Initial Manganese Concentration Research Articles

Global pattern and drivers of stable residue size from decomposing leaf litter

Stable residue from decomposing leaf litter is related to humus buildup in the forest floor and thus to the accumulation of carbon in the soil organic layer (OLC). However, the global pattern and controls of stable residue size remains poorly understood. Herein, the spatial pattern of stable residue size and its association with a series of potential drivers were evaluated by synthesizing available data worldwide. The results showed that stable residue size had a significant and positive correlation with the litter initial nitrogen (N) and lignin concentrations, and a negative correlation with the initial manganese concentration. Larger stable residues were found from decomposing broadleaf litter vs. coniferous litter. The decomposition of green leaf litter produces an equal amount of stable residue as that of brown litter. Stable residue size correlated quadratically with mean annual temperature and latitude, and linearly with mean annual precipitation. Methodological factor also matters, because stable residue size decreased as field incubation time increased. The boosted regression tree model indicated that litter initial traits have the most explanative ability for the variance in stable residue size. We highlighted that litter initial traits exert a predominant role over climate in shaping the stable residue size globally. Our findings are beneficial for a more accurate prediction of global-scale OLC accumulation.

Chemical Treatment of Banana Blossom Peels Adsorbent as New Approach for Manganese Removal: Isotherm and Kinetic Studies

This research aimed to investigate the potential of chemically modified banana blossom peels (BBP) as an adsorbent for removing manganese (Mn) from water. Zeta potential, field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer–Emmet–Teller (BET) were used to characterise the BBP adsorbent. Batch adsorption studies were used to assess the effects of the solution pH, adsorbent dosage, initial manganese concentration, and contact time of the adsorption process. Zeta potential of BBP with a value of −9.87 to −21.1 mV and FESEM analysis revealed deeper dents and rough internal surfaces conducive to Mn deposition, whereas EDX analysis revealed the presence of C, O, and Na elements (before adsorption); C, O, and Mn (after adsorption). The presence of hydroxyl, carboxylic, and amino groups, which are responsible for the adsorption process, was discovered using FTIR analysis. Furthermore, XRD analysis revealed that the BBP adsorbent structure is amorphous. The BBP adsorbent has a BET surface area of 2.12 m2/g, a total pore volume of 0.0139 cm3/g, and an average pore diameter of 64.35 nm. The BBP adsorbent demonstrated remarkable results of 98% Mn removal under the optimum pH 7, 0.5 g (adsorbent dosage), and 10 mg/L of Mn initial concentration in 150 min of contact time. The linear Langmuir and Freundlich isotherm models best fit the adsorption isotherm data with the R2 > 0.98. In contrast, the adsorption process occurs as a function of the chemisorption as determined by linear pseudo-second-order kinetics. Using 0.1 M HCI, the maximal desorption rate of Mn was 92% in the first cycle, with a recovery rate of 94.18% Mn removal in 30 min. These findings support the use of BBP as a natural adsorbent for Mn removal as a treatment option for improving wastewater quality.

Initial stage of innovative cell-entrapped biofilter start-up for removal of manganese in water: Treatment performance, manganese speciation, and microbial community

Manganese-contaminated groundwater as a drinking water source causes colored water, pipe clogging, and health problems. Manganese removal using biofilters is an effective process, but microbial acclimatization during the start-up period takes time. The aim of this study is to investigate the initial stage of an innovative cell-entrapped biofilter start-up for manganese removal. Streptomyces violarus SBP1 (SBP1) entrapped in barium alginate was incorporated into the biofilter to enhance manganese removal and cell retention. The manganese removal performance, microbial community, and manganese transformation were examined through dual media columns representing free cell-augmented (FC), entrapped cell-augmented (EC), and conventional biofilters at an initial manganese concentration of 1 mg/L. In a filtration experiment, EC achieved better removal performance (53 %) than FC (45 %) and conventional biofilter (39 %) because of higher manganese bio-oxidation. During the beginning period, manganese adsorption was predominant, whereas manganese bio-oxidation played a main role thereafter. A synchrotron-based analysis confirmed that most Mn(II) was oxidized to Mn(III) and Mn(IV). The amplicon sequencing results revealed that Proteobacteria-dominated natural biofilm in all three filters, while Streptomyces (expected as SBP1) was the major bacterial group in EC. This study demonstrated the feasibility of developing an innovative cell-entrapped biofilter.

