Property and performance of red mud-based catalysts for the complete oxidation of volatile organic compounds

Red mud-based catalysts for the catalytic removal of typical air pollutants: A review

Red mud, as a solid waste produced during the alumina production, can cause severe eco-environmental pollution and health risks to human. Therefore, the resourcing of this type of solid waste is an effective way for the sustainable development. This paper reviews the recent progress on red mud-based catalysts for the removal of typical air pollutants, such as the catalytic reduction of nitrogen oxides (NO_x) by NH₃ (NH₃-SCR) and the catalytic oxidation of CO and volatile organic compounds (VOCs). The factors influencing the catalytic performance and the structure-activity relationship have been discussed. Future prospects and directions for the development of such catalysts are also proposed. This review would benefit for the high value-added utilizations of red mud in mitigating atmospheric pollutions.

Revealing the mechanism of high water resistant and excellent active of CuMn oxide catalyst derived from Bimetal-Organic framework for acetone catalytic oxidation

Environmental H₂O is an influential factor in the low-temperature catalytic oxidation of volatile organic compounds (VOCs), and it significantly impacts the reaction process and mechanism. Here, a series of rod-like Cu-Mn oxides were synthesised by pyrolysing Cu/Mn-BTC for acetone oxidation. The results confirm that the formation of multiphase interfaces have more excellent catalytic performance compared to single-phase catalysis. This phenomenon can be attributed to the formation of multiphase interfaces, which resulted in the synthesized catalysts with more active oxygen species and defective sites. The CuMn₂O_x catalyst exhibited superior catalytic performance (T₉₀ = 150 °C), high water resistance and long-term stability. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy and thermal desorption-gas chromatography-mass spectrometry results indicated that the degradation pathway of acetone was as follows: acetone ((CH₃)₂CO*) → enolate complexes ((CH₂) = C(CH₃) O*) → acetaldehyde ((CH₃CHO*) → acetate (CH₃COO*) → formate (HCOO*) → CO₂ and H₂O. At a low-temperature, water vapour dissociated a large number of activated hydroxyl groups on the multiphase interface, which promoted the dissociation of enolate complexes and acetaldehyde species. This composite oxide is a promising catalyst for removing oxygenated VOCs at high humidity.

Applications of Red Mud as a Masonry Material: A Review

Red mud (RM) is a highly alkaline by-product produced by the aluminium industry. The total stockpile of RM in the world is evaluated to be close 4 billion tons, which caused serious soil and water pollution. The use of RM in masonry materials has proven to be a prospective strategy to alleviate the environmental problems caused by RM. During the past decades, various economical treatment methods have been developed for utilization of RM as a masonry material. There are two general categories of products using RM in masonry materials: sintered products and non-sintered products. In this review, the physicochemical properties of RM are introduced, and the different application scenarios for RM in masonry materials are summarized, which is valuable for solving the environmental problems caused by the accumulation of bauxite residue. Moreover, the potential environmental risks of utilizing RM are described. Finally, suggestions for solving the RM problem are proposed.

Green conversion of hazardous red mud into diagnostic X-ray shielding tiles

Red mud is a solid hazardous alumina industrial waste, which is rich in iron, titanium, aluminum, silicon, calcium, etc. The red mud contains 30-60% of hematite, which is suitable for shielding high energy X- and gamma rays. So, the iron rich red mud was converted into diagnostic X-ray shielding tiles through ceramic route by adding a certain weight percentage of BaSO₄ and binders (kaolin clay or sodium hexametaphosphate) with it. The kaolin clay tile possess sufficient impact strength (failure point is 852 mm for 19 mm steel ball) and flexural strength of ~25 N/mm², which is suitable for wall applications. The 10.3 mm and 14.7 mm thick red mud:BaSO₄:kaolin clay tile possess the attenuation equivalent to 2 mm and 2.3 mm lead at 125 kVp and 140 kVp, respectively. No heavy elements were found to leach out except chromium and arsenic from the sintered tiles. However, the leaching of Cr (0.6 ppm) and As (0.015 ppm) was found to be well below the permissible limit. These tiles can be used in the X-ray diagnosis, CT scanner, bone densitometry, and cath labs instead of toxic lead sheet and thereby to protect the operating personnel, public, and environment from radiation hazards.

