Coagulation is widely used in the field of wastewater treatment because of its simple operation，wide range of application and high treatment efficiency.The physicochemical properties of coagulants play a crucial role in determining the effect of water treatment.Among many coagulants，inorganic metal salt coagulants are favored due to their advantages of fast floc settling speed，low dosage and low cost.In this paper，the inorganic metal salt coagulant was divided into traditional inorganic metal salt coagulant，new inorganic metal salt coagulant and composite inorganic metal salt coagulant，their coagulation performance in wastewater treatment was mainly introduced，their advantages were pointing out and the mechanism related to the removal of pollutants was analyzed，aiming to provide theoretical support for the application of inorganic metal salt coagulant.Inorganic metal salt coagulants in the future should be further developed in the direction of green and high efficiency，promoted the integration of more metal elements，and explored the removal effect of emerging pollutants in more depth.At the same time，artificial intelligence could be used to further optimize the preparation process of inorganic metal salt coagulants，and to investigate the effectiveness of the combination with other water treatment technologies.

With the increasing amount of industrial by⁃product gypsum in China，exploring its high⁃value utilization pathways has become a current research hotspot.Calcium sulfate whiskers，as a material with high strength，high toughness，and excellent high⁃temperature resistance，are gradually becoming an important method for utilizing industrial by⁃product gypsum.In recent years，research on modifying asphalt with calcium sulfate whiskers has made significant progress，indicating that calcium sulfate whiskers can significantly improve the high⁃temperature performance，rutting resistance，and aging resistance of asphalt.However，the problem of decreased low⁃temperature performance caused by calcium sulfate whiskers in the asphalt modification process still needs to be addressed.To solve these problems，researchers have begun to explore the synergistic use of calcium sulfate whiskers with other materials（such as SBS polymer，waste oils） or surface modification to enhance their performance in asphalt.Based on a systematic review of the field's research progress，the preparation methods，basic properties，and current application status of calcium sulfate whiskers in modified asphalt were introduced.For the first time，the mechanism of action，modification effects，and synergistic applications with other materials of calcium sulfate whiskers in asphalt modification were systematically summarized.Additionally，it was looked forward to the challenges faced in the application of calcium sulfate whiskers and future research directions.As a sustainable and economically beneficial material，calcium sulfate whiskers were expected to provide a new approach for asphalt modification and promote the green development of road engineering.

The continuous accumulation of fluoride and chloride ions in the desulfurization ionic liquid leads to a decrease in desulfurization efficiency，increased ionic liquid loss，and exacerbated equipment corrosion.Therefore，the effective removal of F^- and Cl^- in desulfurization ionic liquid has significant research implications.Firstly，six anion exchange resins，such as 717，D730，and D301，were preferably selected to examine their effectiveness in removing F^- and Cl^- from the desulfurization ionic liquid.The results showed that the 717 resin had the best F^- and Cl^- removal performance with equilibrium adsorption capacities of 0.020 mg/g and 3.506 mg/g，respectively.Secondly，the 717 resin was modified with chlorine⁃，hydroxide⁃ and sulfate⁃type modifications to investigate the effects of different modifications on the single F^-，Cl^- and SO₄^2- removal performance.The results showed that the hydroxide⁃type resin had the optimal removal performance for single F^-，Cl^- and SO₄^2-，but its equilibrium adsorption capacity for SO₄^2- was much higher than that for F^- and Cl^-.The sulfate⁃type resin was slightly less effective than the hydroxide⁃type for the removal of F^- and Cl^-，but had no adsorption effect on SO₄^2-.On this basis，the effects of different modifications of 717 resin on the removal performance of mixed ions in desulfurization ionic liquid were investigated，and it was found that the sulfate⁃type resin had the best effect on the removal of F^- and Cl^-.Finally，the FT-IR and XPS characterization results showed that the sulfate⁃type resin adsorbed F^- and Cl^- optimally，mainly because the chlorine⁃type and hydroxide⁃type resins were preferentially ion⁃exchanged with SO₄^2-，while the sulfate⁃type resin was ion⁃exchanged with F^- and Cl^-.

