and 51.94% of iron was removed under optimum conditions. The kinetic experiments showed that the rate of copper leaching was controlled by external diffusion rather than internal diffusion, because the acidic environment of the leachate prevented the formation of the precipitate and maintained it in a smaller size.

Uncorrelated component analysis on manifold for statistical process monitoring

A novel process modeling approach referred to as locally invariant uncorrelated component analysis (LIUCA) is proposed for the purpose of statistical process monitoring. The contributions are as follows: (1) LIUCA intends to find a part‐based representation subspace in which two data points are close to each other, if they are close in the k‐nearest neighbor graph; (2) LIUCA can exploit the geometrical structure of the data space, which will improve the algorithm's modeling performance in real‐world applications; (3) LIUCA‐based multivariate statistical process monitoring scheme is proposed. (4) In contrast to traditional process modeling algorithm such as principal component analysis, LIUCA imposes no restriction on data distribution. In addition, both a multivariate numerical example and a hot galvanizing pickling waste liquor treatment process are taken to evaluate the feasibility of the proposed process monitoring scheme. Experiment results demonstrate the effectiveness of the proposed method.

Enhanced nitrate removal by novel bimetallic Fe/Ni nanoparticles supported on biochar

In this study, a novel bimetallic iron/nickel nanoparticles supported on biochar (BC@Fe/Ni) was established to degrade nitrate pollution in water. The nanocomposite was prepared from steel pickling waste liquor and sugarcane bagasse, which are made at low cost. The particle sizes of the nanocomposite ranged from about 10 nm to 20 nm and its specific surface area (59.83 m2/g) was about 71% bigger than that of nanoscale zero valent iron prepared from steel pickling waste liquor (S-NZVI), which proved that biochar had an excellent dispersal effect on bimetallic iron/nickel particles. Without controlling the pH, high nitrate removal rates over 93% could be realized in nitrate concentrations below 50 mg/L. The results of batch experiments demonstrated that the kinetics curves fitted the pseudo-first-order reaction well. And it was also found that higher dosages of the nanocomposite, lower initial nitrate concentrations, and acid medium facilitated nitrate degradation. In addition, the observed pseudo-first order rate coefficient in nitrate (20 mg/L) degradation rate by 4 g/L of the bimetallic iron/nickel supported on biochar was 30% faster than that by 2 g/L the bimetallic iron/nickel nanoparticles, due to the existence of biochar. And it was 75% faster than that by 2 g/L the nanoscale zero valent iron due to the existence of both biochar and the nanoscale zero valent nickel catalyst. Furthermore, iron and nickel ion pollution occurred in the denitrification system with bimetallic iron/nickel nanoparticles but not in that with the bimetallic iron/nickel nanoparticles supported on biochar, due to the biochar’s adsorption. After denitrification by the bimetallic iron/nickel nanoparticles supported on biochar, most of nitrate turned into ammonia (17.04 mg/L) and there only was a small amount of nitrite (0.024 mg/L) with high nitrate removal rate (99.5%). And most of ammonia can be absorbed by cation exchange resin with finial ammonia concentration of 0.58 mg/L. At last, the concentrations of nitrate (0.24 mg/L), nitrite (0.021 mg/L), and total nitrogen (0.84 mg/L) were lowest in the nanocomposite system. Overall, the bimetallic iron/nickel nanoparticles supported on biochar exhibited clear advantages over bimetallic iron/nickel nanoparticles and nanoscale zero valent iron with respect to degrading nitrate efficiently, preventing iron and nickel pollution and removing ammonia pollution in combination with cation exchange resin.

