Main Metal Research Articles

Classified processing of different rice bran fractions according to their component distributions

SummaryRice grains were obtained from two Chinese provinces (Hubei and Guangxi) and then their rice bran was abraded into four equal fractions by weight from outside to inside. The component distributions in these four fractions were then investigated. The contents of total lipid‐soluble antioxidant showed no significant difference between rice bran from the Hubei province and the Guangxi province. But the content of total water‐soluble antioxidant was 1690.20 ± 86.40 mg kg−1 for rice bran from the Hubei province, significantly higher than those from the Guangxi province (1014.67 ± 71.09 mg kg−1). Obvious differences between four rice bran fractions or two provinces were proved by principal component analysis (PCA). Lipase activities decreased significantly from outer fractions to inner fractions, and lipids mainly distributed in three outer fractions. The essential element contents decreased significantly, but a main heavy metal element (Pb) in cereal increased significantly to 0.36 mg kg−1 from outer fractions to inner fractions, which was just slightly below the upper limit of Chinese Standard (0.40 mg kg−1). Although protein contents had no significant difference in four fractions, the amino acid compositions were quite different. In summary, different fractions of rice bran had different compositions, which could provide guidance for the classified processing of rice bran.

A Comprehensive Recovery Process for Selective Separation and Enrichment of Copper, Zinc and Iron Minerals from a Polymetallic Ore and the Adsorption Mechanism of Collector Z-200

A comprehensive recovery process for the selective separation and enrichment of copper, zinc and iron minerals from a polymetallic ore was developed, which consisted of copper flotation, zinc flotation, and iron magnetic separation, and the adsorption mechanism of the copper collector Z-200 (O-isopropyl-N-ethyl thionocarbamate) was also studied in this work. The contents of the main valuable metallic elements of Cu, Zn and Fe in the ore were respectively 0.61%, 1.68% and 14.17%, and they mainly existed as chalcopyrite, sphalerite and magnetite, whose dissemination relationship was complex. Under the optimal conditions of this process, the recoveries of Cu, Zn and Fe in their respective concentrates reached 86.1%, 87.6% and 77.8%, and their grades were separately 20.31%, 45.97% and 63.39%. This process realized the selective separation and beneficiation of copper, zinc, and iron minerals from the ore, and had promising industrial application prospects. The adsorption configuration analysis demonstrated that the steadiest adsorption configurations of Z-200 on the surfaces of chalcopyrite, sphalerite and magnetite were the simultaneous adsorption of carbonyl S together with the O atom. Compared with sphalerite and magnetite, Z-200 was more prone to adsorb on the chalcopyrite surface. The Mulliken charge population and bond length analyses manifested that Z-200 chemically adsorbed on the chalcopyrite surface by forming a normal covalent bond and a back donation covalent bond, and the normal covalent bond played a leading role. The chemisorption of Z-00 was supported by the FTIR spectrum analysis result.

Study of the Layer-Type BST Thin Film with X-ray Diffraction and X-ray Photoelectron Spectroscopy

In the present paper, results of X-ray photoelectron studies of electroceramic thin films of barium strontium titanate, Ba1−xSrxTiO3 (BST), composition deposited on stainless-steel substrates are presented. The thin films were prepared by the sol-gel method. A spin-coating deposition of BST layers with different chemical compositions was utilized so the layer-type structure of (0-2) connectivity was formed. After the deposition, the thin-film samples were heated in air atmosphere at temperature T = 700 °C for 1 h. The surfaces of BST thin films subjected to thermal treatment were studied by X-ray diffraction. X-ray diffraction measurements confirmed the perovskite-type phase for all grown thin-film samples. The oxidation states of the elements were examined by the X-ray photoelectron spectroscopy method. X-ray photoelectron spectroscopy survey spectra as well as high-resolution spectra (photo-peaks) of the main metallic elements, such as Ti, Ba, and Sr, were compared for the layer-type structures, differing in the deposition sequence of the barium strontium titanate layers constituting the BST thin film.

