Continuous Flow Experiments Research Articles

Unveiling synergistic enhancement mechanism of nitrogen removal in surface flow constructed wetlands: Utilizing iron scraps and elemental sulfur as integrated electron donors

Lacking electron donors generally causes poor denitrification performance in constructed wetlands (CWs). In this study, iron scraps (ISs) and elemental sulfur (S0) were employed as electron donors in different surface flow constructed wetlands (SFCWs): control (C-SF), ISs added (Fe-SF), S0 added (S-SF), and ISs and S0 combined (Fe + S-SF) to investigate the performance and mechanism of nitrogen (N) removal through continuous flow and batch experiments. The impact of hydraulic retention times (HRTs) and temperatures on N removal was explored. The combined use of ISs and S0 significantly improved nitrate (NO3− -N) removal in Fe + S-SF compared to the other SFCWs. During the 3-d HRT at 25 °C, the average NO3− -N removal efficiency in Fe + S-SF reached the highest value of 71.66 ± 12.54%, reducing NO3− -N concentrations from 12.03 mg/L to 3.47 mg/L. The results of the batch experiments revealed an N removal pattern that aligned with the findings of the continuous flow experiment. The microbial community analysis revealed a selective enrichment of key functional genera (e.g., Ferritrophicum and Dechloromonas), contributing to enhanced N removal in Fe + S-SF. These findings suggest that the synergistic use of ISs and S0 can achieve better denitrification efficiency and potentially be utilized for enhanced N removal from low C/N wastewater.

Oxygen vacancies engineering in Mn3O4 for regulating peroxymonosulfate activation and efficient bisphenol A degradation

In this work, oxygen vacancies (VO)-rich Mn3O4 was synthesized via changing reactive solvent. The effects of VO amount on PMS activation mechanism and bisphenol A (BPA) degradation were explored. Introduction of moderate amount of VO in Mn3O4 facilitated charge transfer and the exposure of surface Mn3+ species, which could oxidize BPA. Meanwhile, VO content could affect the PMS adsorption and activation modes. PMS adsorbed on bridged Mn-Mn sites in Mn3O4-x with more VO was likely to extract electrons from BPA to oxidize it directly. SO4•–, •OH, and 1O2 made negligible contributions to BPA degradation due to the presence of these two oxidation processes, but they were effective in the VO-free Mn3O4 system. Mn3O4-x/PMS system had good anti-interference ability in the degradation of BPA in complicated matrixes. The normalization kinetic constant was 103.2 min−1 M−1, which was 8.3 times higher than that of VO-free Mn3O4. The good catalytic activity (BPA = 20 ppm, with a removal ratio of above 90.0% in 180 min) in the continuous-flow experiment further revealed the potential of Mn3O4-x/PMS in practical wastewater applications. This study provides a new method to regulate the amount of VO in Mn3O4 and presents deep insights into the influence of VO on PMS activation.

Efficient one-pot tandem C-C formation reaction catalyzed by a multi-functionalized polyacrylonitrile fiber catalyst

A simple and straightforward method has been proposed in this work to construct a multi-functionalized polyacrylonitrile fiber catalyst containing carboxylic acid, tertiary amine, and quaternary ammonium salt to enable series one-pot C-C bond formation in water. The fiber catalyst was prepared from polyacrylonitrile fiber using a two-step method and characterized using various detection techniques. Furthermore, the activity of multi-functional synergistic catalysts can be controlled by adjusting the ratio of acid and base. It is noteworthy that the polyacrylonitrile fiber catalyst with an acid-base ratio of 3:1 (PANF-ABNCl3/1) exhibited superior catalytic activity and high yield in a variety of C-C generation reactions. Additionally, the PANF-ABNCl3/1 catalyst demonstrated exceptional recyclability (at least 10 times) and performed well in scale-up (7.4g, 96%) and continuous flow experiments (can be used continuously for 7 × 24h) using kettle and tubular fixed bed reactor respectively. These findings suggest that the PANF-ABNCl3/1 catalyst holds promise for industrialization.

