Treatment of Arsenic Contaminated Groundwater Using Calcium Impregnated Granular Activated Carbon in a Batch Reactor: Optimization of Process Parameters

This paper is an experimental investigation into the removal of arsenic species from simulated groundwater by adsorption onto Ca²⁺ impregnated granular activated carbon (GAC‐Ca) in the presence of impurities like Fe and Mn. The effects of adsorbent concentration, pH and temperature on the percentage removal of total arsenic (As(T)), As(III) and As(V) have been discussed. Under the experimental conditions, the optimum adsorbent concentration of GAC‐Ca was found to be 8 g/L with an agitation time of 24 h, which reduced As(T) concentration from 188 to 10 μg/L. Maximum removal of As(V) and As(III) was observed in a pH range of 7–11 and 9–11, respectively. Removal of all the above arsenic species decreased slightly with increasing temperature. The presence of Fe and Mn increased the adsorption of arsenic species. Under the experimental conditions at 30°C, the maximum percentage removals of As(T), As(III), As(V), Fe, and Mn were found to be ca. 94.3, 90.6, 98.0, 100 and 63%, respectively. It was also observed that amongst the various regenerating liquids used, a 5 N H₂SO₄ solution exhibited maximum regeneration (ca. 91%) of the spent GAC‐Ca.     

Arsenic — a Review. Part II: Oxidation of Arsenic and its Removal in Water Treatment

In natural waters arsenic normally occurs in the oxidation states +III (arsenite) and +V (arsenate). The removal of As(III) is more difficult than the removal of As(V). Therefore, As(III) has to be oxidized to As(V) prior to its removal. The oxidation in the presence of air or pure oxygen is slow. The oxidation rate can be increased by ozone, chlorine, hypochlorite, chlorine dioxide, or H₂O₂. The oxidation of As(III) is also possible in the presence of manganese oxide coated sands or by advanced oxidation processes. Arsenic can be removed from waters by coprecipitation with Fe(OH)₃, MnO₂ or during water softening. Fixed‐bed filters have successfully been applied for the removal of arsenic.The effectiveness of arsenic removal was tested in the presence of adsorbents such as FeOOH, activated alumina, ferruginous manganese ore, granular activated carbon, or natural zeolites. Other removal technologies are anion exchange, electrocoagulation, and membrane filtration by ultrafiltration, nanofiltration or reverse osmosis.     

REE in the Great Whale River estuary, northwest Quebec

We report rare earth element (REE) concentrations of a longitudinal profile within the estuary of the Great Whale River in northwest Quebec and in Hudson Bay. All of the measured REE have concentrations less than those predicted by conservative mixing of seawater and river water, demonstrating removal of the REE from solution. REE removal is rapid, occurring primarily at salinities less than 2‰. Removal of the REE is greatest for the light REE, and ranges from about 7% for the light REE to no more than 40% for the heavy REE. Fe removal is essentially complete at low salinity. The shape of the Fe and REE vs. salinity profiles is not consistent with a simple model of destabilization and coagulation of iron and REE-bearing colloidal material. A linear relationship between the activity of free ion REE³⁺ and pH is consistent with a simple ion-exchange model for REE removal.Surface and subsurface samples of Hudson Bay seawater are characterized by high REE concentrations and high La/Yb relative to average seawater. The subsurface sample has a Nd concentration of 100 pmol/kg and an ε_Nd of −29.3 ± 0.3. These characteristics are consistent with the high REE concentration, high La/Yb, and low ε_Nd of river inputs into Hudson Bay. These results indicate that rivers draining the Canadian Shield are a major source of non-radiogenic Nd and REE to the Atlantic Ocean. We estimate that outflow of water from Hudson Bay to the Labrador Sea could supply ≈ 30% of the non-radiogenic Nd in North Atlantic Deep Water.     

The performance of constructed wetlands for,wastewater treatment: a case study of Splash wetland in Nairobi Kenya