Catalytic Ozonation for Effective Degradation of Coal Chemical Biochemical Tail Water by Mn/Ce@RM Catalyst

An Mn/Ce@red mud (RM) catalyst was prepared from RM via a doping–calcination method. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the surface morphology, crystal morphology, and elemental composition of the Mn/Ce@RM catalyst, respectively. In addition, preparation and catalytic ozonation conditions were optimized, and the mechanism of catalytic ozonation was discussed. Lastly, a fuzzy analytic hierarchy process (FAHP) was adopted to evaluate the degradation of coal chemical biochemical tail water. The best preparation conditions for the Mn/Ce@RM catalyst were found to be as follows: (1) active component loading of 3%, (2) Mn/Ce doping ratio of 2:1, (3) calcination temperature of 550 °C, (4) calcination time of 240 min, and (5) fly ash floating bead doping of 10%. The chemical oxygen demand (COD) removal rate was 76.58% under this preparation condition. The characterization results suggested that the pore structure of the optimized Mn/Ce@RM catalyst was significantly improved. Mn and Ce were successfully loaded on the catalyst in the form of MnO2 and CeO2. The best operating conditions in the study were as follows: (1) reaction time of 80 min, (2) initial pH of 9, (3) ozone dosage of 2.0 g/h, (4) catalyst dosage of 62.5 g/L, and (5) COD removal rate of 84.96%. Mechanism analysis results showed that hydroxyl radicals (•OH) played a leading role in degrading organics in the biochemical tail water, and adsorption of RM and direct oxidation of ozone played a secondary role. FAHP was established on the basis of environmental impact, economic benefit, and energy consumption. Comprehensive evaluation by FAHP demonstrated that D3 (with an ozone dosage of 2.0 g/H, a catalyst dosage of 62.5 g/L, initial pH of 9, reaction time of 80 min, and a COD removal rate of 84.96%) was the best operating condition.

Effect of palladium on the black mass-based catalyst prepared from spent Zn/Mn alkaline batteries for catalytic combustion of volatile organic compounds

A large amount of spent batteries is produced annually. When spente batteries are buried, their harmful components may contaminate soil and water. Therefore, recycling of spent batteries is essential for environmental reasons. We evaluated the BM (black mass) of spent Zn/Mn alkaline batteries as a catalyst substance for the catalytic combustion of volatile organic compounds (VOCs: benzene, toluene, and o-xylene). The SBM catalyst (black mass-based catalyst) was prepared by treating BM with 0.1 N of sulfuric acid solution. Major elements of the SBM catalyst were manganese, zinc, iron, aluminum, potassium, and sodium except for carbon. In addition, to find out the additive effect of palladium on the SBM catalyst, we prepared the Pd/SBM catalysts using a conventional impregnation method. We investigated the physicochemical properties of the SBM and Pd/SBM catalysts by instrumental analysis. Benzene, toluene, and o-xylene (BTX) were oxidized completely over the SBM catalyst at reaction temperatures less than 410, 340, and 410 °C, respectively (gas hourly space velocity: 40,000 h^-1). As expected, for the Pd/SBM catalysts, increasing the palladium loading on the SBM from 0.1 wt% to 1.0 wt% increased the conversions of BTX. In the 1.0 wt% Pd/SBM catalyst, the reaction temperatures for catalytic combustion of BTX were greatly reduced to 310, 260, and 250 °C, respectively (gas hourly space velocity: 40,000 h^-1). Instrumental analysis indicated that the increase in activity by adding palladium resulted from the active ingredient (palladium oxide: PdO) and better redox properties.

Performance of platinum doping on spent alkaline battery-based catalyst for complete oxidation of o-xylene

Oxidation of o-xylene was performed using alkaline battery-based catalyst doped with platinum to investigate the properties and activities. O-xylene was selected as the model of volatile organic compound (VOC) in this work. Physicochemical properties of the selected catalysts were characterized by FE/TEM (field emission transmission electron microscopy), BET (Brunauer-Emmett-Teller) analysis, XRD (X-ray powder diffraction), SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectroscopy), and H₂-TPR (hydrogen temperature programmed reduction). Major elements of the spent alkaline battery-based catalyst treated with sulfuric acid solution [SAB (400) catalyst] were manganese, zinc, iron, oxygen, carbon, chlorine, aluminum, sodium, silicon, and potassium. Increasing the doping amount of platinum on SAB (400) catalyst from 0.1 to 1 wt% increased particle size of platinum and lowered the temperature of TPR (TTP) for SAB (400) catalyst. Better redox properties were achieved with an increase in the o-xylene conversion according to the doping amount of platinum. When GHSV (gas hourly space velocity) was 40,000 h^-1, o-xylene was oxidized completely over SAB (400) catalyst and 1.0 wt% Pt/SAB(400) catalyst at temperatures of 400 °C and 280 °C, respectively.