Runoff variation alters estuarine sediment microbiome and nitrogen removal processes by affecting salinity

Runoff variations shape the dynamics of the estuarine environmental factors, profoundly influencing the nitrogen cycle in estuarine sediments. However, our understanding of how these changes regulate microbially-mediated nitrogen removal processes remains limited. In this study, the impacts of changes in environmental factors caused by normal and low runoffs on denitrification and anammox in sediments of the Liao River Estuary in China, were investigated, using continuous-flow experiments combined with 15N tracing techniques and molecular methods. Results indicated that denitrification was the main nitrogen removal process in estuarine sediments under both runoff conditions. Elevated salinity under low runoff condition increased the abundance of nitrifying bacteria (Nitrospina, Nitrosomonas and Nitrosomonadaceae), thereby promoting the coupled nitrification-denitrification nitrogen removal process. Furthermore, seawater intrusion under low runoff contributed to dilute nitrite concentrations, resulting in decreased denitrification rates in sediments. Overall, this study highlighted the impacts of runoff variations on biological nitrogen removal process through affecting environmental factors, gene abundance and microbial community in the estuary.

Synergistic catalysis of dual-sites promoted cycloaddition of CO2 with epoxides

This study explores the catalytic efficacy of fluorine-modified 1 wt% copper oxide on MCM-41 (F-1Cu/MCM-41) in carbon dioxide cycloaddition reactions. It delves into reaction mechanisms, active sites, and the practical applicability of the catalyst. Comprehensive examination through in situ diffuse reflectance infrared Fourier transform spectroscopy and other analytical methods substantiated the role of halogen-modified mono-dispersed copper species in carbon dioxide activation and silicon hydroxide sites in epoxide activation, while underscoring the role of Lewis bases and Brønsted acids. Kinetic studies and density functional theory calculations pinpointed carbon dioxide activation as the pivotal step. Furthermore, the catalyst exhibited robust stability and efficiency in continuous flow experiments, sustaining a 99% selectivity towards cyclic carbonate over 150 h. An eco-friendly evaluation confirmed the sustainability of the process, emphasizing its minimal environmental footprint and high efficiency. These results establish fluorine-modified 1 wt% copper oxide on MCM-41 as a formidable candidate for industrial-scale cyclic carbonate production, due to its promising performance and sustainability.

Regeneration of conventional and emerging PFAS-selective anion exchange resins used to treat PFAS-contaminated waters

Anion exchange resins (AERs) have emerged as a promising separation technology to remediate PFAS-contaminated waters due to their improved selectivities and capacities in comparison to legacy activated carbon adsorbents. Presently, site managers choose between AER systems employing resins defined as being ‘regenerable’ with relatively low PFAS selectivity, and PFAS-selective resins that are marketed as ‘single-use’ media intended for disposal upon PFAS breakthrough. However, the potential for these highly-selective adsorbents to be regenerated and/or reused remains poorly characterized. This study presents a comprehensive evaluation of the efficacy of various regenerant solution constituents, mixtures, and operational considerations on the regenerability of both ‘regenerable’ and ‘PFAS-selective’ AERs that were loaded during a pilot treatment study of PFAS-contaminated groundwater. Batch screening of regenerant solution constituents found that both classes of resins may be effectively regenerated using combinations of salt brine and organic cosolvent, with high cosolvent fractions being necessary for PFAS-selective AERs. While neither brine-only nor solvent-only regenerant solutions led to effective PFAS desorption, the efficacy of regeneration with brine/cosolvent mixtures varied with salt type and cosolvent composition. Chloride salts outperformed sulfate and bicarbonate salts, cosolvent efficacy depended on the volume fraction and type used, and highly non-polar solutions led to optimal PFAS desorption. Continuous-flow regeneration experiments showed near-complete PFAS desorption from regenerable AERs using 10 bed volumes (BVs) of 70 % methanolic brine solutions, whereas PFAS-selective resins required more bed volumes (30) of brines with higher methanol content (90 %) or a more hydrophobic cosolvent (n-propanol); increasing regenerant empty-bed contact time had minimal effect on PFAS desorption. > 90 % methanol recovery from the resulting waste regenerant mixtures was accomplished with negligible PFAS contamination using distillation, leaving a minimal volume of a PFAS-concentrated still bottoms waste that may be further treated for PFAS destruction. Life cycle analyses revealed that groundwater treatment using PFAS-selective AERs operated in a regenerable mode have lower environmental impacts and costs than systems using conventional regenerable AERs, and lower treatment costs than systems operated using PFAS-selective resins in a single-use mode. Although counterintuitive, these findings stem from the fact that higher cosolvent requirements for regeneration of PFAS-selective resins lead to greater internal recycling of regenerant solutions and much lower volumes of residual waste still bottoms that require off-site incineration or disposal.