The performance of a constructed wetland for wastewater treatment was examined for four months (December 1995 to March 1996). The study area, hereby referred to as the Splash wetland, is approximately 0·5 ha, and is located in the southern part of Nairobi city. Splash wetland continuously receives domestic sewage from two busy restaurants. Treated wastewater is recycled for re‐use for various purposes in the restaurants. Both wet and dry season data were analysed with a view of determining the impact of seasonal variation on the system performance. The physical and chemical properties of water were measured at a common intake and at series of seven other points established along the wetland gradient and at the outlet where the water is collected and pumped for re‐use at the restaurants. The physico‐chemical characteristics of the wastewater changed significantly as the wastewater flowed through the respective wetland cells. A comparison of wastewater influent versus the effluent from the wetland revealed the system's apparent success in water treatment, especially in pH modification, removal of suspended solids, organic load and nutrients mean influent pH = 5·7 ± 0·5, mean effluent pH 7·7 ± 0·3; mean influent BOD₅ = 1603·0 ± 397·6 mg/l, mean effluent BOD₅ = 15·1 ± 2·5 mg/l; mean influent COD = 3749·8 ± 206·8 mg/l, mean effluent COD = 95·6 ± 7·2 mg/l; mean influent TSS = 195·4 ± 58·7 mg/l, mean effluent TSS = 4·7 ± 1·9 mg/l. As the wastewater flowed through the wetland system dissolved free and saline ammonia, NH₄⁺, decreased from 14·6 ± 4·1 mg/l to undetectable levels at the outlet. Dissolved oxygen increased progressively through the wetland system. Analysis of the data available did not reveal temporal variation in the system's performance. However, significant spatial variation was evident as the wetland removed most of the common pollutants and considerably improved the quality of the water, making it safe for re‐use at the restaurants. Copyright © 2001 John Wiley & Sons, Ltd.     

Designing the Mineralization of a Wastewater Sample from a Coating Industry

Design of Fenton and photo‐Fenton reactions was partially automated by using sequential injection analysis (SIA) and response surface methodology for the treatment of a wastewater sample from a coatings industry. The extension of both Fenton and photo‐Fenton reactions was evaluated by the percentage of total organic carbon (TOC) remaining in solution after 15 min of reaction. Use of small volumes of sample and reagents, as well as easy solution handling, were the remarkable features of the proposed system. The highest percentage of TOC removal (79%) was obtained by the photo‐Fenton reaction at the following initial mass‐based concentration ratios: H₂O₂/TOC = 10, H₂O₂/FeSO₄ = 50, and pH 2.5. The best result for Fenton reaction indicated a TOC removal of only 45%, obtained at H₂O₂/initial TOC = 20, H₂O₂/FeSO₄ = 30, and pH 2.5. The SIA system was designed to dispense reagents to the sample flasks and to drive the sample intended to photo‐Fenton reaction through a homemade photo‐reactor. Modifications in chemical parameters of the reactions were achieved via the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve.     

Protonated Hydroxylamine-Assisted Iron Catalytic Activation of Persulfate for the Rapid Removal of Persistent Organics from Wastewater

This research aims at optimizing the effects of processing conditions, salts, natural organic materials, and water matrices quality on the effectiveness of the Fe(II)/K₂S₂O₈/hydroxylamine process in the degradation of pararosaniline. Assisting the Fe(II)/KPS (potassium persulfate) treatment with protonated hydroxylamine (H₃NOH⁺) increases the degradation rate of pararosaniline by more than 100%. Radical scavenger experiments show that the SO₄^●− radical dominates pararosaniline degradation in the Fe(II)/KPS system, whereas ^●OH is the dominant reactive species in the presence of H₃NOH⁺. The disparity in pararosaniline removal effectiveness upon the Fe(II)/KPS/H₃NOH⁺ and Fe(II)/KPS systems gets more significant with increasing reactants doses (i.e., H₃NOH⁺, H₂O₂, Fe(II)) and solution pH (2–7). Interestingly, H₃NOH⁺ increased the working pH to 6 instead of pH 4 for the Fe(II)/KPS process. Moreover, mineral anions such as Cl⁻, NO₃⁻, NO₂⁻, and SO₄⁻ (up to 10 × 10⁻³ m ) do not affect the efficiency of the Fe(II)/KPS/H₃NOH⁺ process. In contrast, acid humic decreases the performance of the process by ≈20%. In natural mineral water, treated wastewater, and river water samples, the Fe(II)/KPS/H₃NOH⁺ process maintains higher degradation performance (≈95%), whereas the process efficiency is greatly amortized in seawater. The efficiency of the Fe(II)/KPS process was drastically decreased in the various water matrices.     

