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Large amounts of xanthate wastewater generated from mineral beneficiation significantly threaten the ecological environment. MOF photocatalysis is considered as a promising method for the removal of xanthate that is environmentally friendly and has high efficiency. However, the defects in MOFs limit their large-scale application due to poor visible light absorption efficiency and stability in water. In this study, a novel composite material composed of g-C 3 N 4 /AgCl/Ti-MOFs was prepared, and the catalytic degradation effect of butyl xanthate solution under different catalyst ratios and reaction conditions was investigated. The results showed that the composite could still maintain excellent catalytic performance (degradation rate of 99.5% within 90 min) under xenon light and low dosage. The characterization results showed that this excellent photocatalytic performance could be attributed to the following three points: 1) The material could absorb up to 670 nm visible light absorption capacity; 2) excellent stability was achieved (86% degradation efficiency after six cycles); and 3) the Schottky junctions formed by Ag0 and other materials in the composite increased the transfer rate of e−/h+. The possible photodegradation mechanism was proposed according to UV–vis DRS and trapping experiments. [ABSTRACT FROM AUTHOR]

The hygroscopicity of expanded vermiculite is one of major influence factors for thermal insulating performance. To explore the water absorption properties of expanded vermiculite prepared via electrical heating method, heating temperature effect on the hygroscopicity of expanded vermiculite was investigated under various humidity circumstances. The influencing mechanisms were analyzed by means of Thermogravimetric Analysis-Differential Scanning Calorimeter technique (TG-DSC), Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and the Brunauer–Emmett–Teller technique (BET) for the measurement of the specific surface area. The results of water absorption experiments indicated that the hygroscopicity of vermiculite showed an inversely proportional relationship to heating temperature and the water absorption content of EV-900 was only 6.206 mg/g with a dramatic decline of 91.5% in comparison with that of RV. This decline of water absorption capacity was mainly attributed to the decrease of interlamellar spacing and specific surface area. In addition, environment humidity had a significant effect on water absorption capacity and velocity. The water absorption content of EV-400 sample increased dramatically from 48.414 mg/g at the humidity of 55%–72.929 mg/g at the humidity of 95%, and the equilibrium time reduced from 3 h to 0.5 h. This study will provide a new perspective and theoretical guidance for the development of vermiculite based thermal insulating materials. [ABSTRACT FROM AUTHOR]

Cable-supported bridges are prone to fire hazards, and the corrosion within further compromises their structural integrity. The present study provides a novel framework for assessing fire-corrosion damage of steel wires currently in use. The relations and failure modes of steel wires under coupled effects of fire-corrosion are established by conducting the tensile test utilizing the replaced steel wires after the fire. Experimental studies found that the deterioration tendency of in-service steel wires after the fire is consistent with that of intact ones, while the corrosion level and position of steel wire have a significant impact on its ultimate strain. To predict the residual mechanical properties of cables after the fire-corrosion coupled damage, a comprehensive database of steel wires properties after the fire is established, and then a data-driven surrogate model is proposed. Finally, four grades are suggested to evaluate various damage degrees of in-service cables under corrosion and fire. The findings can provide bridge owners with guidance on how to replace or repair the damaged components after accidents or natural disaster, thereby increasing the reliability and lifespan of bridges and decreasing the costs associated with maintenance, reconstruction, and replacement. • An assessment approach is proposed to evaluate damaged steel wire of in-service bridge under effects of corrosion and fire. • The relations of replaced steel wires under fire-corrosion coupled effects are established by tensile tests. • A surrogate model and database are developed to predict the response of damaged steel wires accurately and rapidly. • Four grades are suggested to assess various damage degrees of in-service cable under coupled effects fire-corrosion. [ABSTRACT FROM AUTHOR]

The thermal insulating performance of expanded vermiculite is closely related to expansibility. A novel method of Mg2+ modification was proposed to improve the vermiculite expansion ratio. The modification process was characterised by energy dispersive X-Ray spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric-differential scanning calorimeter and scanning electron microscopy. Moreover, the thermal expansion experiment was performed to investigate the expansion behaviours of Raw-V and Mg–V samples at various temperatures. The result indicated that the introduction of Mg2+ could increase the vermiculite interlayer water content through hydration interaction, and the expansion ratio increased 13.7% under the heating temperature of 900 °C after modification. To explain the interaction of magnesium ion and water molecules, a molecular dynamics model was developed, and the simulation results were validated using the binding energy calculation. The results of this study can provide a new perspective and theoretical guidance for the commercial process of vermiculite expansion. [ABSTRACT FROM AUTHOR]