The efficient treatment of dye wastewater is one of the urgent environmental problems that need to be addressed.Herein，the adsorption performance and mechanism of UiO-66 towards methyl orange（MO） were investigated systemically.Firstly，UiO-66-M（M represents the synthesized temperatures） were prepared by solvothermal method at 60，80 ℃，and 100 ℃，respectively.The structural and chemical properties of UiO-66-M were systematically characterized through XRD，SEM，FT-IR，and XPS measurements.Among the three UiO-66 materials，UiO-66-60 exhibited a higher specific surface area（1 386.6 m²/g） and larger average pore size（1.7 nm）.Moreover，the increased ligand defects in UiO-66-60 led to a higher surface density of the hydroxyl groups，resulting in a increased point of zero charge（pH_pzc=6.8） than that of UiO-66-80 and UiO-66-100.The adsorption experiments showed that UiO-66-60 achieved an exceptional MO adsorption capacity of 597.1 mg/g under optimized conditions（pH=3.0，adsorbent dosage=0.2 g/L），which was higher than that of the most reported MOF⁃based adsorbents.The adsorption process followed the pseudo⁃second⁃order kinetic model and Freundlich isotherm model，indicating that MO molecules were adsorbed onto UiO-66-60 in multilayer manner.The electrostatic interaction and π-π stacking interaction simultaneously contributed to the MO adsorption by UiO-66-60.The thermodynamic study indicated that the MO adsorption process was spontaneous and exothermic.Owing to the low⁃temperature synthesis advantage and superior adsorption performance，UiO-66-60 could sever as an efficient adsorbent for MO removal from dye wastewater.

Alumina sol is widely used in fields such as petrochemical catalysts，high⁃temperature⁃resistant materials，and lithium⁃battery material modification.To address the issues of corrosive gas release，environmental pollution，and poor stability in traditional alumina sol preparation，acetic acid was employed as the peptizer and a powder dispersion method was utilized to synthesize alumina sol.The effect of acid to Al ratios，acid dissolution temperature，acid dissolution time，and alumina content on sol particle size and Zeta potential were investigated.Single⁃factor experiments revealed that the acid to Al ratios and temperature significantly influenced the sol particle size and Zeta potential.Orthogonal experiments further confirmed that alumina content was the key factor affecting sol stability，with the sol tending to gel when the alumina content reached 20%.Innovatively，a dry gel redispersion method was adopted to prepare high⁃concentration alumina sol.The primary alumina sol was dried into a dry gel to remove free acetic acid and then redispersed in water to obtain the secondary alumina sol.The stability tests demonstrated that the particle size of the primary alumina sol was increased from 32.72 nm to 171.72 nm after 60 days，accompanied by gelation.In contrast，the secondary alumina sol，despite having the same or higher alumina content，exhibited no significant particle size change and retained fluidity after 60 days.This study successfully synthesized high⁃concentration alumina sol with up to 30% alumina content and a stability period exceeding 60 days，resolving the problems of gelation and environmental pollution in traditional alumina sol preparation and lay a foundation for further industrial⁃scale production.

The high⁃entropy strategy was explored by incorporating tetravalent elements through a solid⁃state reaction method to effectively enhance the thermophysical and mechanical properties of aluminosilicate ceramics.Four high⁃entropy aluminosilicate ceramics with different configurational entropies were successfully synthesized：0.25（Y_1/2Yb_1/2）₄Al₂O₉·0.75（Y_1/2Yb_1/2）₂（xMe_1/x ）₂O₇（x=1，2，3，4；Me=Si，Zr，Ti，Ce）.These ceramics were systematically studied including phase composition，microstructure，thermophysical properties，and mechanical properties.The results indicated that the coefficient of thermal expansion（CTE） of the ceramic samples was gradually increased with the increase of configurational entropy.While the thermal conductivity was decreased significantly.Notably，the sample with the highest configurational entropy exhibited a thermal conductivity as low as 0.6 W/（m·℃），whereas its CTE reached 5.27×10⁻⁶ ℃^-1.In terms of mechanical properties，although the elastic modulus was decreased for the increase of entropy，both hardness and fracture toughness were markedly enhanced.Specifically，the fracture toughness achieved 2.2 MPa·m^1/2，and the Vickers hardness was measured at 8.5 GPa.Microstructural characterization revealed that grain refinement was effectively contributed to the improvement of mechanical properties.This study presented a novel approach for tailoring the thermophysical and mechanical properties of aluminosilicate ceramics and verified the significant potential of the high⁃entropy strategy in the domain of advanced ceramic materials.