Removal of Arsenic from Simulated Groundwater Using GAC‐Ca in Batch Reactor: Kinetics and Equilibrium Studies

This paper deals with kinetics and equilibrium studies on the adsorption of arsenic species from simulated groundwater containing arsenic (As(III)/As(V), 1:1), Fe, and Mn in concentrations of 0.188, 2.8, and 0.6 mg/L, respectively, by Ca²⁺ impregnated granular activated charcoal (GAC‐Ca). Effects of agitation period and initial arsenic concentration on the removal of arsenic species have also been described. Although, most of the arsenic species are adsorbed within 10 h of agitation, equilibrium reaches after ～24 h. Amongst various kinetic models investigated, the pseudo second order model is more adequate to explain the adsorption kinetics and film diffusion is found to be the rate controlling step for the adsorption of arsenic species on GAC‐Ca. Freundlich isotherm is adequate to explain the adsorption equilibrium. However, empirical polynomial isotherm gives more accurate prediction on equilibrium specific uptakes of arsenic species. Maximum specific uptake (q_max) for the adsorption of As(T) as obtained from Langmuir isotherm is 135 µg/g.     

Optimization of a Photo‐assisted Fenton Oxidation Process: A Statistical Model for MDF Effluent Treatment

In the present study, the effects of initial COD (chemical oxygen demand), initial pH, Fe²⁺/H₂O₂ molar ratio and UV contact time on COD removal from medium density fiberboard (MDF) wastewater using photo‐assisted Fenton oxidation treatment were investigated. In order to optimize the removal efficiency, batch operations were carried out. The influence of the aforementioned parameters on COD removal efficiency was studied using response surface methodology (RSM). The optimal conditions for maximum COD removal efficiency from MDF wastewater under experimental conditions were obtained at initial COD of 4000 mg/L, Fe²⁺/H₂O₂ molar ratio of 0.11, initial solution pH of 6.5 and UV contact time of 70 min. The obtained results for maximum COD removal efficiency of 96% revealed that photo‐assisted Fenton oxidation is very effective for treating MDF wastewater.     

Glutamic Acid Modified Fenton System for Degradation of BTEX Contamination

The present study employed a modified Fenton system that aims to extend the optimum pH range towards neutral conditions for studying the oxidation of benzene, toluene, ethyl benzene, xylenes (BTEX) using glutamic acid (Glu) as an iron chelator. Addition of 20 mM Glu greatly enhanced the oxidation rate of BTEX in modified Fenton system at pH 5–7. A rapid mass destruction (>97% after 1 h) of BTEX as a water contaminant carried out in the presence of 500 mM H₂O₂, 10 mM Fe²⁺, and 20 mM Glu at pH 5 could be shown. The efficiency of this modified Fenton's system for mass destruction of BTEX in contaminated water was measured to estimate the impact of the major process variables that include initial concentrations of soluble Fe, H₂O₂, Glu (as metal chelating agent), and reaction time.     

Treatment of Refractory Organics Contained in Actual Agro‐Industrial Wastewaters by UV/H2O2

In this work, the treatment of actual agro‐industrial wastewaters (IWW) by a UV/H₂O₂ process has been investigated. The aqueous wastes were received from industrial olive oil mills and then treated by laboratory scale physicochemical methods, i. e., coagulation using ferrous and aluminum sulfate, decantation, filtration and adsorption on activated carbon. These wastes are brown colored effluents and have a residual chemical oxygen demand (COD) in the range of 1800 to 3500 mgO₂ L^–1, which cannot be further eliminated with physicochemical processes. The UV/H₂O₂ treatments were carried out under monochromatic irradiation at 254 nm using a thermostated reactor equipped with a mercury vapor lamp located in an axial position. The effects of initial H₂O₂ concentration, initial COD, pH and temperature have been studied in order to determine the optimum conditions for maximum color and COD removals. The experimental results reveal the suitability of the UV/H₂O₂ process for both removal of high levels of COD and effectively decolorizing the solution. In particular, 95% of color removal and 90% of COD removal were obtained under conditions of pH = 5 and 32°C using 2.75 g H₂O₂ g^–1 COD L^–1 during 6 h of UV‐irradiation. The treatment is unaffected by pH over the range 2 to 9. In addition, the COD removal is improved by increasing the temperature, whereas the color removal has not been affected by this parameter. The results show that the hydroxyl radicals generated from the catalytic decomposition of H₂O₂ by UV‐irradiation of the solution could be successfully used to mineralize the organics contained in IWW. The mineralization of the organics seems to occur in three main sequential steps: the first is the rapid decomposition of tannins leading to aromatic compounds, which are confirmed by the decolorization of the IWW; the second step corresponds to the oxidation of aromatics leading to aliphatic intermediates, which occurs by the cleavage of an aromatic ring, and is established by the removal of aromatics, and the final step is the slow oxidation of the aliphatic intermediates, which is measured by the COD removal.     