Cr(VI), a common wastewater pollutant discharged from metallurgical, electroplating and other industries poses a threat to human health and the ecological environment. Layered double hydroxides (LDHs), which have a strong anion exchange capacity and memory effect, are excellent adsorbents that are widely used for heavy metal adsorption. In this study, we found that Mg-Al-Fe ternary metal oxides (MAF-LDOs) obtained by the calcination of Mg-Al-Fe hydrotalcite-like compounds (MAF-LDHs) had great potential for the treatment of Cr(VI)-containing wastewater. The influences of the adsorption time, Cr(VI) concentrations, pH value and coexisting metal ions were also considered. By using batch adsorption experiments and various characterization tools, it was found that the mechanism of Cr(VI) adsorbed by MAF-LDO involved the use of a memory effect that involved HCrO 4 - in the reconstruction of laminates. In addition, some laminate -OH groups were protonated to electrostatically attract HCrO 4 -. The -OH groups in the laminate acted as electron donors to reduce Cr(VI) to Cr(III) that then underwent complexation for the effective removal of Cr(VI). The maximum theoretical adsorption capacity of MAF/LDOs for Cr(VI) was 122.85 mg/g at 20 °C. Furthermore, the MAF-LDO demonstrated excellent stability and reusability. In conclusion, the MAF-LDO exhibited a simple synthesis process, superior adsorption capacity with a short contact time, and a wide pH range of application. Hence, it is well-suited for industrial wastewater treatment and provides new insights for treating Cr(VI)-containing wastewater. [Display omitted] • A specific ratio of Mg-Al-Fe was selected to synthesize MgAlFe-LDHs. • MgAlFe-LDHs was modified by calcination. • MgAlFe-LDOs exhibited excellent removal ability for Cr(Ⅵ) and was suitable for treating acid industrial wastewater. • Simple synthesis and low cost. [ABSTRACT FROM AUTHOR]

We present results of density functional theory (DFT) study on the mechanism of photo-organocatalytic β-functionalization of aldehydes with Michael acceptors. The plausible mechanism afforded involves three distinct steps: radical generation, radical addition, oxidative hydrogen atom transfer. The region-determining step is the radical addition step which affords α- or β-radical addition adduct through α-/β-transition states with different barrier. In the reduction step of radical addition adduct, the calculation results support our proposal that oxidative hydrogen atom transfers (HAT) from enamine to the radical addition adduct, generates a neutral intermediate and β-enaminylradical, the latter of which thereafter participates in the previous step of radical addition to form β- intermediate. Our result is in satisfactory accordance with the experimental observation. [ABSTRACT FROM AUTHOR]

Aimed to solve the problems of low adsorption capacity, complex preparation and difficult recovery for reported cesium ion adsorbents, a novel high-efficiency Cs+ adsorbent of vermiculite/zinc hexacyanoferrate (II) (VMT/ZnHCF) composite was prepared via in situ synthetic method. The structure and properties of this composite were comprehensively characterized using XRD, FTIR, SEM, TEM, and TG-DTA. The maximum Cs+ adsorption capacity was recorded to be 378.79 mg/g, and this value was significantly higher than the values recorded for other absorbents. This spontaneous and exothermic adsorption behavior could be explained by the Langmuir isotherm model and the pseudo-second-order kinetic model. In addition, this composite exhibited excellent selective adsorption ability towards Cs+ even in solutions containing high concentrations of Na+, K+, Ca2+, and Mg2+. The Cs+ adsorption mechanism was analyzed by conducting ion exchange experiments and using XRD, SEM, and XPS techniques. The Cs+ adsorption of the VMT/ZnHCF composite was synergistically achieved through the ion exchange of Na+ in vermiculite interlayers and Zn2+ in zinc hexacyanoferrate (II) lattices. A high-efficiency and simple preparation of cesium ion adsorbent has been developed in application of cesium ion wastewater treatment. This work can provide theoretical guidance to realize the non-hazardous treatment of radioactive wastewater. [Display omitted] • A novel high-efficiency Cs (I) adsorbent of VMT/ZnHCF was prepared via an in situ synthetic method. • VMT/ZnHCF obtained a maximum Cs (I) adsorption capacity of 378.79 mg/g significantly superior to other absorbents. • VMT/ZnHCF exhibited excellent selective adsorption ability towards Cs (I) in multicomponent metal ion solutions. • Cs (I) adsorption behavior is ascribed to synergistic ion exchange of Na+ and Zn2+ in VMT/ZnHCF. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel expanded vermiculite/xonotlite insulation composite was prepared via the hydrothermal method. • Vermiculite thermal expansion and nano xonotlite fiber synthesis were comprehensively studied. • The effect of intercalation on thermal insulating performance was systematically investigated. Natural disasters caused by global warming are threatening the survival of mankind. Reducing carbon emissions is an effective way to prevent global warming. In recent years, the construction industry is playing a dominant role in global energy consumption. Aimed to solve the problem of high energy consumption in the construction industry, a novel expanded vermiculite/xonotlite thermal insulation composite was successfully prepared via the hydrothermal method. The microstructure and thermal performance of the composite were systematically analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), laser flash analysis (LFA), and infrared thermal imaging. The test results indicated that xonotlite fibers could be inserted well into the interlayers of expanded vermiculite. And the intercalation of xonotlite greatly improved the thermal insulation performance of expanded vermiculite at high temperature. The thermal conductivity of this composite decreased with intercalation rate increasing. The composite with intercalation rate of 51.43 % had the lowest thermal conductivity of 0.2116 W/mK at 800 °C which was 55.36 % lower than the expanded vermiculite sample. Meanwhile, this composite had good thermal stability and high temperature resistance. In addition, the thermal expansion of vermiculite and the synthesis of nano-xonotlite fibers were comprehensively studied and discussed. This study will provide a new perspective and ideas for developing vermiculite-based thermal insulating materials. [ABSTRACT FROM AUTHOR]