Acid-treated waste red mud as an efficient catalyst for catalytic fast copyrolysis of lignin and polyproylene and ozone-catalytic conversion of toluene

In this study, red mud (RM), a highly alkaline waste generated from alumina production industries, was used as a catalytic material for both fast copyrolysis of organosolv lignin (OL) and polypropylene (PP) and toluene removal under ozone at room temperature. The RM was pretreated with HCl to investigate the effect of alkalinity. In the catalytic fast copyrolysis of the OL and PP, the acid-treated RM (HRM) produced more aromatics, phenolics, and light olefins (C₃ to C₅) but less oxygenates and heavy olefins (C₆ to C₄₆) than the RM. The difference in pyrolytic performance between the RM and HRM was likely attributed to the concentrated Fe₂O₃ species in the HRM catalyst. In addition, more efficient toluene removal was observed over MnO_x/HRM than over MnO_x/RM owing to the large Brunauer-Emmett-Teller surface area, high amounts of Al and Fe, and optimal Mn³⁺/Mn⁴⁺ ratio. This study demonstrates that the RM, an industrial waste, can be reused as an effective catalytic material for not only biofuel production but also pollutant removal.

Cytotoxicity and Potential Pathway to Vascular Smooth Muscle Cells Induced by PM2.5 Emitted from Raw Coal Chunks and Clean Coal Combustion

Coal combustion emits a large amount of PM_2.5 (particulate matters with aerodynamic diameters less than 2.5 μm) and causes adverse damages to the cardiovascular system. In this study, emissions from anthracite and bitumite were examined. Red mud (RM) acts as an additive and is mixed in coal briquettes with a content of 0-10% as a single variable to demonstrate the reduction in the PM_2.5 emissions. Burnt in a regulated combustion chamber, the 10% RM-containing bitumite and anthracite briquettes showed 52.3 and 18.6% reduction in PM_2.5, respectively, compared with their chunk coals. Lower cytotoxicity (in terms of oxidative stresses and inflammation factors) was observed for PM_2.5 emitted from the RM-containing briquettes than those from non-RM briquettes, especially for the bitumite groups. Besides, the results of western blotting illustrated that the inhibition of NF-κB and MAPK was the potential pathway for the reduction of cytokine levels by the RM addition. The regression analyses further demonstrated that the reduction was attributed to the lower emissions of transition metals (i.e., Mn) and PAHs (i.e., acenaphthene). This pilot study provides solid evidence for the cytotoxicity to vascular smooth muscle cells induced by PM_2.5 from coal combustion and potential solutions for reducing the emission of toxic pollutants from human health perspectives.

Getting insight into the effect of CuO on red mud for the selective catalytic reduction of NO by NH3

A series of copper-modified red mud catalysts (CuO/PRM) with different copper oxide contents were synthesized by wet impregnation method and investigated for selective catalytic reduction of NO by NH₃ (NH₃-SCR). The catalytic results demonstrated that the red mud catalyst with 7 wt% CuO content exhibited the excellent catalytic performance as well as resistance to water and sulfur poisoning. The red mud support and copper-containing catalysts were characterized by XRF, XRD, N₂ adsorption-desorption, HRTEM, EDS mapping, XPS, H₂-TPR, NH₃-TPD and in situ DRIFT. The obtained results revealed that well dispersed copper oxide originating from 1 to 7 wt% CuO contents was more facile for the redox equilibrium of Cu²⁺ + Fe²⁺ ↔ Cu⁺ + Fe³⁺ shifting to right to form Cu⁺ and surface oxygen species than crystalline CuO generating from high CuO loading (9 wt% CuO), which was beneficial to the enhancement of reducibility and the formation of Lewis acid sites on the catalyst surface. All these factors made significant contributions to the improvement of NH₃-SCR activities for CuO/PRM catalysts. Moreover, in situ DRIFT analysis combined with DFT calculated results confirmed that the finely dispersed copper species not only enhanced the NH₃ activation but also promoted the NO_x desorption, which synergistically facilitated the NH₃-SCR process via the Eley-Rideal mechanism.