Treatment of antibiotics in mariculture wastewater via phosphate-doped porous coralline carbon nitride/porous mullite honeycomb sunlight-driven photocatalytic system: Morphological control, long-term and continuous flow application

Herein, this study describes a promising sunlight-driven photocatalytic system designed for the elimination of antibiotics (e.g., fluoroquinolones and sulfonamides) in real maricultural wastewater. Phosphate-doped porous coralline carbon nitride (P-CCN), synthesized by controlling morphology from two-dimensional block CN, was immobilized onto porous mullite honeycomb to construct a practical and molding photocatalytic system (P-CCN/PMH). By leveraging its microscopic porous coral structure, P-CCN displayed an augmentation in surface-active sites and a notable inner light refraction effect. This enhancement contributed to the high-efficiency performance of P-CCN/PMH system, producing 8.232 mM·h−1·g−1 H2O2 under sunlight, which was 7.21-fold higher than before modification; and its degradation rate constant to enrofloxacin (0.263 min−1) was 39.31-fold higher. The P-CCN/PMH system demonstrated superior capability in terms of adaptability to a wide concentration range, acid-alkali conditions, mineralization, carbon reduction, and challenging ionic surroundings or water matrices. Crucial superoxide radicals have been confirmed through mass-spectrometric technique and theoretical calculations, leading to ring-opening effects. Long-term and continuous-flow experiments were deeply carried out, validating the commendable competence of the P-CCN/PMH photocatalytic system in simulated wastewater treatment scenarios. Ultimately, the aggregate results highlight valuable insights into coralline materials synthesis and modular catalyst construction, presenting potential for addressing challenges related to environmental antibiotics pollution.

Complete dehalogenation of chloramphenicol by bimetallic alloy Pd-Au nanoparticles in a H2-Based membrane Catalyst-Film reactor

An effective treatment method to achieve complete dehalogenation of halogenated antibiotics is an urgent affair, because partially dehalogenated products remain persistent pollutants and sometimes having higher toxicity than the original antibiotics. This study is the first to achieve complete reductive dechlorination of chloramphenicol (CAP) using bimetallic alloy Pd-Au nanoparticles (Pd-AuNPs) in a hydrogen (H2)-based membrane catalyst-film reactor (H2-MCfR). Compared to mono-Pd nanoparticles (PdNPs), bimetallic alloy Pd-AuNPs gave faster removal and more complete dechlorination of CAP in batch and continuous-flow experiments. Notably, complete CAP dechlorination was achieved with a catalyst film of Pd-AuNPs (mole ratio 1:1) that had negligible catalyst loss in a 20-day continuous operation. LC-MS identified the products of reductive dechlorination, and the dominant pathways differed significantly between PdNPs and Pd-AuNPs. In particular, Pd-AuNPs favored reductive dechlorination, while PdNPs favored reduction of the –NO2 group, which led to partially dechlorinated products that were stable. Density functional theory (DFT) calculations showed how the Au atoms reduced the adsorption energy of reactants, which affected reaction selectivity. Toxicity prediction model confirmed that reducing dechlorination significantly decreased acute toxicity to fish, daphnia and green algae. Thus, the MCfR with Pd-AuNP catalysts offers promise for achieving complete dechlorination of CAP and inspires further studies for other halogenated antibiotics.

A novel redox synergistic mechanism of peroxymonosulfate activation using Pd-Fe3O4 for ultra-fast chlorinated hydrocarbon degradation

Peroxymonosulfate (PMS)-based heterogeneous advanced oxidation processes for chlorinated hydrocarbons (CHCs) removal in groundwater face the challenge of limited degradation ability. In this work, recyclable catalysts composed of Pd and Fe3O4 nanoparticles were synthesized to activate PMS and generate oxidative HO• and SO4•− and reductive H•, simultaneously. The synergistic attack of different active species led to the ultra-fast degradation and mineralization of multiple CHCs. For trichloroethylene (TCE) degradation, the catalysts mass normalized reaction rate constant of Pd-Fe3O4/PMS system (30.85 L g−1 min−1) was one order of magnitude higher than reported PMS activation systems. The d-band center of Pd in Pd-Fe3O4 was close to the Fermi level, indicating that Pd(0) sites of Pd-Fe3O4 was more conducive to the activation of PMS. In addition, PMS attached Fe3O4 sites caused internal electron transfer to Pd(0) for H• generation. Higher than 97 % of CHCs removal efficiency in continuous flow experiment demonstrated the application potential of Pd-Fe3O4/PMS system.