Spinel-type lithium titanate (Li 4 Ti 5 O 12 ) attracts increasing attention for large-scale energy storage as a promising alternative to the graphite in view of superior safety and stability. Nevertheless, the main challenge of Li 4 Ti 5 O 12 anode is the poor electronic conductivity which restricts its battery performance. Herein, the Ce-doped Li 4 Ti 5 O 12 /C embedded in multiwalled carbon nanotube (MWCNTs) network is successfully fabricated through a conventional sol-gel method. The doped Ce 3+ -ion and the formed conductive network between the coated carbon and MWCNTs are favorable to improve the kinetics of Li 4 Ti 5 O 12 toward fast electron transport and Li + -ions diffusion. Such a unique hybrid exhibits superior high-rate and long cycle-life performances when used as an anode material for lithium-ion batteries. It delivers specific capacities of 171.5 and 145.3 mA h g −1 at 0.2 and 10 C between 1.0 and 2.5 V, respectively, and reversible capacity of 129.3 mA h g −1 after 600 cycles at high rate of 20 C with capacity retention of 98.6%. Moreover, the EIS results reveal that this anode material exhibits high electronic conductivity and fast Li + -ions diffusion. This study provides a new stragety to prepare other electrode materials for high-performance energy storage device. [ABSTRACT FROM AUTHOR]

• This study proposed the surrogate model to predict recycled aggregate concrete (RAC) creep behavior utilizing machine learning (ML). • Both grid search algorithm and k-fold cross-validation were utilized to find the optimal hyperparameters. • The XGBoost, was shown to have a higher efficiency and accuracy for predicting RAC creep over other methods. • The results are helpful to comprehend the performance of RAC structures and promote the application of RAC in buildings. This paper comprehensively investigated the surrogate model of recycled aggregate concrete (RAC) creep behavior prediction for the first time utilizing five typical machine learning (ML) algorithms trained with the RAC_Creep_v1 database. The grid search algorithm and k -fold cross-validation are performed to find the optimal hyperparameters. Then, attribute importance analysis and correlation analysis were conducted to evaluate the effect of various input variables on the results. By retraining the XGBoost model after feature selection, the results revealed that loading age has the greatest impact on RAC creep performance. The XGBoost, the optimal model via evaluation and comparison, was shown to have a higher efficiency and accuracy for predicting RAC creep subjected to different variables. Furthermore, the result of this paper can assist designers in comprehending the performance of RAC structures, promoting the application of RAC in buildings and the study for reducing carbon emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel humidity self-regulating interior wall coating composite based on red mud was prepared. • The hygroscopicity of HRCRM were systematically investigated and analyzed. • Various properties of HRCRM were tested and the moisture absorption mechanism was analyzed. Aimed to resolve the problem of excessively high indoor humidity in subtropical areas and develop a new resource disposal technique for red mud, a novel humidity self-regulating interior wall coating composite based on red mud (HRCRM) was successfully prepared using red mud as a matrix material and vermiculite as a humidity regulator. The effects of component proportion, ambient humidity, exposure time on hygroscopicity of this composite were systematically investigated. This composite exhibited good humidity regulating ability with the largest water absorption rate of 16.38% under experimental conditions. Moreover, various properties were tested including surface drying time, hardness, adhesion, coating appearance, water resistance and reusability, meeting the national standard requirements well. The mechanism was comprehensively analyzed by XRD, TG-DTG, FESEM, and FTIR, indicating that the humidity self-adjusting function of HRCRM was realized by regulating the interlayer water storage of vermiculite. This study can provide theoretical and technical guidance for residential environment improvement in subtropical areas and comprehensive utilization of red mud. [ABSTRACT FROM AUTHOR]