Novel coprecipitation–oxidation method for recovering iron from steel waste pickling liquor

Waste pickling liquors (WPLs) containing high concentrations of iron and acid are hazardous waste products from the steel pickling processes. A novel combined coprecipitation–oxidation method for iron recovery by Fe3O4 nanoparticle production from the WPLs was developed in this study. An oxidation–reduction potential monitoring method was developed for real-time control of the Fe2+/Fe3+ molar ratio. The key coprecipitation–oxidation parameters were determined using the orthogonal experimental design method. The use of promoters greatly improved the Fe3O4 nanoparticle crystallinity, size, magnetization, and dispersion. X-ray diffraction patterns showed that the produced Fe3O4 nanoparticles were single phase. The Fe3O4 nanoparticles were approximately spherical and slightly agglomerated. Vibrating sample magnetometry showed that the Fe3O4 nanoparticles produced from the WPLs had good magnetic properties, with a saturation magnetization of 80.206 emu·g–1 and a remanence of 10.500 emu·g–1. The results show that this novel coprecipitation–oxidation method has great potential for recycling iron in WPLs.

Semi‐supervised kernel partial least squares fault detection and identification approach with application to HGPWLTP

AbstractIn this paper, fault detection and identification methods based on semi‐supervised Laplacian regularization kernel partial least squares (LRKPLS) are proposed. In Laplacian regularization learning framework, unlabeled and labeled samples are used to improve estimate of data manifold so that one can establish a more robust data model. We show that LRKPLS can avoid the over‐fitting problem which may be caused by sample insufficient and outliers present. Moreover, the proposed LRKPLS approach has no special restriction on data distribution, in other words, it can be used in the case of nonlinear or non‐Gaussian data. On the basis of LRKPLS, corresponding fault detection and identification methods are proposed. Those methods are used to monitor a numerical example and Hot Galvanizing Pickling Waste Liquor Treatment Process (HGPWLTP), and the cases study show effeteness of the proposed approaches. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Recovery of zinc from industrial waste pickling liquor

The constantly increasing global demand of zinc metal along with the decreasing zinc ore reserves has led to an upward trend of zinc production from secondary sources. Galvanizing industry generates byproducts and wastes containing zinc in the form of intermetallic compounds or oxides (zinc dust). One such byproduct, waste pickling liquor (WPL) is generated in galvanizing industry during the pickling of defective galvanized material. WPL contains Zn and Fe in ionic form and is discarded after neutralization. In the present work, chemical precipitation method is used to recover zinc from WPL; with an objective to retain maximum possible iron within the WPL solution. The effect of precipitating agent concentration, number of reactions steps, temperature and stirring speed were considered to determine process parameters for maximum zinc recovery. The iron rich WPL solution with negligible quantities of zinc is a valuable ingredient for production of red oxide pigment. Thereby, two products are obtained by adopting this technique: (i) Zinc rich precipitates and (ii) iron rich pickling liquor. X-ray diffraction (XRD) analysis of precipitates (heated at elevated temperature), shows that zinc oxide and zinc ferrite phases were formed from the zinc rich precipitates.

Recovery and application of heavy metals from pickling waste liquor (PWL) and electroplating wastewater (EPW) by the combination process of ferrite nanoparticles

Heavy metal contamination in wastewater poses a severe threat to the environment and public health. Magnetic iron-based materials are effective for heavy metal wastewater treatment, resources conservation, and recycling of metal ions. In the present work, two kinds of heavy metal wastewater were used to fabricate magnetically separable MnFe2O4 and CuFe2O4 as catalysts. The obtained catalysts were characterized by scanning electron microscopy, X-ray diffractometry, vibrating sample magnetometer, and X-ray photoelectron spectroscopy. Results showed that MnFe2O4 and CuFe2O4 MNPs could effectively activate peroxymonosulfate (PMS) to generate powerful sulfate radicals (SO4-⋅) for Rhodamine B (RhB) removal. More than 99% of RhB (10 mg/L) was degraded within 20 min using 0.4 g/L MnFe2O4 MNPs and 0.2 g/L PMS. The most effective pH for RhB degradation by PMS/WB-MnFe2O4 was 3. And under the condition of catalysts loading (0.40 g/L), dye concentration (10 mg/L), PMS = 0.2 g/L and T = 25°C, the stability and reusability of MnFe2O4 and CuFe2O4 MNPs was investigated. Recycled WB-MnFe2O4 MNPs showed strong activity in RhB degradation and its activity remained almost unchanged in eight cycles, while the activity of WB-CuFe2O4 MNPs dropped down after three cycles.