Mechanistic insight into microbial interaction and metabolic pattern of anammox consortia on surface-modified biofilm carrier with extracellular polymeric substances

The extremely slow growth rate of anaerobic ammonia oxidation (anammox) bacteria limits full-scale application of anammox process worldwide. In this study, extracellular polymeric substances (EPS)-coated polypropylene (PP) carriers were prepared for biofilm formation. The biomass adhesion rate of EPS-PP carrier was 12 times that of PP carrier, and EPS-PP achieved significant enrichment of E. coli BY63. The 120-day continuous flow experiment showed that the EPS-PP carrier accelerated the formation of anammox biofilm, and the nitrogen removal efficiency increased by 10.5 %. In addition, the abundance of Candidatus Kuenenia in EPS-PP biofilm was 27.1%. Simultaneously, amino acids with high synthesis cost and the metabolites of glycerophospholipids related to biofilm formation on EPS-PP biofilm were significantly up-regulated. Therefore, EPS-PP carriers facilitated the rapid formation of anammox biofilm and promoted the metabolic activity of functional bacteria, which further contributed to the environmental and economic sustainability of anammox process.

Hardness Removal by A Continuous Flow Electrochemical Reactor from Different Types of Water

The present study focuses on the technique of hardness removal by using a novel reactor performing an electrocoagulation (EC) process. The variation of alkalinity is also recorded. Continuous flow experiments were conducted for Total Hardness (TH) removal using a transparent plastic reactor using aluminum plate electrodes that have holes so that the water flows through the plates in a zigzag way. The influence of various operating parameters such as the number of plates (two and four), flow rate (600, 1000 L/h), and water type (Tigris River & rejected water from Reverse Osmosis system RO) was investigated. The results showed that an increase in the number of electrodes led to an increase in the total hardness removal efficiency. In addition, the increase in the flow rate led to a decrease in the removal efficiency. For the rejected RO water type, the highest hardness removal rate was 16.16% for 4 plates electrodes and 600 L/h flow rate while for the river water was 29% for 4 plates electrodes and 1000 L/h.

Continuous flow aqueous two-phase extraction of betalains in millifluidic channel

Aqueous Two-Phase System (ATPS) has a proven ability for the selective partitioning and purification of bioactives. This work explores the application of ATPS for the continuous flow extraction of bio-active solute (betalains) from an actual crude extract i.e. red beetroot extract. ATPS composed of Polyethylene Glycol (PEG) 6000 and ammonium sulphate is used for the differential partitioning of betalains and sugars. The continuous flow experiments were performed in millichannel (ID = 1.2 mm) with T-junction. The effect of residence time, multiphase hydrodynamics, and flow-rate ratios on the extraction performance in the continuous flow is studied. The effectiveness of the continuous flow extraction is compared with batch mode extraction of betalains. The continuous flow extraction offers 72.01 % extraction and 89.27 % equilibrium extraction efficiency for betalains with a residence time of 3.38 min. In comparison, batch extraction offered lower performance, with 60.35 % extraction and 74.81 % equilibrium extraction efficiency in 5 min. The improved performance for the continuous flow extraction is attributed to the uniform slug flow in the millichannel. Inclusively, this work develops a continuous flow process for the intensification of extraction of bioactives from the crude extracts of natural sources.

Dewatering performance of aerobic granular sludge under centrifugal with different sludge conditioning agent.

The aerobic granular sludge(AGS) technology draw scientific researchers attention, and more and more scientific research focuses on it, due to its superior advantages, such as good settling performance, high biological phase, high toxicity resistance and multiple biological effects. With the rapid development of AGS technology, a considerable amount of residual AGS will be produced, and dehydration is the biggest bottleneck of sludge reduction. This study investigated the dewatering process and method of residual AGS cultured by continuous flow experiment. Experiments were conducted using centrifugal dewatering technology with a dosing scheme to analyze the granular sludge dewatering process, and investigate the release process of EPS component in AGS dewatering. Our results implied the specific resistance of AGS has a very low value ((1.82 ± 0.03) × 109 m/kg) and it was not obvious for the conditioning effect of chemical conditioner on AGS dewatering. However, the moisture content can be reduced to 63.5% after dewatering with the presence of inorganic substances. The addition of drinking water treatment plant sludge (Alum sludge) can improve the efficiency of the dewatering of AGS. A possible dewatering process of AGS dewatering was proposed which was divided into two stages: First, a considerable amount of free water in the sludge was quickly removed under the action of gravity without pressure filtration. Second, the bound water release required cooperation between applying centrifugal or pressing force to grind granular cells and separate protein-like substances with the inorganic matter inside the granular sludge. The possible mechanism of AGS dewatering and hypothesis dewatering process are useful to optimize the AGS dewatering process.