The characteristics of chemistry test items on nationally-standardized school examination in Yogyakarta City

AbstractThis study aimed to describe the characteristics of chemistry test items in Nationally Standardized School Examination or Ujian Sekolah Berstandar Nasional (USBN), consisted of discrimination index, difficulty index, and question reliability. The data was collected by using documentation of the answers of 194 students. The type of research was descriptive exploratory with quantitative and qualitative approaches. Quantitative data analysis was performed by using classical test theory approach and item response theory with 1 logistical parameter. Meanwhile, qualitative data analysis was conducted in order to describe the items that were categorized as difficult and bad categories. The results showed that according to classical test theory, USBN Chemistry item test had an average level of difficulty of 0.57 which was categorized as moderate. Regarding to the discrimination index, the average of different test power obtained were equal to 0.146, and belonged to the good category. Based on the item response theory, the average of difficulty index of -0,00086 was categorized as moderate. The results of the estimated reliability of the questions amounted to 0.48 included in the moderate category. The results of the qualitative analysis showed that the items which belonged to difficult category were the items on salt hydrolysis material, acid-base titration, the concept of periodicity, manufacture and use of chemical compounds according to classical test theory. Meanwhile, according to the theory of response, items which belonged to difficult category were found in acid-base titration material, the solution colligative phenomenon, and the concept of periodicity of the main metal elements.

Effect of main inorganic metal elements in Panax ginseng field soil on the photodegradation of fluazifop-p-butyl.

The widespread use of pesticides contributes to their existence in the environment. The compounds with photocatalytic activity in environmental matrixes play a significant effect on the photodegradation of pesticides. In order to clear the photolysis effects of the main characteristic inorganic metal elements in the of Panax ginseng field soil on fluazifop-p-butyl, a series of tests were carried out. The obtained results indicated that Mn2+ and Sn+ exhibited a significant photosensitization on the ultraviolet photodegradation of fluazifop-p-butyl. Also the high content of VO3- and Mo7O246- in the photolysis system showed a photoquenching on fluazifop-p-butyl, but the low content is a photosensitive effect. However, in the photolysis system, as the concentration of Co2+ and Li+ increases, the photoquenching effect on fluazifop-p-butyl becomes obvious, and no photosensitization at any tested concentration of them.

Main group metal elements for ambient-condition electrochemical nitrogen reduction

Electrocatalytic N2 reduction under ambient-condition is considered to be the most appealing strategy to the conventional Haber-Bosch process for synthetic ammonia to alleviate greenhouse emissions and reduce environmental pollution, mainly powered by renewable energy. Recent years, rapid advances have been gained in this attractive research field, and numerous electrocatalysts have been exploited. However, its conversion efficiency is still far behind the requirement of industrial applications owing to the breakage of the N≡N triple bond, which is an energetically challenging kinetically complex multistep reaction and the strong competing reaction of hydrogen evolution reaction. Recently, main group metal-based catalysts have been demonstrated promising application prospect for ammonia production, significantly boosting their further application in this field. However, a comprehensive review of main group metal-based catalysts towards electrochemical ammonia production applications is still lacking. In this review, the fundamentals of N2 reduction, such as the reaction pathways, the reaction potential and the challenges of N2 reduction have been comprehensively discussed. And then, the role, mechanism, and effect of each main group element-based catalysts used for N2 reduction (Li, K, Al, Ga, Sn, Sb, Bi, and their compounds) are systematically summarized. Finally, several state-of-the-art strategies to promote their NRR catalytic performance, as well as the existing problems and prospects are put forward. This review is expected to guide the design and establishment of more efficient electrocatalytic N2 reduction systems based on main group metal elements in the future.

Superior Hydrogen Sorption Kinetics of Ti0.20Zr0.20Hf0.20Nb0.40 High-Entropy Alloy

High entropy alloys (HEAs) are composed of multiple main metal elements and have attracted wide attention in various fields. In this study, a novel Ti0.20Zr0.20Hf0.20Nb0.40 HEA was synthesized and its hydrogenation properties were studied, including sorption thermodynamics and hydrogen absorption/desorption kinetics. The maximum hydrogen absorption capacity was 1.5 H/atom at 573 K. X-ray diffraction (XRD) analysis indicated that the crystal structure of Ti0.20Zr0.20Hf0.20Nb0.40 HEA transformed from body-centered cubic (BCC) to body-centered tetragonal (BCT) with increasing hydrogen content, and to face-centered cubic (FCC) after hydrogen absorption to saturation. As a multi-principal element alloy, the Ti0.20Zr0.20Hf0.20Nb0.40 HEA possesses unique hydrogen absorption characteristics. The hydrogen absorption platform pressure rises gradually with the increase of the hydrogen absorption amount, which is caused by multiple kinds of BCT intermediate hydrides with consecutively increasing c/a. The full hydrogen absorption of the Ti0.20Zr0.20Hf0.20Nb0.40 HEA was completed in almost 50 s, which is faster than that of the reported hydrogen storage alloys in the literature. The experimental results demonstrate that the Ti0.20Zr0.20Hf0.20Nb0.40 HEA has excellent kinetic properties, unique thermodynamic hydrogen absorption performance, as well as a low plateau pressure at room temperature.