The adsorption mechanism of water reducer to clay is of great significance in effectively guiding the design of molecular structure of mud⁃inhibiting polycarboxylate superplasticizer（PCE）.Here，we prepared a series of low molecular weight anti⁃mud PCEs by visible light heterogeneous photocatalysis using Co/CeO₂ as catalyst，（NH₄）₂S₂O₈ as initiator，allyl polyoxyethylene ether（APEG-1000），2-acrylamido-2-methylpropanesulfonic acid（AMPS） and sodium vinyl sulfonate（VS） as monomers.The molecular chain contained functional groups such as carboxyl，amine，sulfonic acid，and polyethylene oxide chains，with a number⁃average molecular weight of approximately 1 400 and a weight⁃average molecular weight of approximately 3 800，and a relatively narrow molecular weight distribution.The most suitable synthesis process condition was obtained as follows.The ratio of APEG-1000、AMPS and VS was 1∶0.1∶0.1.The amount of（NH₄）₂S₂O₈ and Co/CeO₂ was 9% and 0.2%，respectively.The reaction temperature was 60 ℃.The reaction time was 4 h.The initial flow of the cement paste was 272 mm，while the flow was 260 mm after adding kaolin without loss in 60 minutes，demonstrating superior dispersion and antimud properties.The systematic characterizations revealed that the excellent antimud performance could be attributed to several factors.On the one hand，the strong interactions were conducived to anchoring adsorption of the PCE by cement and kaolin particles.On the other hand，the main diffraction peak（001） of kaolin was increased by 0.002 9 nm and the layer thickness was reduced by 4.64 nm when PCE was inserted into the interlayers of kaolin.Overall，this adsorption was beneficial to improve the mud resistance and retention of polycarboxylate superplasticizers.

As a clean energy，solar energy has great potential in dealing with energy and environmental problems，but its utilization efficiency is limited due to its instability.The development of high⁃performance phase change material（PCM） composites is of great significance to solar thermal storage technology，which can effectively solve the problem of space⁃time mismatch between solar energy supply and demand.The purpose of this study is to prepare porous PCM with stable morphology，low undercooling and excellent photothermal conversion performance to solve the problem of space⁃time mismatch between solar energy supply and demand.The composite PCMs with porous expanded graphite as carrier material，n-eicosane as stabilizer and sodium acetate trihydrate（SAT） as phase change energy storage medium was prepared by melt mixing process.The results showed that the composite PCMs sample containing 3.3% expanded graphite had excellent performance.Its phase change enthalpy was 266.54 J/g，and the photothermal conversion efficiency was as high as 91.14%.There was almost no leakage at 90 ℃，and the supercooling degree was reduced to 2.50 ℃.It was also found that although EG had a negative effect on the phase change enthalpy，the composite PCMs remained between 225.71 J/g and 268.30 J/g due to the high enthalpy of SAT.In summary，the modification of SAT with EG and n-eicosane could effectively reduce supercooling，improve photothermal conversion efficiency，and provide a feasible solution for efficient storage and utilization of solar energy.

To address the problem of acidic fluorine⁃containing condensate treatment and reuse in the wet phosphoric acid purification process，a combined process of precipitation and membrane separation was studied as the purification and reuse process of acidic fluorine⁃containing condensate.The precipitation process was studied with the influence of precipitant and induced crystallization carrier on the effluent water quality.The membrane separation process was studied with the influence of operating conditions on membrane flux and effluent water quality during ultrafiltration and reverse osmosis，and membrane contamination and cleaning was discussed.Through the experiments，CaCO₃ was identified as the precipitant and calcite as the induced crystallization carrier.The optimal operating conditions of ultrafiltration was determined.The pressure was 0.4 MPa，the cross⁃flow velocity was 1.0 m/s，the inlet water temperature was 30 ℃，the recovery rate was 70%，and the cleaning and regeneration mode was physical and chemical cleaning，and the optimal operating conditions of reverse osmosis was determined，the pressure was 1.5 MPa，the cross⁃flow velocity was 1.5 m/s，the inlet water temperature was 25 ℃，the recovery rate was 85%，and the cleaning and regeneration mode was chemical cleaning.The effect of the combined process on the actual wastewater treatment was examined，and the fluorine content of the treated actual wastewater was lower than 2 mg/L，and the conductivity was lower than 50 μS/cm，which met the requirements of reuse process.The acidic fluorine⁃containing condensate was reused in the wet phosphoric acid purification process after treatment，which reduced the discharge of fluorine⁃containing wastewater and saved the use of demineralized water，and it had good economic benefits and ecological environmental protection value.