Insights into modified red mud for the selective catalytic reduction of NOx: Activation mechanism of targeted leaching

Red mud (RM) is a solid waste rich in iron oxide, which has the potential to be utilized as the catalyst for selective catalytic reduction (SCR) of NO_x. We pretreated the RM sample with the selective acid leaching method, after which 97.6 % of the alkali was neutralized, and only 8 % of the Fe₂O₃ were leached out. Once leached, the RM samples were activated for the SCR reaction. It showed NO_x conversions above 90 % in 310-430 °C and exhibited high resistance to SO₂ and H₂O. After leaching, i. the S_BET reached twice as before; ii. the sintering caused by alkali was eliminated; iii. the activated RM exhibited improved Fe³⁺/Fe²⁺ ratio and enhanced chemisorbed surface oxygen (O_α); iv. the oxygen mobility and the surface acidity were promoted. Overall, the selective acid leaching is an efficient method to activate RM for the SCR reaction. The RM based catalysts can be an alternative for SCR technology.

Parent, alkylated, oxygenated and nitro polycyclic aromatic hydrocarbons from raw coal chunks and clean coal combustion: Emission factors, source profiles, and health risks

Residential coals are still inevitable using in developing areas in China. Clean coal briquettes, normally using alkaline substance such as lime or red mud (RM) as the additive, were helpful in pollution emission reduction even without changes of stoves. Studies of atmospheric polycyclic aromatic hydrocarbons (PAHs) emission characteristics from RM clear coal combustion were limited. In this study, emission factors (EFs), sources profiles, and health risks of polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 were investigated for raw coal chunks and clean coal (with red mud) through combustion experiments. EFs of total PAHs were found to be 160.1 ± 100.9 mg·kg^-1 and 19.4 ± 6.1 mg·kg^-1 for bituminous and anthracite raw coal chunks (B-C and A-C), respectively. EFs values were highest for parent PAHs (p-PAHs), followed by oxygenated PAHs (o-PAHs), alkylated PAHs (a-PAHs), and nitro PAHs (n-PAHs). EFs of p-PAHs account for 80% and 52% of total PAHs emissions for B-C and A-C, respectively, while those for o-PAHs are 22.9% and 44.9%, demonstrating residential coal combustion as a significant primary source for p-PAHs and o-PAHs. Clean coals were developed through cold-press technology with red mud (RM) as additive, and clean coals with RM contents of 10% are referred to as B-10% (bituminous) and A-10% (anthracite). Compared to raw coals chunks, EFs were reduced from 128.1, 2.5, 29.3 mg·kg^-1 and 161.8 μg·kg^-1 to 83.5, 1.3, 16.4 mg·kg^-1 and 102.2 μg·kg^-1 by B-10%, and from 10.1, 0.6, 8.7 mg·kg^-1 and 20.6 μg·kg^-1 to 11.9, 0.2, 2.4 mg·kg^-1 and 15.3 μg·kg^-1 by A-10% for p-PAHs, o-PAHs, a-PAHs and n-PAHs, respectively. Diagnostic ratios of 5-Nitroacenaphthene / Acenaphthene (0.02-0.05 for coal, 0.0002 for biomass) can be used to separate residential coal and biomass burning in source analysis. When B-C was replaced by B-10%, both noncancer (0.58 to 0.33 for male, 1.65 to 0.95 for female in hazard quotient) and cancer risks (5.68 × 10^-4 to 2.73 × 10^-4 for male, 2.63 × 10^-3 to 1.27 × 10^-3 for female) can be reduced. o-PAHs should be paid more attention because of its high cancer risks caused by 6H-Benzo(C,D)Pyrene-6-One (1.74 × 10^-5 for male, 8.07 × 10^-5 for female), which are even more than the total risks caused by n-PAHs (3.59 × 10^-7 for male, 1.66 × 10^-6 for female). Results from this study highlighted the environment and health effects of PAHs originated from residential coal combustion, and proposed an effective way by using clean coal to alleviate the associated negative impacts.