From binary to multinary copper based nitrides – Unlocking the potential of new applications

• Diversity of synthetic strategies towards copper nitrides as bulk or thin films. • Overview of conditions that allow to control the morphology and particle size. • Structural diversity of multinary copper nitrides and their emerging applications. This review summarizes the current knowledge on the chemistry of binary copper(I) nitride, Cu 3 N and its multinary derivatives containing either main group or transition metal elements. For many years, research in this area was focused on the development of copper nitride prepared in the form of thin films. Successful deposition of these materials has been achieved mainly by employing physical methods, which have provided materials suitable for potential application in optical data storage. However, for the last decade, attention has also been devoted to expanding the available options by which Cu 3 N can be synthesized and deposited. Consequently, the focus has switched to the development of chemical synthetic methods towards the fabrication of this semiconductor and to broadening the range of related compounds that might be discovered. Simultaneously, the formulation of novel techniques and the successful preparation of new nanostructured functional materials has resulted in the rapid evolution of new and relevant applications; e.g. catalytic and electrochemical. The overview presented here concentrates on the chemical methods that have been devised to synthesise both bulk samples and thin films of Cu 3 N. Our article also shows how these approaches have been developed to achieve significant progress in the creation of multinary copper based nitrides and in identifying their potential applications. It provides a concise history of previous copper nitride research and sets the context for the most current advances. These will no doubt provide the springboard for future research areas that will impact both transition metal nitride chemistry and materials science more generally.

Metal Pollutions and Human Health Risks in Groundwater from Wet, Normal, and Dry Periods in the Huixian Karst Wetland, China

The concentrations of 10 metals (Cd, Cr, As, Al, Cu, Pb, Zn, Mn, Hg, and Fe) in 27 groundwater samples collected during different periods (wet, normal, and dry) in the Huixian Karst wetland, the largest subtropical low-altitude karst wetland in China, were detected and analyzed to investigate pollution and health risks. The pollution characteristics, distribution, and health risks of the metals in groundwater were revealed by a comprehensive pollution assessment, multivariate statistical analysis, and health risk assessment model, respectively. The results showed that the average concentrations of metals in groundwater were followed the order of Mn > Fe > Zn > Al > Hg > Cr > Cu > Cd > As > Pb. The maximum concentration of Mn (1022.00 μg·L-1) was found in the wet season, while that of Hg (42.40 μg·L-1) was found in the normal season, and both were over the corresponding standard limits. The results of the pollution assessment indicated that only Mn pollution reached level Ⅵ in the wet season, while Cd, Al, Zn, and Fe pollution were at the level of Ⅲ. Only the Hg pollution level reached level Ⅵ while Al pollution reached the level of Ⅲ in the normal water period. According to the above results, the water quality in the dry season was better than that in the wet and normal seasons in terms of the 10 metals. The concentrations of Zn, Cd, Mn, and Al in groundwater were affected by human activities, while the time-scale characteristics of these were not obvious. The concentrations of As, Fe, Cu, and Cr were all affected by human activities and the time-scale, while the concentrations of Hg and Pb were mainly manifested in time-scale characteristics. The results of the health risk assessment of the water due to drinking and the skin penetration pathway indicated that the total health risks followed the order of normal season > the wet season > the dry season. The carcinogenic risks caused by Cr for adults and children through drinking pathway in the wet season (8.03×10-5 a-1 and 8.76×10-5 a-1), normal season (1.15×10-4 a-1 and 1.26×10-4 a-1),and dry season (8.72×10-5 a-1 and 9.51×10-5 a-1) exceeded the maximum allowed level (5.0×10-5 a-1) in all periods. Hence, Cr was the main metal element that caused carcinogenic risks. For the sake of drinking water safety, the concentrations of Mn, Hg, and Cr in groundwater should be controlled before drinking.

Catalysis using transition metal complexes featuring main group metal and metalloid compounds as supporting ligands.