Removal of manganese from aqueous solution by a permeable reactive barrier loaded with hydroxyapatite-coated quartz sand.

Hydroxyapatite-coated quartz sands were synthesized by the sol-gel method and employed as a permeable reactive barrier (PRB) medium for the manganese contaminated aqueous solution treatment. The effects of composite particle size, initial concentration of manganese, and hydraulic load on the manganese removal in aqueous solution were investigated by column test. The Thomas and Yoon-Nelson dynamic models were used to reproduce the Mn(II) adsorption behavior observed in these column experiments. The scanning electron microscope (SEM) coupled with energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) were employed to investigate the Mn(II) removal mechanism. Results showed that the initial concentration of manganese had the greatest influence on Mn(II) removal when the initial concentration of manganese is 3mg/L, the particle size is 0.15 ~ 0.3mm, the hydraulic load is 5.5 m3/m2·d, and the adsorption capacity of the composites reached the maximum of 1.10mg/g. The Thomas model fitted the breakthrough curves better. The maximum adsorption capacity of Mn(II) is 0.7546mg/g. The adsorption mechanisms are mainly ion exchange and dissolution-precipitation. The results indicate that the hydroxyapatite-coated quartz sands could be an effective PRB media for the manganese-contaminated water treatment.

ДОСЛІДЖЕННЯ ПРОЦЕСІВ ОЧИЩЕННЯ ВОДИ ВІД ІОНІВ МАНГАНУ ПРИ ВИКОРИСТАННІ РОЗЧИНІВ НАТРІЙ ГІПОХЛОРИТУ

The creation of effective demanganization technologies by the development of new and intensification of known processes of manganese removal from natural waters are currently of increasing importance.The search for promising ways to demanganize water to regulatory values is a topical issue for the modern water treatment domain.Recent publications of methods for extraction of manganese ions from water by sorption, membrane, ion exchange methods were reviewed. The prospects of application of oxidative methods for water demanganation are shown.The purpose of the article is to investigate the manganese ions removal methods from water during their oxidation by sodium hypochlorite and to establish the dependence of the efficiency of demanganization on the consumption of oxidizing agent and the concentration of manganese ions in water.The study presents the application of sodium hypochlorite as an oxidant in the purification of artesian water from manganese ions. It was determined in static conditions that the degree of manganese removal is affected by both its initial concentration in water and the dose of sodium hypochlorite. Water purification process is more efficient with initial manganese concentrations above 5 mg/dm3. At a manganese ion concentration 30 mg/dm3, its complete removal was achieved in 4 hours of settling at a stoichiometric ratio of manganese and sodium hypochlorite in water and at any excess of oxidant. The process of manganese ions oxidation in artesian water by sodium hypochlorite depending on its dose and contact time was studied. The dose of oxidant for the removal of manganese ions from artesian water was also determined. Thus, the research allowed to improve the methods of water purification from manganese ions during their oxidation by sodium hypochlorite and found that the water purification efficiency increased both with increasing consumption of oxidizing agent and increasing the concentration of manganese ions in water.

Manganese Deposition Content in Carbon Nanotubes Based Filters: Energy Dispersive X-ray and Rutherford Backscatter Spectrometry Investigations

Carbon nanotubes (CNTs) based filters have a prospective advantage compared to the commercial filters due to their lightweight and ability to work without electricity or heat. The manganese (Mn) removal from aqueous solutions by oxidized multi-walled carbon nanotubes (O-MWCNTs) was investigated. The filtration performance was studied under ambient conditions: the solution pH, the initial manganese concentration, and the MWCNT-filter mass. The samples of MWCNT-filters were investigated using energy dispersive X-ray spectroscopy (EDS) and rutherford backscatter spectrometry (RBS) to account for the manganese content within the MWCNT-filter. These techniques were conducted to study the oxidation effect on the morphology of MWCNTs and evaluate the oxygen functional groups and the average diameter distribution. Based on these examinations, the competence of Mn removal may exceed 91% for 50 ppm initial concentration of Mn, proposing that functionalized MWCNTs is a promising filter. The Mn removal was achieved at low pH with removal enhancement at the pH of 2. Functionalized MWCNTs based filters are promising candidate for heavy metal ions removal from industrial wastewater.