Turbidity Removal from Wastewaters of Natural Stone Processing by Coagulation/Flocculation Methods

The effectiveness of coagulation (at pH values of 6, 7.5, and 9), flocculation (at pH 9), and coagulation plus flocculation (at pH 9) on turbidity removal from natural stone (travertine) processing wastewaters (NSPW) were examined by applying classical sedimentation tests. FeCl₃·6 H₂O, AlCl₃, and Al₂(SO₄)₃·16 H₂O were used as coagulants and a polyacrylamide based anionic polymer was used as the flocculant. In this way, it was found that the coagulation method alone was not sufficient to purify NSPW, whereas flocculation and coagulation plus flocculation methods provided superior purification. Among the coagulants used, AlCl₃ gave the best result in terms of turbidity removal by coagulation from NSPW at pH 6 and 9, whereas the turbidity removal performances of the three coagulants were almost identical at pH 7.5. In addition, relatively low pH (i. e., pH 6) improved the purification performance of all coagulants. During coagulation of NSPW at pH 6, a charge neutralization mechanism played a decisive role in turbidity removal. However, in neutral (pH 7.5) and slightly basic (pH 9) media, a sweep coagulation mechanism was predominant. For flocculation of NSPW, the basic mechanism comprised of polymer bridging.     

Color Removal from Synthetic Textile Wastewater by Sono‐Fenton Process

In this study, the oxidative decolorization of C.I. reactive yellow 145 (RY 145) from synthetic textile wastewater including RY 145 and polyvinyl alcohol by Fenton and sono‐Fenton processes which are the combination of Fenton process with ultrasound has been carried out. The effects of some operating parameters which are the initial pH of the solution, the initial concentration of Fe²⁺, H₂O₂, and the dye, temperature, and agitation speed on the color and chemical oxygen demand (COD) removals have been investigated. The optimum conditions have been found as [Fe²⁺] = 20 mg/L, [H₂O₂] = 20 mg/L, pH 3 for Fenton process and [Fe²⁺] = 20 mg/L, [H₂O₂] = 15 mg/L, pH 3 for sono‐Fenton process by indirectly sonication at 35 kHz ultrasonic frequency and 80 W ultrasonic power. The color and COD removal efficiencies have been obtained as 91 and 47% by Fenton process, and 95 and 51% by sono‐Fenton processes, respectively. Kinetic studies have been performed for the decolorization of RY 145 under optimum conditions at room temperature. It has been determined that the decolorization has occurred rapidly by sono‐Fenton process, compared to Fenton process.     

Adsorption of Complex Pollutants from Aqueous Solutions by Nanocomposite Materials

In view of water pollutants becoming more complex, both anionic and cationic pollutants need to be removed. The multi‐pollutants simultaneous removal is paid more and more attention. Hence, development composite materials for treatment complex wastewater are the aim of this study. In this research, iron–nickel nanoparticles deposited onto aluminum oxide (α‐Al₂O₃) and carbon nanotubes (CNTs) to form nanocomposite materials Fe–Ni/Al₂O₃ and Fe–Ni/CNTs, respectively, were used as adsorbents. The adsorption capacities of Fe–Ni/Al₂O₃ and Fe–Ni/CNTs for AO7, HSeO, and Pb²⁺ were observed to be 5.46, 8.28, 27.02, and 25.6 mg/g, 15.29 and 17.12 mg/g, separately. The composite materials with negative charges were superior in adsorption of anionic pollutants. Using orthogonal experimental design and analysis of variance to co‐treat dye AO7, HSeO and Pb²⁺ in aqueous solutions, seven testing factors were included: (1) adsorbent types, (2) amount of iron, (3) solution pHs, (4) AO7 concentrations, (5) Pb²⁺ concentrations, (6) HSeO concentrations and (7) reaction time. The experimental results showed that the removal of complex pollutants AO7, HSeO, and Pb²⁺ on Fe–Ni/CNTs could reach up to 90% in the optimal treatment conditions. When using Fe–Ni/CNTs as the adsorbent, the sorption isothermals were well fitted in the Freundlich isotherm, and R² could reach up to 0.98.     