Influence of phosphorus content on properties and performance of NiW nanocatalyst supported on activated red mud in atmospheric diesel hydrodesulfurization

The influence of phosphorus promoter addition on structural properties and hydrodesulfurization activity of NiW nanocatalysts supported on activated red mud, called NiW/P-ARM, was studied at atmospheric pressure. Before red mud usage, it was treated by Pratt and Christoverson technique and then NiW/P-ARM nanocatalysts with different phosphorus loadings were prepared by impregnation technique. The prepared samples were characterized by XRF, XRD, FESEM, BET, FTIR and H₂-TPR analyses. Base on the obtained results, XRF analysis indicated that activation process remarkably decreased Ca and Na content in the red mud. XRD results indicated the high dispersion of the tungstate, nickel and active phase (NiWO₄) species on the surface of activated red mud support. FESEM analysis illustrated that all particles of NiW/P-ARM were less than 100 nm. TPR measurements revealed that phosphorus-promoted nanocatalysts had higher reduction potentials than nanocatalyst without promoter. The catalytic ability of synthesized nanocatalysts was investigated in a fixed bed reactor at atmospheric pressure and 380 °C using Iso diesel and light diesel as the reaction feeds. It was found that NiW/P-ARM with 1.5 wt.% prompter showed higher activity for hydrodesulfurization process and further addition of P promoter decreased the catalytic activity that may be due to the decrease in surface area or agglomeration particles.

Low temperature benzene oxidation over copper–silver catalyst: roles of copper oxide and silver on cerium–zirconium mixed oxide

The synergetic effects of the non-PGM catalytic components enabled complete benzene oxidation at low temperature, below 200 °C.

Mn-Doped material synthesized from red mud and rice husk ash as a highly active catalyst for the oxidation of carbon monoxide and p-xylene

Red muad and rice husk ash were treated without neutralization by acid to produce a support material (RR).

Application of Red Mud in Wastewater Treatment

Red mud (RM) is an industrial waste produced in large amounts during alumina extraction from bauxite. Its disposal generates serious environmental pollution due to high alkalinity. Therefore, a strategy for the effective utilization of RM must be developed. For instance, RM may be transformed into useful products, such as adsorbents. Given its high concentrations of aluminum oxides, iron oxides, titanium oxides, silica oxides, and hydroxides, RM may be developed as a cheap adsorbent for the removal of various ions from aqueous solution and soils (e.g., metal and non-metal ions, phenolic compounds, and dyes) and waste gas purification (sulfide and carbide). This review summarizes the background, properties, and applications of RM as an adsorbent. Proper approaches of removing metal and non-metal elements from wastewater are also systematically reviewed and compared. Emphasis is placed on the surface modification of RM to obtain high adsorption. Finally, the scope for future research in this area for RM is discussed in depth.

Co-pyrolysis of lignin and plastics using red clay as catalyst in a micro-pyrolyzer

In the current study, low-density polyethylene and polystyrene were co-pyrolyzed with dealkaline lignin in a micro-reactor at 500 °C with and without low-cost red clay catalyst. The products were analyzed with GC-MS/FID to quantify phenolic compounds, alkanes and alkenes. The synergistic effect between plastics and lignin was studied by comparing the carbon yield of compounds from co-pyrolysis with that from individual pyrolysis. The co-pyrolysis of lignin and polystyrene was also performed at 600, 700 and 800 °C to examine the effect of pyrolysis temperature. The study explores a novel approach to enhance lignin depolymerization with red clay catalyst while utilizing waste plastics.