Simultaneous adsorption of manganese and fluoride from aqueous solution via bimetal impregnated activated carbon derived from waste tire: Response surface method modeling approach

AbstractAdsorptive removal of manganese and fluoride from wastewater by waste tire‐derived activated carbon impregnated with iron and cobalt has been presented in this article. The surface properties of bimetallic activated carbon were characterized in scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and X‐ray diffraction (XRD). The newly developed adsorbent was used for simultaneous removal of fluoride and manganese from aqueous solution. Present work focuses on the optimization of process parameters using response surface method (RSM) technique employing significant parameters, namely, adsorbent dosage, initial fluoride and manganese concentrations, contact time and pH. Central composite design in RSM was utilized for the levels of adsorbent dosage (0.5–1 g/L), initial fluoride concentration (20–40 ppm), initial manganese concentration (30–50 ppm), time (15–35 min), and pH (4–8) of the solution. The R2 value obtained from the statistics data was 96.25 and 97.57% for fluoride and manganese, respectively. The optimal values were determined as the adsorbent dosage of 1.25 g/L, initial fluoride concentration of 10 ppm, initial manganese concentration of 25.25 ppm, the contact time of 30.9 min and pH of solution of 2.0, under which 99.96% manganese and 85.34% fluoride removal efficiency could be accomplished.

Purification of Water from Manganese Compounds on a Modified Ceramic Membrane of Clay Minerals

A high efficiency of the process of water purification from Mn(II) compounds formed at pH 8.3–8.4 on a Mn(II) modified microfiltration tubular ceramic membrane of clay materials, which was developed in the Dumansky Institute of Colloid Chemistry and Water Chemistry of the National Academy of Sciences of Ukraine, was shown. The conditions for the dynamic modification of the ceramic membrane with these compounds were determined. The effect of the initial Mn(II) concentration in a solution and its pH, the working pressure, the water purification time, and the additives of salts containing Cl–, $${\text{SO}}_{4}^{{2 - }}$$, $${\text{HCO}}_{3}^{ - }$$, and Са2+ions on the separation properties of the modified ceramic membrane was studied. The purification of water from Mn(II) compounds on the ceramic membrane was studied on the model MnCl2 ⋅ 4H2O salt solutions within a concentration range of 1.5–33.0 mg/dm3. It has been established that such a membrane can purify water from Mn(II) compounds to their maximum permissible concentration in drinking water at an initial manganese concentration of up to 4.34 mg/dm3, pHinit = 8.4, a working pressure of 1.0 MPa, and a purification time of 75–100 min, when a solution contains Cl–, $${\text{HCO}}_{3}^{ - }$$, $${\text{SO}}_{4}^{{2 - }}$$, and Ca2+ions, respectively, at a concentration of 200 mg/dm3 for each of the ions. The addition of salts containing the above ions to the initial solution at the moment when the maximum permissible concentration of manganese was attained had a slight effect on the ability of this ceramic membrane to retain the Mn(II) compounds. In this case, the specific productivity of the membrane was ranged within 0.16–0.20 m3/(m2 h). The obtained results might be explained by the steric membrane action mechanism based on the difference between the sizes of Mn(II) compound particles and membrane pores themselves with the further formation of an additional modifying layer of these particles on its surface.

Manganese Removal from Liquid Nickel by Hydrogen Plasma Arc Melting.

In this work, the removal of manganese from nickel melts by Ar and (10%, 20% and 40%) H2 plasma arc melting under various pressures (0.01–0.02, 0.04–0.05 and 0.09–0.1 MPa) was investigated experimentally. The results show that only a slight reduction in the manganese content is obtained by Ar plasma arc melting (PAM). By contrast, the manganese content of liquid nickel decreases noticeably upon the addition of hydrogen to plasma gas, and the rate of manganese removal increases with increasing hydrogen volume fraction. In addition, the reduction in the pressure enhances the efficiency of manganese removal from liquid nickel by hydrogen plasma arc melting (HPAM). The process of manganese removal by HPAM was found to obey a first-order rate law. From kinetic analysis, the rate of reduction in the manganese content increases proportionally to the 0.73–0.75th power of the hydrogen volume fraction in the plasma gas. However, the rate of the manganese content reduction increases proportionally to approximately 0.88th power of %H2 in the plasma gas for the initial manganese content of 0.89 mass%, which is slightly higher than that for the initial manganese concentration of 0.45 mass%. Thermodynamic analysis indicates that the volatilization of manganese benefits from negative pressure and the presence of active hydrogen atoms that act as the transfer media of the metal vapor in the gas boundary layer.