Calcium⁃free roasted chromite ore processing residue（COPR） is a typical hazardous industrial waste generated during chromium salt production and poses significant environmental risks.In this study，a mechanochemical approach was proposed based on the “waste⁃to⁃treat⁃waste” concept，using secondary copper slag（SCS） as a reducing agent to achieve the synergistic detoxification of COPR.The aim was to realize both the resource utilization of solid waste and environmentally friendly remediation.The optimal treatment parameters were determined as follows：ball milling speed of 550 r/min，ball⁃to⁃powder ratio of 12.5，milling time of 120 minutes，mass ratio of SCS to COPR of 1∶5，and the dosage of 98% sulfuric acid of 0.12 mL.Under these conditions，the total leaching concentration of Cr in COPR was decreased from 478.16 mg/L to 2.56 mg/L，and Cr（Ⅵ） was decreased from 455.35 mg/L to 0.25 mg/L，meeting the standards specified in the Technical Specification for Chromium Slag Pollution Control（HJ/T 301—2007）.The characterization results revealed that mechanical forces disrupted the crystalline structure and oolitic morphology of COPR，reduced particle size，and increased reactive surface sites，thereby facilitating the release of encapsulated Cr（Ⅵ）.Meanwhile，Fe（Ⅱ） in SCS was activated under acidic conditions and transferred electrons to Cr（Ⅵ），reducing it to Cr（Ⅲ），which subsequently precipitated as stable hydroxide compounds.This study innovatively demonstrated the feasibility of synergistic Cr（Ⅵ） reduction in COPR using SCS，providing technical support and new insights for the green detoxification and resource utilization of COPR.

The concentrated water from the reverse osmosis（RO） process in the dyeing and printing industry is characterized by high organic content，high alkalinity，and complex salt composition.The main inorganic salts in it are a complex system of sodium sulfate（Na₂SO₄），sodium carbonate（Na₂CO₃），and sodium bicarbonate（NaHCO₃）.In response to the current situation where the technology for recovering sodium sulfate was mature but the resource utilization of high⁃value sodium carbonate was insufficient，an integrated process of "ultrafiltration（UF）+advanced oxidation process（AOP） with ozone+nanofiltration（NF）" was innovatively used to focus on the separation and recovery of sodium carbonate from the complex system.The results showed that the "UF+AOP" pretreatment stage achieved a color removal rate of 98.87% and a COD removal rate of 88.91%，effectively ensuring the stable operation of the NF system.After adjusting the pH by adding acid to convert CO₃^2- to HCO₃^-，the NF system，operating at 1.6 MPa，it reached a rejection rate of 93.42% for SO₄^2- and 16.78% for HCO₃^-.By adjusting the pH with alkali to convert HCO₃^- back to CO₃^2-，the separation of Na₂SO₄ and NaHCO₃ was achieved.The process verification indicated that the entire system operated stably and reliably.This study had established a new method for the selective recovery of valuable inorganic salts from dyeing and printing RO concentrated water，providing a solution with engineering application value for the textile and dyeing industry to achieve zero wastewater discharge and resource recycling，with significant environmental and economic benefits.

In order to improve the adsorption performance and recyclability of molecular sieves，a magnetic molecular sieve with the corresponding structure was prepared by hydrothermal synthesis using coal gangue with a silicon⁃aluminum ratio suitable for X zeolite，and it was used in the treatment of wastewater containing heavy metals.The results showed that the optimal preparation conditions for magnetic X zeolite were：n（H₂C₂O₄）/n（Fe³⁺） was 5，crystallization time was 10 h，and crystallization temperature was 85 ℃，n（citric acid）/n（Al₂O₃） was 0.85，and ultrasound promoted the complexation of molecular sieves and citric acid，which had a better synergistic effect.The synthesized molecular sieves were characterized and analyzed by XRD，SEM，FT-IR，XPS and carbon dioxide adsorption.The effect of parameters such as iron content，adsorption time，pH，initial concentration and amount of molecular sieve added on the adsorption of lead ions were considered.When the iron content of the molecular sieve was 0.33%，the adsorption time was 14 min，the solution pH was 5，the lead ion concentration was 50 mg/L and the molecular sieve dosage was 0.2 g，magnetic X zeolite showed the best adsorption effect on lead ions.Moreover，the magnetic recovery rate of magnetic molecular sieve still reached more than 90% after being recycled 8 times in an external magnetic field，achieving the goal of saving resources，low carbon and environmental protection.