Efficient H2O2 Production and Activation by Air Diffusion Cathode Combined with Ultraviolet for Lake Water Treatment: A Long-Term Evaluation

This study utilizes a natural air diffusion cathode (ADC) and an ultraviolet lamp to construct a UV/H2O2 reactor for the in situ synthesis and activation of H2O2 and evaluates its potential application in practical lake water treatment. The results indicate that the reactor exhibits stable treatment performance during a continuous flow experiment of 80 h. The air diffusion cathode maintains an H2O2 concentration of above 350 mg·L−1 in sodium sulfate electrolyte and shows no decreasing trend. Under the condition of approximately 59% H2O2 utilization, the removal rates of COD and TOC are 37.6% and 40.0%, respectively; the rate of reduction of A254 is 64.3%; while the total bacterial count removal rate reaches 100%. Large organic molecules in surface water are degraded to small organic molecules and mineralized to inorganic minor molecules. It effectively ameliorates the problem of organic pollution of surface water and effectively kills bacteria and improves the microbiological safety of the water body. Therefore, the UV/H2O2 system developed in this study, based on electrochemically produced H2O2, is an effective method for treating micro-polluted surface water.

Catalytic Upgrading of Acetaldehyde to Acetoin Using a Supported N-Heterocyclic Carbene Catalyst.

We report the catalytic synthesis of 3-hydroxy-2-butanon (acetoin) from acetaldehyde as a key step in the synthesis of C4-molecules from ethanol. Facile C-C bond formation at the α-carbon of the C2 building block is achieved using an N-heterocyclic carbene (NHC) catalyst. The immobilization of the catalyst on a Merrifield's peptide resin and its spectroscopic characterisation using solid-state Nuclear Magnetic Resonance (NMR) is described herein. The immobilization of the NHC catalyst allows for process intensification steps and the reported catalytic system was subjected to batch recycling as well as continuous flow experiments. The robustness of the catalytic system was shown over a maximum of 10 h time-on-stream. Overall, high selectivity S>90 % was observed. The observed deactivation of the catalyst with increasing time-on-stream is explained by ex-situ 1H solution-state, as well as 13C and 15N solid-state NMR spectra allowing us to develop a deeper understanding of the underlying decomposition mechanism of the catalyst.

Crystallinity modulation and microenvironment engineering synergistically manipulate ROS generation on Ni single-atom photocatalysts

The microenvironment modulation of metal-based catalysis sites plays a critical role in single-atom photocatalysis, and remains a grand challenge yet. Herein, the single-atom Ni anchored crystalline carbon nitride (Ni/CCN) nanowire arrays are reported. The obtained Ni/CCN nanowire arrays exhibit an impressive photocatalytic activity (>96% degradation of pharmaceuticals and personal care products (PPCPs) in only 5 min) and photocatalytic rate (maximum 0.5941 min−1) with only clean solar energy input. The Ni/CCN catalyst attached on microfiltration membrane in the continuous flow experiments exhibits >90% PPCPs degradation efficiency over 10 h, demonstrating the ultrahigh activity and long-term operation of the Ni/CCN catalysts. The results of electron spin resonance analysis, probe experiment and theoretical calculations demonstrate that the promoted generation of reactive oxygen species (ROS) highly relies on the crystallinity regulation and microenvironment engineering of active metal sites, which are consequently utilized to trigger the rapid degradation of PPCPs. The introduced Ni-N4 moiety disrupts the uniform distribution of delocalized electrons and precisely tunes the electronic distribution of the microenvironment in CCN, providing an electron-rich region coupled with strong electron transfer effect between Ni and adsorbed O, thus optimizing the crucial step for molecular oxygen activation. This work offers a new idea of photocatalysis from theoretical design towards broad applications through the perspective about modulating microenvironment of active metal sites and optimizing intrinsic electronic properties.