Recent development in catalytic application of transition metal complexes having an M–E bond (E = main group metal or metalloid element), which is stabilized by a multidentate ligand, is summarized. Main group metal and metalloid supporting ligands furnish unusual electronic and steric environments and molecular functions to transition metals, which are not easily available with standard organic supporting ligands such as phosphines and amines. These characteristics often realize remarkable catalytic activity, unique product selectivity, and new molecular transformations. This perspective demonstrates the promising utility of main group metal and metalloid compounds as a new class of supporting ligands for transition metal catalysts in synthetic chemistry.

Transmetalation: a fundamental organometallic reaction critical to synthesis and catalysis

A number of critical reactions form the foundation of organometallic chemistry. One such fundamental reaction of organometallic chemistry is transmetalation, a general term that in its modern meaning describes the transfer of carbon ligands (i.e., alkyl, aryl, alkynyl, allyl, etc.) from one metal to another. Transmetalation has a very long history and the reaction dates back to the early beginnings of organometallic chemistry with the work of the English chemist Edward Frankland (1825–1899) in the 1860s. Since its introduction, transmetalation has found significant utility in synthetic chemistry, allowing the generation of a wide variety of organometallic compounds of both main group and transition metal elements, and has been identified as a critical step in many synthetic organic reactions catalyzed by transition metal complexes. Regardless of the long history of this reaction and its significant applications, transmetalation is not covered in the same depth as other fundamental reactions in organometallic chemistry and is rarely given serious treatment in organometallic textbooks. Thus, the aim of the current work is to supplement current textbooks by presenting the basics of what is currently known about the details and parameters of this important reaction.

Metal Distributions and Human Health Risk Assessments on Waters in the Huixian Karst Wetland, China

The concentrations of nine metals (As, Cr, Al, Cu, Pb, Zn, Ni, Mn, and Hg), in 23 water samples collected from four main types of water (well, surface river, subterranean stream and blue hole), in the Huixian karst wetland were determined and analyzed to investigate their distributions and health risks. A multivariate statistical analysis was used to study the distribution characteristics of the metals. A human health risk assessment model was developed to assess the health risks. The results found that the mean concentrations of metals in water from the Huixian karst wetland were in the order:Al > Mn > Zn > Cr > Ni > As > Hg > Cu > Pb. The maximum concentrations of Hg (1.08 μg·L-1) in the well water, Hg (0.78 μg·L-1) and Mn (259.00 μg·L-1) in the surface river water, and Hg (0.47 μg·L-1) and Al (300.00 μg·L-1) in the blue hole water all exceeded the corresponding standard limits. The metal concentrations in the subterranean stream samples were all within the regulated limits. For the nine metals, the well water and the subterranean stream water qualities were better than those of the surface river and the blue hole. The results of the multivariate statistical analysis showed that the concentrations of Cr, Ni, Cu, and Zn in the well water were mainly related to the regional geological background, while the concentrations of Al and Pb in the blue hole water were mainly affected by pyrite mining and residential activities. The concentrations of As and Mn in rivers may be affected by tourism activity, aquaculture and river sediments. The results of the health risk assessment on water through the drinking and skin penetration pathway indicated that the total health risks order was:well > subterranean stream > blue hole > surface river. The total health risks values of well water as drinking water for adults (6.11×10-5 a-1) and children (6.67×10-5 a-1) exceeded the maximum allowance level (5.0×10-5 a-1). Cr was the main metal element that causes carcinogenic risks. For drinking water safety, the concentrations of Hg and Cr in well water should be controlled before drinking.

Experimental study on the separation of a shrend copper slag

An experimental study on copper separation from a shrend copper slag in Yunnan province was carried out. The test contents included: grinding curve test, grinding process determination test, comparison tests of different flotation processes. The results shown that: the main ingredients of shrend copper slag were iron, silicon and the main valuable metallic elements were Cu, Fe, grade of 0.70%, 40.14%, consistent with the main components of the copper smelting slag. When the grinding time exceeded 35 minutes, the grinding fineness curve tended to flatten, indicating that the grinding effect was not obvious after the time exceeded 35 minutes, and the grinding fineness did not change much, which may be the shrend copper slag crystallized into a dense structure during the cooling process. Finally, the two stages grinding and regrinding process was adopted. Under the fineness of -0.074 mm 70% on the first grinding, the fineness of -0.037 mm 100% on the second grinding, and the fineness of -0.026 mm 85% on the regrinding, the process of regrinding and recleaning for combined cleaning middling of sulfide copper with roughing and scavenging middling of oxidized copper was suitable for the shrend copper slag.