To investigate the effects of different alkanolamine surfactants on the physicochemical properties and microstructure of Ca（OH）₂，as well as its lead adsorption performance，lamellar high specific surface area Ca（OH）₂ were prepared by a digestion method using quicklime as the raw material，triisopropanolamine（TIPA），Diethyl alcohol monoisopropanolamine（DEIPA），and triethanolamine（TEA） as the modifying agents respectively，for the treatment of lead⁃containing wastewater.The Ca（OH）₂ was characterized using X⁃ray diffraction（XRD），high⁃vacuum gas adsorption analyzer，laser particle size analyzer，and field emission scanning electron microscope（FESEM）.The results showed that the lamellar Ca（OH）₂ obtained by using TEA had optimal properties，with specific surface area，pore volume and average pore size of 53.94 m²/g，0.208 cm³/g and 11.66 nm，respectively.A possible formation mechanism for the high specific surface area Ca（OH）₂ was also proposed.Furthermore，The adsorption process for lead in wastewater was well fitted with Langmuir model（R²=0.992 5） and quasi⁃second⁃order kinetic model（R²=0.999 7），indicating that the adsorption process was mainly a single molecular adsorption process based on chemical adsorption，accompanied by physical adsorption，so that the removal efficiency reached 99.54%，and the residual concentration of lead in water was less than 0.46 mg/L，which was far below the discharge limit.These findings demonstrated the broad application prospects of alkanolamine⁃modified Ca（OH）₂ in the treatment of lead⁃containing wastewater.

The residual flotation reagent octadecylamine（ODA） after potassium fertilizer flotation is directly discharged into the environment with the tailings，which has adverse effects on the stability of the ecosystem in salt lake areas and the high⁃value utilization of downstream high⁃value chemicals.To address this issue，the plasma assisted TiO₂ photocatalytic technology was employed to investigate the degradation of ODA aqueous solution.Using the concentration of amine groups in ODA as an evaluation index，the effect of input power，catalyst dosage，and synergistic effect of plasma and photocatalysis on degradation efficiency were investigated through experiments.The changes in O₃，H₂O₂，and ·OH concentrations during the degradation process were studied，and the free radicals generated during the degradation process were detected to elucidate their synergistic degradation mechanism.The experimental results showed that for an ODA solution with an initial concentration of 30 mg/L，the synergistic degradation efficiency was highest when the input power was set to 25 W and the TiO₂ dosage was 17 mg，and complete degradation of ODA could be achieved within 12 minutes.Compared with single photocatalysis and plasma catalysis degradation，plasma assisted photocatalysis technology could significantly accelerate the degradation rate of octadecylamine.The synergistic plasma⁃photocatalytic degradation technology demonstrated exceptional efficiency in ODA decomposition，thereby facilitating the diversified，refined，and high⁃value utilization of salt lake resources.

To enhance the resistance of catalytic cracking catalysts to iron contamination，a metal⁃trapping additive named CatClean was developed using magnesium oxide（MgO），activated alumina（Al₂O₃），and lanthanum nitrate［La（NO₃）₃］ as raw materials via a spray drying method.The resulting CatClean was primarily consist of 60% MgO and 30% La₂O₃，with a wear index of 1.3%/h.Iron contamination was introduced through an impregnation method，and the effects of CatClean on catalyst performance were systematically investigated using XRD，XPS，NH₃-TPD，H₂-TPR，and EDX-Mapping techniques.The results indicated that iron contamination significantly reduced the surface area of the catalytic cracking catalyst.Under high⁃temperature hydrothermal conditions，La₂O₃ in CatClean reacted with iron to form a stable LaFeO₃ phase，effectively mitigating the adverse effects of iron：No formation of MgFe₂O₄ was detected.EDX-Mapping further revealed that iron species could migrate between catalyst and CatClean particles and be effectively captured.Performance evaluations demonstrated that at an iron contamination level of 1.0%，the addition of CatClean reduced the coke yield by 0.78%~0.98%，the dry gas yield by 0.30%~0.33%，and increased the total liquid yield by 0.91%~0.95%，without significantly affecting conversion.These findings confirmed that CatClean significantly reduced the selectivity toward undesired by⁃products and enhanced the catalyst′s resistance to iron contamination.