Application of a novel phyco-composite biosorbent for the biotreatment of aqueous medium polluted with manganese ions

ABSTRACTA composite phyco-biomass including four different marine macroalgae species (Chaetomorpha sp., Polysiphonia sp., Ulva sp., and Cystoseira sp.) was evaluated as a novel biosorbent for the biosorption of manganese ions from aqueous solution. The experimental studies were performed to optimize the operational factors including solution pH, biosorbent amount, initial manganese concentration, and reaction time in a batch-mode biosorption system. The removal yield of the biosorbent for manganese ions increased with increasing pH, manganese ion concentration, and reaction time, while it decreased as the biosorbent dose increased. The obtained kinetic data indicated that the removal of manganese ions by the biosorbent was best described by the pseudo-second-order model and the pore diffusion also contributed to the biosorption process. The results of isotherm and thermodynamic studies showed that the Freundlich model represented the biosorption equilibrium data well and this biotreatment system was feasible, spontaneous, and physical. The maximum manganese uptake capacity of used biosorbent was found to be 55.874 mg g−1. Finally, a single-stage batch manganese biosorption system was designed and its kinetic performance was evaluated. All these findings revealed that the prepared composite macroalgae biosorbent has a fairly good potential for the removal of manganese ions from the aqueous medium.

Enhancement of CNT-based filters efficiency by ion beam irradiation

It is shown in the report that disorder produced by ion beam irradiation can enhance the functionality of the carbon nanotubes. The filters of pressed multiwalled carbon nanotubes (MWNTs) were irradiated by He+ ions of the energy E = 80keV with the fluence 2 × 1016ion/cm2. The removal of manganese from aqueous solutions by using pristine and ion beam irradiated MWNTs filters was studied as a function of pH, initial concentration of manganese in aqueous solution, MWNT mass and contact time. The filters before and after filtration were characterized by Raman (RS) and energy dispersive X-ray spectroscopy (EDS) techniques to investigate the deposition content in the filter and defect formation in the MWNTs. The irradiated samples showed an enhancement of removal efficiency of manganese up to 97.5% for 10ppm Mn concentration, suggesting that irradiated MWNT filter is a better Mn adsorbent from aqueous solutions than the pristine one. Radiation-induced chemical functionalization of MWNTs due to ion beam irradiation, suggesting that complexation between the irradiated MWNTs and manganese ions is another mechanism. This conclusion is supported by EDS and RS and is correlated with a larger disorder in the irradiated samples as follows from RS. The study demonstrates that ion beam irradiation is a promising tool to enhance the filtration efficiency of MWNT filters.

Removal of Iron and Manganese from Aqueous Solution Using Hydroxyapatite Prepared from Cow Bone

Functionalized hydroxyapatite was synthesized from cow bone as model adsorbent for the removal of manganese and iron which often occurs as geogenic contaminants in untreated surface and ground water. The adsorption behaviour was studied by batch method. Prepared adsorbent was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and X-ray Fluorescence. The effect of initial concentration, pH value of aqueous solution, contact time, adsorbent dose and temperature were the parameters used in determining the optimum conditions of the adsorption process. 60 minutes was established to be the adsorption equilibrium time and the equilibrium adsorption experimental data for the metals were establish to suit the Langmuir adsorption isotherms best and the maximum adsorption capacity was 14.68 mg/g and 2.54 mg/g for Mn and Fe respectively. The adsorption kinetics for the adsorbates was defined best by the pseudo second order kinetic model. The adsorption process is endothermic as revealed by the thermodynamic experiment and the reaction is spontaneous as shown from the values of the free energy change. The hydroxyapatite (adsorbent) was applied to typical raw water with 1.52 mg/l and 3.89 mg/l as the initial concentration of manganese and iron respectively and the removal efficiency for Mn and Fe was 91% and 48% respectively. The results shows that the functionalized hydroxyapatite has great prospective for wastewater and water treatment.