Source apportionment of metallic elements in urban atmospheric particulate matter and assessment of its water-soluble fraction toxicity.

Clean air is essential for the maintenance of human life and environmental balance. The atmospheric particulate matter (PM) is one of the main air pollutants and is characterized by the heterogeneity of its composition, being able to accumulate numerous components, such as metallic elements, which contribute to increasing its toxicity. The objectives of this study were to assess of the air quality in two urban environments, to carry out the source apportionment of the metallic elements Al, Ba, Cd, Pb, Cu, Cr, Fe, Mn, Ni, and Zn in the PM2.5 and PM2.5-10, and evaluate the toxicity of PM2.5 and PM2.5-10 water-soluble fractions using Lactuca sativa as bioindicator. The collection of PM2.5 and PM2.5-10 was performed using a dichotomous stacked filter unit (SFU) sampler. The source apportionment was carried out using the EPA PMF 5.0 receptor model and the toxicity tests followed the EPA Ecological Effects Test Guidelines OPPTS 850.4200: Seed Germination/Root Elongation Toxicity Test. The source apportionment demonstrated that vehicular and industrial emissions are the main anthropogenic sources contributing to the concentration of metallic elements to thePM2.5 and PM2.5-10. The studied sites did not show statistically significant differences in terms of phytotoxicity to the Lactuca sativa seeds. Cd and Cu were identified as the main metallic elements which able to cause negative effects on seed germination and root elongation, respectively. The presence of cadmium and copper in the atmospheric particulate matter is one of the main causes of the phytotoxicity affecting the Lactuca sativa seed germination and root elongation.

Electrochemical recovery of cobalt using nanoparticles film of copper hexacyanoferrates from aqueous solution

Nanoparticles film of copper metal hexacyanoferrates (CuHCF) was fabricated to electrochemically separate Co2+ in aqueous solutions under various conditions such as applied potential, solution pHs, initial concentrations, contact time and coexisting ions. Results showed that the removal efficiency conducted in reduction potential was obviously higher than that in oxidation potential. The optimal pH for Co2+ adsorption occurred at 8.0. Coexisting ions studies revealed that Co2+ could be removed from aqueous solutions containing Li+, Cu2+ and Al3+. Considering that cobalt and lithium are the main metallic elements in LiCoO2, the effect of different ionic strengths (IS) of LiNO3 (0.5, 1, 2, 5, 10) on adsorption was further investigated. Results showed that IS of LiNO3 had little impact on the removal efficiency of Co2+, which indicated the potential of selective recovery of cobalt from LiCoO2 in spent lithium-ion batteries. X-ray energy-dispersion spectroscopy (EDS) confirmed that the Co2+ could be adsorbed effectively onto CuHCF film. The adsorption was well described by Langmuir isotherm and the maximum sorption capacity is 218.82 mg/g. The kinetic rate of Co2+ adsorption was rapid initially and attained equilibrium within 60 min, and the data well fitted the Redlich-Peterson and the Elovich model, implying a chemisorption dominated process.

Investigation on Heavy Metal Pollution Risk of Sediment in a Human-disturbed River, China

Analysis of heavy metal pollution in sediment is of importance to water treatment. In the present study, borehole columnar sediment samples with 3~4 m thickness from 86 points along Maozhou River were collected to determine the concentrations of six main metal elements (Cu, Cr, Cd, Pb, Zn, Ni) using plasma direct reading spectroscopy. Then, the vertical distribution of heavy metal among sediment is revealed. What’s more, the pollution risk levels at different depths are determined by potential ecological risk index. The heavy metal source is also discussed through correlation analysis between different heavy metal elements. The result of this study provide valuable reference for dredging depth determination as well as treatment of malodorous black water body.

Occurrence, speciation, and risks of trace metals in soils of greenhouse vegetable production from the vicinity of industrial areas in the Yangtze River Delta, China.