• A machine learning framework is developed to predict the cable damage under coupling effects of corrosion and fire. • LS-SVM method is utilized to establish surrogate model for cable damage detection. • Effect of material uncertainties on cable damage prediction analysis are considered. • The proposed computational framework can be utilized in cable damage identification and time-dependent analysis. This paper proposes a novel machine learning-based cable damage detection model to investigate the upper and lower bounds of bridges' cable damage degrees under the effects of corrosion and fire. In the proposed approach, the surrogate model for bridge cable damage detection under stochastic effects of corrosion and fire was established by combining machine learning and finite-element analysis to estimate the remaining life of cables. Then the accuracy and generalization performance of three typical machine learning methods for cable damage prediction are compared, such as Back Propagation neural network(BPNN), Radial Basis Function neural network(RBFNN) and Least Square-Support Vector Machine (LS-SVM). It is conducted that LS-SVM owns better prediction accuracy for cable damage under the coupling effects of corrosion and fire than the others. Additionally, the LS-SVM surrogate model combined with stochastic analysis and time-dependent deterioration model of steel wires under corrosion and fire is used to obtain the upper and lower bounds of cable damage under coupling effect of corrosion and fire. The proposed surrogate model can assist management in diagnosing and evaluating cable damage more quickly, efficiently, and flexibly once the real-time monitoring data is obtained. In addition, the surrogate model can guide bridge maintenance in advance. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated thermal stability of fumed silica based thermal insulating composites prepared by dry molding technology. The results showed that the composites could keep excellent thermal stability at the temperatures below 800°C. However, when the samples were used at higher temperatures (>800°C), the volume shrinkage increased sharply, which directly led to a serious deformation and then affected thermal insulating properties in applications. The utilization of fumed alumina could significantly improve thermal stability of the composites. When 5wt.% fumed alumina was added, the volume shrinkage decreased from 10.49% to 3.47% at 1000°C. The desirable results would be achieved by adjusting the amount of fumed alumina according to practical using temperature. In addition, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were employed to characterize the microstructure and phase transformations of the composites treated at different temperatures. [Copyright &y& Elsevier]

Microwave-assisted pyrolysis of Chlorella vulgaris was carried out under compound additives, which contained catalyst (ZSM-5) and microwave absorbent (graphite). The effects of three independent variables (Si/Al ratio of ZSM-5, additives amount and catalyst ratio) on the weight loss characteristics, product yield and energy consumption were investigated. Response Surface Methodology (RSM) coupled with Box-Behnken Design (BBD) was used to optimize pyrolysis time (T s) and bio-oil yield (B o) of Chlorella vulgaris pyrolysis under three independent variables. The results showed that compound additives can promoted the pyrolysis progress and increased the bio-oil yield. Besides, compound additives can also reduce the energy consumption of bio-oil production in most cases. The predicted results showed that optimal T s and B o were 3550s and 22.70%, respectively. GC-MS analysis further revealed that compound additive has stronger effect on denitrogenating than single additive, which is of great significance in alleviating nitrogen oxide pollution caused by bio-oil with high nitrogen content. [Display omitted] • The efficiency of pyrolysis is obviously improved by the addition of ZSM-5 and graphite. • Compound additives can save 558.87 kJ energy for each 1 g of bio-oil. • Influencing factors to bio-oil yield were ordered as: Si/Al ratio > catalyst ratio > additive amount. • Bio-oil yield is optimized by RSM and obtained is 1.27 times than original. • Compound additive has better denitrification effect of bio-oil. [ABSTRACT FROM AUTHOR]

Developing nanoporous thermal insulation materials is an effective method for solving energy consumption problems. In this study, fumed silica based thermal insulating composite was prepared using a novel dry molding method. Thermal conductivity was measured using a guarded hot plate method in the steady state. The results indicated that this composite exhibited excellent thermal insulating performance, achieving an ultra-low thermal conductivity of 0.0205 W/mK at 100 °C. By analyzing the microstructure using field emission scanning electron microscopy (FESEM), we found that the fiber surface was modified by a 12 μm-thick layer of fumed silica particles that reduced solid heat transfer. However, at high temperatures, thermal insulating performance decreased rapidly, and thermal conductivity reached up to 0.119 W/mK at 500 °C. Based on this problem, a heat transfer model was constructed to explain micro-nano scale heat transfer mechanisms of this composite. The results indicated that gas-solid coupled thermal conductivity occupied a large proportion of 78.3% at 100 °C, but the value was only 0.015 W/mK. As the serving temperature increased, radiative heat transfer gradually occupied the dominant position in total heat transfer. Radiative thermal conductivity reached up to 0.101 W/mK at 500 °C, which was approximately 93.3% of total thermal conductivity. Therefore, it was apparent that the increase in radiative heat transfer was the main cause of the decline in thermal insulating performance at high temperatures. Additionally, the effect of the fiber mass ratio on thermal conductivity was investigated at various temperatures. Empirical and simulated data were compared, and the results revealed that the heat transfer model was basically consistent with experimental findings, achieving a mean error of only 4.78%. [ABSTRACT FROM AUTHOR]