Manganese Removal from Aqueous Solution by Ozonation Process Designed by Box-Behken Design (BBD)

The aim of this research was to investigate interactions in the removal of manganese from contaminated water by oxidation through an ozonation process. The manganese oxidation was used to oxidize manganese ions (Mn2+) in solution to manganese dioxide (MnO2) in its brown solid form, in order to reduce levels of manganese ions in the water to below the acceptable limit for drinking water (0.05 mg L-1). In this study, the independent effects such as the initial concentration of manganese (5, 10 and 15 mg L-1), initial pH of solutions (3, 4 and 5) and ozone concentrations (10.970, 21.945 and 32.920 mg L-1) designed Box-Behnken Design (BBD) as a one of the design of experiments were examined foroptimal conditions and including main effects and their interactions. The ozone concentration in the reactor was increased with increasing operating time of an ozone generator and linearly increased at the rate about 2.194 mg O3 L-1 min-1. The experimental results indicated that all factors significantly affected manganese removal rate. Initial manganese concentration was negatively correlated, while pH and ozone concentration were both positively correlated with removal percentage. Main, square and interaction effects were significant on percent manganese removal. Additionally, percent removal was reduced with increasing ozone concentrations because at higher ozone levels, MnO2 in solid form was converted to MnO4- and re-dissolved into solution- a process known as over-oxidation. The maximal condition, the removal efficiency of manganese in oxidation reaction by ozonation process in initial manganese concentration 5 mg L-1, pH 4.0 and ozone concentration 21.945 mg L-1 was appeared more than 100 %. The present study indicates that manganese ions can be effectively removed from drinking water by ozonation.

Part I: the influence of serial repitching ofSaccharomyces pastorianuson the uptake dynamics of metal ions and fermentable carbohydrates during the fermentation of barley and gluten-free buckwheat and quinoa wort

Recently, research has been focusing on the use of alternative raw materials for brewing purposes and gluten-free beer-like beverages from malted buckwheat and quinoa are of commercial interest. A common commercial process involves the serial repitching of the yeast biomass, but this has not been described using buckwheat and quinoa wort fermentations. Our research studies (Parts I–III) explored the serial repitching of the yeast strain Saccharomyces pastorianus TUM 34/70 on the composition of a barley, buckwheat and quinoa fermentation medium. The present paper focuses on the fermentation performance and the uptake dynamics of metal ions and fermentable carbohydrates. Both pseudocereals showed high variations in all of the attributes examined during successive fermentations. In buckwheat the differences between successive fermentations were similar to those observed with barley, whereas differences in quinoa varied quite significantly from those observed with barley and showed a directional trend, suggesting a general weakening of the yeast from the sixth successive fermentation onward. In particular, the assimilation of the fermentable carbohydrates lessened and metal ion uptake appeared poorly controlled. It was concluded that buckwheat showed good potential for serial repitching of S. pastorianus TUM 34/70, whereas serial repitching of a quinoa wort appeared to be limited to five or six fermentations. Copyright © 2015 The Institute of Brewing & Distilling

Removal of Mn(II) compounds from water in electrodialysis desalination

The article has studied the influence of the nature of background electrolyte on kinetics of removal of Mn(II) ions from model solutions in the course of electrodialysis desalination. The possibility of deep removal of manganese from different types of waters until MAC for drinking water (0.05 mg/dm3) at the initial concentration of manganese 3–5 mg/dm3 has been shown. It has been proposed the use of additives of antiscalant ACUMER 2200 in chambers of concentration of electrodialysis unit for preventing deposition of barely soluble manganese compounds on the giving up surface of anon exchange membranes under conditions of strict concentration polarization.

Adsorption of Manganese in Aqueous Solution by Steel Slag

Batch experiments had been conducted to evaluate the ability of steel slag in removing manganese from aqueous solution. Several variables had been setup to evaluate the performance of steel slag in different experimental conditions. The variables include contact time, dosage, pH and initial concentration of manganese. The equilibrium contact time was achieved at 10hours. 1g of adsorbent dosage is considered enough to remove heavy metal from aqueous solution. The optimum pH for manganese adsorption onto steel slag was 6. Higher initial concentration leads to the decrease in percentage removal of Mn from solution, but increase in adsorption capacity. The Langmuir isotherm model fits well with data of Mn adsorption onto steel slag compared to Freundlich isotherm model. Steel slag is capable of removing high percentage of Mn from aqueous solution (>95%) in batch experiments, showing potential for real application on-site.