Accelerated crystallization of magnetic 4A-zeolite synthesized from red mud for application in removal of mixed heavy metal ions

To cope with the increasing environmental issues of red mud, an integrated technological route for its comprehensive utilization was developed through the extraction of valuable components and the synthesis of magnetic 4A-zeolite. To accelerate the crystallization process of the synthesized 4A-zeolite, sodium chloride (NaCl) was innovatively employed under hydrothermal treatment. The effects of various parameters, including mass ratio of red mud/NaOH, alkali fusion temperature, alkali fusion time and molar ratio of NaCl/Al₂O₃, were systematically investigated. The results showed that approximately 81.0% Al, 76.1% Si and 95.8% Fe were utilized from red mud using alkali fusion and acid leaching methods. The optimal conditions of the alkali fusion process were determined as: mass ratio of red mud/NaOH = 1/2, alkali fusion temperature of 800 °C, and time of 90 min. Furthermore, when the molar ratio of NaCl/Al₂O₃ was kept at 1.5, the crystallization time reduced from 240 min to 150 min, and particle size distributions narrowed from 20-100 μm to 1-10 μm. The practical applications in removal of mixed heavy metal ions (Zn²⁺, Cu²⁺, Cd²⁺, Ni²⁺, and Pb²⁺) from wastewater indicated that the as-synthesized magnetic 4A-zeolite is a promising candidate for heavy metals adsorption.

Preparation of a new Fenton-like catalyst from red mud using molasses wastewater as partial acidifying agent

Using molasses wastewater as partial acidifying agent, a new Fenton-like catalyst (ACRM _sm ) was prepared through a simple process of acidification and calcination using red mud as main material. With molasses wastewater, both the free alkali and the chemically bonded alkali in red mud were effectively removed under the action of H₂SO₄ and molasses wastewater, and the prepared ACRM _sm was a near-neutral catalyst. The ACRM _sm preparation conditions were as follows: for 3 g of red mud, 9 mL of 0.7 mol/L H₂SO₄ plus 2 g of molasses wastewater as the acidifying agent, calcination temperature 573 K, and calcination time 1 h. Iron phase of ACRM _sm was mainly α-Fe₂O₃ and trace amount of carbon existed in ACRM _sm . The addition of molasses wastewater not only effectively reduced the consumption of H₂SO₄ in acidification of red mud but also resulted in the generation of carbon and significantly improved the distribution of macropore in prepared ACRM _sm . It was found that near-neutral pH of catalyst, generated carbon, and wide distribution of macropore were the main reasons for the high catalytic activity of ACRM _sm . The generated carbon and wide distribution of macropore were entirely due to the molasses wastewater added. In degradation of orange II, ACRM _sm retained most of its catalytic stability and activity after five recycling times, indicating ACRM _sm had an excellent long-term stability in the Fenton-like process. Furthermore, the performance test of settling showed ACRM _sm had an excellent settleability. ACRM_sm was a safe and green catalytic material used in Fenton-like oxidation for wastewater treatment.

Selective recovery of vanadium and scandium by ion exchange with D201 and solvent extraction using P507 from hydrochloric acid leaching solution of red mud

D201 resin and P507 extractant diluted with sulfonated kerosene were used to respectively separate vanadium and scandium, and impurity ions from hydrochloric acid leaching solution of red mud. More than 99% of vanadium was selectively adsorbed from the hydrochloric acid leaching solution under the conditions of pH value of 1.8, volume ratio of leaching solution to resin of 10, and flow rate of 3.33 mL/min. Maximum extraction and separation of scandium was observed from the acid leaching solution at an aqueous pH value of 0.2. More than 99% of scandium can be selectively extracted using 15% P507, 5% TBP at the aqueous solution/organic phase (A/O) ratio of 10:1 for 6 min. The loaded organic phase was washed with 0.3 mol/L sulfuric acid, wherein most impurities were removed. After the process of desorption or stripping, precipitation, and roasting, high-purity V₂O₅ and Sc₂O₃ were obtained. Finally, a conceptual flow sheet was established to separate and recover vanadium and scandium from red mud hydrochloric acid leaching solution.

Preparation and application of acidified/calcined red mud catalyst for catalytic degradation of butyl xanthate in Fenton-like process

Acidified/calcined red mud (ACRM), a novel catalyst used in Fenton-like process, was prepared by acidification and calcination of red mud (RM). Catalyst characterization showed that iron phase of ACRM was mainly α-Fe2O3 and ACRM was a porous material with rough surface and loose structure. Degradation of butyl xanthate in Fenton-like process catalyzed by ACRM was investigated. Butyl xanthate was effectively degraded, and the degradation of butyl xanthate was well fitted by second order kinetic model. ACRM had an excellent long-term stability in a Fenton-like process. The possible mechanisms of hydroxyl radical production and butyl xanthate degradation in a Fenton-like process catalyzed by ACRM were presented.