Structure refinement of astrophyllite

The crystal structure of astrophyllite K₂Na(Fe, Mn, Mg,□)₇[Ti₂(Si₄O₁₂)₂|O₃](OH, F)₄ has been refined. The dimensions of the triclinic unit cell are: a = 0.5359(2) nm,b = 1.1614(4) nm, c = 1.1861(4) nm, α= 113.16(2)°, β= 103.04(2)°,γ= 94.56(2)°,V = 0.6495(5) nm³, Z= 1, space group P1, R=0.057 for 5308 reflections |F_o|>3σ|F_o|. According to structural and compositional differences the monoclinic astrophyllite K₂NaNa(Fe, Mn)₄Mg₂Ti2[Si₄O₁₂]₂(OH)₄(OH, F)₂ and astrophyllite should be considered as two different mineral species. Astrophyllite, monoclinic astrophyllite, bafertisite and lamprophyllite contain heteropolyhedral sheets which topologically are related with Si, O sheets of mica where one or several SiO₄ tetrahedra are replaced by TiO _n polyhedra. Therefore this heterophyllotitanosilicate series represents a kind of functional substitution in inorganic crystals.     

Electrocoagulation/Electroflotation Process for Removal of Organics and Microplastics in Laundry Wastewater

In the present research, laundry wastewater treatment is studied using the electrocoagulation/electroflotation process. For the optimization of treatment conditions such as electrode type (Al–Al, Al–Fe, Fe–Fe, and Fe–Al), initial pH (5–9), current (0.54–2.16 A), and application time (15–60 min), response surface methodology is used. Removal efficiencies of chemical oxygen demand (COD), color, anionic surfactant, microplastic, and phosphate are studied. It is determined that the most effective removal is obtained with 2.16 A current, pH 9, and 60 min reaction time using Fe–Al electrode. Here, 91%, 94%, 100%, and 98% removal efficiencies are achieved for COD, surfactant, color, and microplastic, respectively. The operating cost of the combined process is calculated as $1.32 m^?3 for the optimum removal parameters. The adsorption kinetics study shows that the removal follows second‐order kinetics. The laboratory‐scale test results indicate that the electrocoagulation/electroflotation process is feasible for the treatment of laundry wastewater.     

Adsorption of Cadmium Ions from Aqueous Solution Using Granular Activated Carbon and Activated Clay

The present study was aimed at removing cadmium ions from aqueous solution through batch studies using adsorbents, such as, granular activated carbon (GAC) and activated clay (A‐clay). GAC was of commercial grade where as the A‐clay was prepared by acid treatment of clay with 1 mol/L of H₂SO₄. Bulk densities of A‐clay and GAC were 1132 and 599 kg/m³, respectively. The surface areas were 358 m²/g for GAC and 90 m²/g for A‐clay. The adsorption studies were carried out to optimize the process parameters, such as, pH, adsorbent dosage, and contact time. The results obtained were analyzed for kinetics and adsorption isotherm studies. The pH value was optimized at pH 6 giving maximum Cd removal of 84 and 75.2% with GAC and A‐clay, respectively. The adsorbent dosage was optimized and was found to be 5 g/L for GAC and 10 g/L for A‐clay. Batch adsorption studies were carried out with initial adsorbate (Cd) concentration of 100 mg/L and adsorbent dosage of 10 g/L at pH 6. The optimum contact time was found to be 5 h for both the adsorbents. Kinetic studies showed Cd removal a pseudo second order process. The isotherm studies revealed Langmuir isotherm to better fit the data than Freundlich isotherm.     

Chemistry of solutions from the 13°N East Pacific Rise hydrothermal site

Ten samples were recovered by the submersible “Cyana” submersible from two groups of hydrothermal vents located 2600 m deep along the East Pacific Rise at 13°N. The maximum measured temperature was 317°C and minimum pH 3.8. A systematic determination of major and trace elements has been carried out and mixing lines between a high-temperature component (HTC) and seawater are observed. The water chemistry of the HTC slightly differs for several elements at the two sites. This HTC is deprived of SO₄ and Mg and is greatly enriched in most other species. Maximum concentrations are (in units per kg):Cl = 0.72mol; Br = 1.1mmol; Na = 0.55mol; K = 29mmol; Rb = 14 μmol; Ca = 52mmol; Sr = 170 μmol; Mn = 750 μmol; Fe = 1mmol; Al = 15 μmol; Si = 21mmol. For many elements, the magnitude of the anomaly relative to seawater does not compare with the results obtained from the Galapagos or East Pacific Rise 21°N. The enrichment of cations relative to seawater is likely related to the huge Cl excess through charge balance. TheBr/Cl ratio is close to that for seawater. However, it is not clear whether the Cl excess is due to gas release or basalt hydration (formation of amphibole chlorite or epidote).P-T dependence of SiO₂ solubility suggests that water-rock interaction last occurred at a depth in excess of 1 km below the sea floor. A mixing line of⁸⁷Sr/⁸⁶Sr vs. Mg/Sr demonstrates that the HTCs have a nearly identical⁸⁷Sr/⁸⁶Sr ratio of 0.7041 for both sites. A water/rock ratio of about 5 is inferred, which differs from the 1.5 value obtained at 21°N.     