The effect of industrial activities on trace metals in farmland of rapidly industrializing regions in developing countries has increasingly been a concern to the public. Here, soils were collected from 13 greenhouse vegetable production (GVP) farms or bases near industrial areas in the Yangtze River Delta of China to investigate the occurrence, speciation, and risks of Cr, Cu, Zn, Cd, Ni, and Pb in GVP soil. The results revealed that the main metal elements causing GVP soil pollution were Cd, Zn, Ni, and Cu, of which contamination levels were generally unpolluted to moderately polluted. Zinc pollution was mainly attributed to heavy fertilization, while Cd, Ni, and Cu pollution may be greatly ascribed to industrial effluents and coal combustion. Metal speciation studies showed that most of Cr, Ni, Cu, and Zn was present in residual fraction while more than half of Cd and Pb was present in non-residual fractions. Additionally, pollution of Cd, Cu, Ni, and Zn in GVP soil increased their corresponding mobile fractions. Risk assessment using potential ecological risk index and risk assessment code showed that Cd was the major risk contributor. Specifically, Cd generally posed moderate or considerable ecological risk as well as displayed medium or high mobility risk in GVP soil. Thus, great attention should be paid to the contribution of both industrial discharges and intensive farming to soil pollution by trace metals, especially Cd, because of its high mobility risk.

Distribution of minor metallic elements within waste incineration bottom ashes defined by WDX/EDX spectrometry

Abstract. A number of metallic elements are inherited from waste during thermal treatment and concentrated in the incineration residues. Because the major part of the incineration residue mass are bottom ashes (BAs), their study is of great importance from the point of view of their environmental impact or resource potential. The general focus of this study was on the minor metallic elements present in BAs. They co-occurred with main phases and often determined the inherited potential of the material. The analysed residues were produced from municipal and industrial waste. The BAs were studied using spectroscopic methods of chemical microanalysis: energy dispersive X-ray spectrometry (EDX) and wavelength dispersive X-ray spectrometry (WDX). Both the main and minor metallic elements were concentrated in metallic components. They were typically present as separate grains and metallic inclusions (commonly in the glass matrix of the grains) ranging in size from several to hundreds of micrometres. Despite Fe-, Al- and Cu-rich occurrences, metallic elements rarely occurred in fragments composed of a single element. Their main forms of occurrence were alloy grains, admixtures in polymetallic occurrences and micro-inclusions in glassy matrix. The content of particular elements in those forms was investigated and described in greater detail. Even though two types of bottom ash were formed from different types of waste and differences in used technologies were present, the obtained materials contained metallic components having similar attributes. Elevated concentrations of not only Fe and Al, but also Ti, Cu and Zn, allow us to consider bottom ash as a promising material from the point of view of metallic elements' recovery (e.g. by the physical concentration of elements through gravity or magnetic methods).

The Cluster Valence Electrons (VE) Are Natural Numbers of Clusters Generated by K(N) Parameters: VE and K(N) Are Intertwined

The paper presents a highly refined work on broad categorization of clusters using the series method with emphasis on cluster valence content. In this regard, the K(n) parameter plays a crucial role. The K(n) parameters are interrelated and have been utilized to generate a cluster map of clusters. The cluster map of skeletal elements and their clusters can be extended indefinitely. The elements refer to main group and transition metal elements. The inter-conversion of K(n) parameter map into a selected portion of cluster valence electron content map was done indicating the origin of the cluster valence electron numbers which are sometimes associated with certain characteristic geometries. The map indicates that the main group and transition metal elements and their clusters are all interlinked via either the K(n) map or the cluster valence electron content map.

Cooperative Decomposition of Hydrogen Peroxide by Lignin-combined Transition Metals in Pulp Bleaching

The effects of lignin-combined manganese ion, iron ion, and lignin-combined iron and manganese on the decomposition of hydrogen peroxide were investigated. Elemental analysis and inductively coupled plasma-atomic emission spectrometry were used to analyze the chemical features of the lignin composites and the amount of metal ions present in the solution or adsorbed on lignin, respectively. The results showed that the main transition metal elements remaining in the precipitated lignin were Fe, Mn, and Cu. The hydrogen peroxide decomposition in the presence of lignin-combined transition metal was represented by pseudo-first-order kinetics, and the pseudo-first-order rate constant (kobs) of peroxide decomposition with lignin-combined iron was 0.0068 min-1, while it was 0.0063 min-1 in the presence of lignin-combined manganese. A synergistic effect of manganese and iron combined with lignin on peroxide decomposition was demonstrated, and a kobs value of 0.0053 min-1 was obtained. The mixed addition of magnesium sulfate (MgSO4), sodium silicate (Na2SiO3), and ethylene diamine tetraacetic acid disodium salt (Na2EDTA) resulted in an optimal reduction in peroxide decomposition when single lignin-combined metal ion existed. However, adding Na2EDTA alone had an optimal effect on the reduction of peroxide decomposition in the presence of lignin-combined iron and manganese, with a kobs value of 0.0004 min-1.