Enhanced Chromium (VI) Removal by Micron-Scale Zero-Valent Iron Pretreated with Aluminum Chloride under Aerobic Conditions

Micron-scale zero-valent iron (ZVI)-based material has been applied for hexavalent chromium (Cr(VI)) decontamination in wastewater treatment and groundwater remediation, but the passivation problem has limited its field application. In this study, we combined aluminum chloride solution with ZVI (pcZVI-AlCl3) to enhance Cr(VI) removal behavior under aerobic conditions. The optimal pre-corrosion conditions were found to be 2.5 g/L ZVI, 0.5 mM AlCl3, and a 4 h preconditioning period. Different kinds of techniques were applied to detect the properties of preconditioned ZVI and corrosion products. The 57Fe Mössbauer spectra showed that proportions of ZVI, Fe3O4, and FeOOH in pcZVI-AlCl3 were 49.22%, 34.03%, and 16.76%, respectively. The formation of Al(OH)3 in the corrosion products improved its pHpzc (point of zero charge) for Cr(VI) adsorption. Continuous-flow experiments showed its great potential for Cr(VI) removal in field applications. The ZVI and corrosion products showed a synergistic effect in enhancing electron transfer for Cr(VI) removal. The mechanisms underlying Cr(VI) removal by pcZVI-AlCl3 included adsorption, reduction, and precipitation, and the contribution of adsorption was less. This work provides a new strategy for ZVI pre-corrosion to improve its longevity and enhance Cr(VI) removal.

Dual electron microregion with oxygen vacancy of Fe0.8La/MCM-48 in bridging peracetic acid and ozonation: Taking the pathway of free radical or nonradical generation?

Efficient tetracycline hydrochloride (TCH) degradation and interface reaction mechanism were investigated by constructing nonradical pathways in heterogeneous peracetic acid coupling with ozonation (O3/PAA) process. Ball-milling assisted Fe–La anchoring MCM-48 catalysts with dual electron microregion was designed to trigger 1O2-dominated non-radical for strong immunity to environment interference. Results exhibited that 83.4% degradation efficiency of TCH was achieved by Fe0.8La/MCM-48/O3/PAA system in only 2 min and 94% TCH was degraded in a 12-hour continuous flow experiment. La with oxygen vacancy regulated the local atomic environment and electron structure of Fe sites, which could initiate peracetic acid activation to promote 1O2 production by surface adsorbed atomic oxygen (*Oad) reaction and this process overcame a lower reaction energy barrier than the binding of surface *Oad to O3. This work offers a reasonable interpretation for Fe–La synergy for inducing non-free radical route, which furnishes theoretical support and practical application for heterogeneous O3/PAA.

Peracetic acid-induced nanoengineering of Fe-based metallic glass ribbon in application of efficient drinking water treatment

This study presents a novel approach utilizing Fe-Si-B metallic glass-based advanced oxidation processes (AOPs) with peracetic acid (PAA) exposure to mitigate disinfection by-products (DBPs) formation in drinking water treatment. Under optimal conditions, it achieved a 98.21% removal of natural organic matter (NOM) and an 80.64% reduction in DBPs formation. The efficacy is attributed to the galvanic cell effect induced by nanoflower structures on the ribbon surface, produced via PAA exposure, thereby enhancing degradation efficiency. High-valent iron Fe(IV) was identified as the primary reactive species, showing robust cycling efficiency under near-neutral conditions. Continuous flow experiments and toxicity assessments using luminescent bacteria further validated the method, demonstrating minimal metal leaching (<0.146 mg/L) and reduced biotoxicity with a 37.68% inhibition rate decrease in 24 h. These findings underscore the promising potential of PAA-integrated Fe-based amorphous alloys for comprehensive water disinfection and purification.

Reactive species identification in KCl activated biochar/persulfate system under different pH condition: Theoretical calculation and column experiments

The challenges of remediating polluted water in mine areas are exacerbated by low emission dispersion and long-lasting pollution, particularly the significant fluctuations in pH value. Notably, the treatment of flotation reagent polluted water with variable pH scenarios remains a challenge. In this study, metal-free biochar-based materials (KBBC)/persulfate system was used for flotation reagent contaminated wastewater treatment with a wide pH range. Regarding the intrinsic nature of the biochar-based materials, ball milling enhanced the degree of graphitization, while introducing a hard template of KCl increased the proportion of carbonyl functional groups on their surface, thereby facilitating persulfate activation. Experimental findings revealed that the KBBC/PS system displayed efficient degradation of aniline aerofloat (AAF) as a representative flotation reagent across a wide pH range (pH = 3.6–10.4 with buffer). Investigations on the mechanism indicated that, under acidic and neutral conditions, superoxide radicals and direct electron transfer processes constituted primary pathways for pollutant degradation. Meanwhile, various active species contributed under alkaline conditions with increased involvement of free radicals (•OH and SO4•−) and singlet oxygen. Furthermore, continuous flow experiments were set up to prove the potential applicability of the KBBC/PS process. This study not only deepens the understanding of persulfate activation by metal-free carbon-based materials across a wide pH range but also expands their potential applications in mine-polluted water purification.