Batch and Continuous Design of a Full‐Scale Treatment Facility for Removing Dissolved Natural Organic Matter

Batch and continuous flow adsorption experiments are carried out and the design of a full‐scale facility for removing dissolved natural organic matter (DNOM) from Catalan Lakewater is demonstrated. The adsorption efficiency is proportional to the temperature and the amount of adsorbent unlike pH increase. The highest DNOM removal rate is obtained at 35 °C, pH 4, and an adsorbent amount of 0.8 g L^?1. Optimum contact time for batch studies is 60 min at equilibrium. Correlation constants (r) of Langmuir and Freundlich isotherms are 0.8905 and 0.9739, respectively. Based on the Freundlich isotherm, the highest adsorption capacity (q_max) obtained is 2.44 and 6.01 mg DNOM/g granulated activated carbon (GAC) for raw and enriched water, respectively. Consequently, the effects of adsorbent amount, bed depth, empty bed contact time, and organic loading on removal performance are investigated in the rapid small‐scale column test (RSSCT) columns. The targeted effluent concentration of 1 mg DNOM/L can easily be achieved in the columns. At the design capacity of the facility, 15 adsorption columns with dimensions of 7 m height, 4.33 m diameter, and 22 days of operation cycle are required to remove DNOM from raw water.     

Sorption of Eu<Superscript>3+</Superscript>onto nano-size silica-water interfaces

The sorption of Eu species onto nano-size silica-water interfaces is investigated at pH range of 1―8.5 and the initial Eu concentrations (C_Eu) of 2×10⁻⁵, 2×10⁻⁴ and 2×10⁻³ M using fluorescence spectroscopy. The sorption rate of Eu is initially low, but significantly increases at pH > 4. For the initial C_Eu of 2×10⁻⁵, 2×10⁻⁴ and 2×10⁻³ M, the dissolved Eu species are completely sorbed onto silica-water interfaces at pH = 4.75, −5.8 and 6.6, respectively, with the respective sorption densities of −1.58×10⁻⁸, 1.58×10⁻⁷ and 1.58×10⁻⁶ mol/m². The sorbed Eu species at pH < 6 is aquo Eu³⁺, which is sorbed onto silica-water interfaces as an outer-sphere complex at pH < 5, but may be sorbed as an inner-sphere bidentate complex at 5 < pH < 6, due to the decrease of the N_H2O to −6 at pH = 6. At pH = 6 – 8, Eu(OH)²⁺, Eu(CO₃)⁺and Eu(CO₃)₂ ⁻ form in the solutions, and Eu(CO₃)⁺is dominant at pH = −7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes or multi-nuclear pre-cipitates.     

Detoxification of Arsenite through Adsorption and Oxidative Transformation on Pyrolusite

Adsorption and oxidative transformation processes critically affect the mobility and toxicity of arsenic (As) in the environment. In this study, the detoxification of arsenite through adsorption and oxidation by pyrolusite was systematically investigated. Disappearance of aqueous As(III) in the solution can be efficiently achieved using pyrolusite. The As(III) oxidative transformation product arsenate or As(V) was obtained both in the solution and on the pyrolusite surface. The arsenic species adsorbed on pyrolusite exist in two forms: As(III) and As(V). Furthermore, over 64.8% of the adsorbed As cannot be desorbed. They were fixed more stably in the structure of the mineral to achieve a safer removal. Lower As(III) initial concentration increased As(III) detoxification rates. Elevating the reaction pH from 4.5 to 7.9 elicited a slight effect on the disappearance rate of As(III). Efficient As(III) detoxification can be achieved by pryrolusite within the studied pH range. The addition of low‐molecular‐weight carboxylic acids decreased the detoxification rate of As(III) through competition for active sites on pyrolusite. Co‐existing divalent metal ions, such as Ca²⁺, Ni²⁺, and Mn²⁺, also decreased the detoxification rate of As(III). However, the trivalent ion Cr³⁺ largely increased the detoxification rate through co‐precipitation and adsorption processes.