The Effects of an Anionic Membrane on the Electrodeposition of Manganese Ions: A Kinetic and Statistical Study

The kinetic of manganese electrodeposition in sulfated aqueous solutions was examined. The objective of the study was to analyze the effect of the use of an anion exchange membrane, the current density, the pH, the temperature, the addition of selenium dioxide and ammonium sulfate and the initial manganese concentration on the kinetics of manganese electrodeposition. The experimental results agreed well with those of a practical statistical model that can be used to simulate and optimize the electrodeposition process. The results indicate that the use of an anionic membrane (polystyrene substrate and NR4(I) functional group) and the addition of selenium dioxide are absolutely necessary to achieve an efficient process, from the point of view of electricity consumption. It was also found that the optimal pH is between 2.5 and 6.5 and that temperature and mixing did not play a significant role on manganese electrodeposition.

Synthesis of a novel tannin–formaldehyde resin from Acacia nilotica fruit extract and its viability for adsorption of manganese from ground water

A novel tannin–formaldehyde resin was synthesized from Acacia nilotica fruit extract. The experimental factors controlling the resin synthesis were investigated and the obtained resin was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy analyses. The adsorption of manganese as Mn(II) was firstly demonstrated in distilled water solution. The subjected parameters studied for Mn(II) removal by using the resin were the effects of contact time, an initial Mn(II) concentration and the resin dose. The Mn(II) adsorption preceded very fast, and within 3 min the amount of adsorbed Mn(II) for three different initial manganese concentrations (5, 10, and 20 mg/L) approached 60–76% of the maximal uptake potential under the equilibrium conditions. The pseudo second-order equation explained the kinetic data well and the obtained adsorption isotherm data fitted the Langmuir isotherm model which gave high Langmuir capacity (15.54 mg/g) value. The mean adsorption energy (11.04 kJ/mol) computed from the Dubinin–Radushkevich isotherm suggested the ion exchange mechanism for Mn(II) adsorption. Results of the resin application for treatment of natural ground water samples (Bani Mor and El-Fath areas, Assiut, Egypt) showed that reducing the Mn(II) level to minimum and the complete removal depended on the resin dose.

Biokinetics of Thiobacillus thiooxidans for manganese bioleaching

The waste tailing of metals generated during mining processes is degrading the environment by increasing the soil toxicity, leading to disturbances in the ecosystem. This study was initiated to determine the biokinetics of Thiobacillus thiooxidans for manganese bioleaching in the presence of excess sulphur. In batch studies, the effect of manganese concentration on the leaching efficiency of T. thiooxidans was also evaluated, and it was found that as the concentration of manganese increases, the leaching efficiency decreases. This may be due to an inhibitory effect of manganese at higher concentrations. The maximum leaching efficiency of more than 95% was found at lower manganese concentration of 5-25 mg/litre, while the efficiency significantly decreases to 35% at 200 mg/litre manganese. The biokinetic coefficient (maximum growth rate and inhibition constant) was also determined for T. thiooxidans for manganese bioleaching using Haldane's equation. A linear mathematical relationship was also developed between leaching efficiency, initial manganese concentration and time of incubation, which would be useful in predicting the leaching efficiency under various conditions. The significance test using T-paired test was also performed, and it was found that the theoretical leaching efficiency is above 95% confidence level from observed leaching efficiency. The above parameters are invariably required for the design and simulation of batch and continuous bioreactors for bioleaching of manganese tailings. The present work may be useful for management of tailing waste generated during mining processes.

Catalytic ozonation of 2-dichlorophenol by metallic ions

This research is mainly to explore functional improvement by adding various kinds of metallic ions in the ozonation of 2-chlorophenol solution. During the experiment, various kinds of metallic ions (Pb+, Cu2+, Zn2+, Fe2+, Ti2+, and Mn2+) were added; it was found that the reaction rate increased in all cases. The best result was obtained by using manganese ions, followed by iron and titanium ions. At pH = 3 and 1 ppm Mn2+ concentration, the reaction rate was increased by three times. TOC removal rate was also increased from 12.6% to 38% at 60 min reaction time. Ozone self-decomposition with various kinds of metallic ions alone was tested. It was found the ozone self-decomposition coefficient is highly dependent on the reaction rate constant for ozonation of 2-chlorophenol. The improvement of reaction was relevant to the mechanism of reaction between ozone and metallic ions. Furthermore, the effect of adding manganese ions was studied. With the initial manganese concentration at 0-2 ppm, after gas exposure for 20 min the removal rate can be increased from 38% to 93%. TOC removal rate was increased from 11% to 38%. The reaction rate was improved more greatly at the initial pH = 3.