• Time-dependent nonlinear buckling behaviour of 3D concrete-filled steel tubular (CFST) arch structures considering both random and interval uncertainties were investigated. • Critical nonlinear limit and bifurcation buckling loads were formulated using Chebyshev surrogate model strategy combined with finite element method. • The present method can accurately predict the critical buckling loads and load–displacement paths at any time of the loading age. • The present approach is capable of analysing nonlinear buckling of complex 3D structures with hybrid random interval uncertainties. Limit point and bifurcation buckling loads are critical concerns in structural stability design. With the inevitable viscoelastic effects of creep and shrinkage in concrete, such critical buckling points may vary due to the time-dependent change of equilibrium configuration. Furthermore, the intrinsic uncertainty and natural randomness in the geometry and material characteristics would affect the structural stability performance significantly. The present study provides a new robust method, called the generalized Chebyshev surrogate model-based sampling approach, in assessing the time-dependent nonlinear buckling behaviour of 3D concrete-filled steel tubular (CFST) arch structures when both random and interval uncertainties are involved. In the proposed approach, the relationships between the uncertain parameters and the critical nonlinear limit and bifurcation buckling loads are formulated using Chebyshev surrogate model strategy combined with finite element method. The extreme bounds of the statistical features, including means, standard deviations, of the critical nonlinear buckling loads are furnished by using Monte Carlo method and Quasi Monte Carlo simulation method. Finally, the applicability and the validity of the proposed approach are illustrated with a series of numerical investigations. [ABSTRACT FROM AUTHOR]

The present study aimed to increase the utilization of phosphogypsum and reduce cement consumption. Single-factor experiments were designed to the effects of water-cement ratio (0.45–0.30), silica fume (1 %∼7 %), cement dosage (0 %∼20 %), and the RPG/HPG (20/80–0/100) on mechanical properties of phosphogypsum-based concretes (PGBCs). A new phosphogypsum-based concrete was prepared to meet the compressive strength requirement of C30 grade. The maximum 28d compressive strength of this PGBC reached 45.1 MPa. Simultaneously, the effect mechanisms of above four factors on the mechanical properties of PGBCs were discussed by combining XRD and SEM results. Moreover, the volume stability, elastic parameters, and compressive constitutive model of this PGBC with compressive strength above 30 MPa were investigated. This PGBC used more than 80 % phosphogypsum and 10∼20 % cement, exhibiting well economy and environmental friendliness. Moreover, the constitutive model was established to well predict the compressive behavior of PGBC with different RPG/HPG relative ratios. This PGBC had better volume stability and weaker deformation resistance than cement-based concrete. The present results can provide more theoretical and technical supports for the large utilization of PG. • PGBC is prepared with a large amount of PG as a cementing material. • The effects of four facters on the strength of PGBC were discussed. • The strength formation mechanism of PGBC were discussed by XRD&SEM. • A damage constitutive model with good correlation coefficient was established. • Providing theoretical and technical supports for the efficient utilization of PG. [ABSTRACT FROM AUTHOR]

Spent potliner (SPL) has been listed as a hazardous waste derived from aluminum electrolysis production with high cyanide content. In this study, a novel microwave-sensitizer synergistic technique was proposed to rapidly remove cyanides in SPL. The occurrence states and removal behavior of cyanide in SPL were studied systematically. The results show that cyanide in SPL mainly exists in the form of sodium cyanide and ferricyanide. The maximum cyanide removal rate of 96.67% was successfully achieved under the experimental conditions. Meanwhile, the synergistic removal mechanisms were comprehensively investigated by XRD, XRF, TG-DTA, TG-MS, and FactSage thermal simulation software. The sensitizer Fe 2 O 3 can accelerate the decyanation reaction by decreasing activation energy and acting as an oxidant. This study not only develops a high-efficiency and rapid cyanide removal technique, but also provides theoretical guidance for non-hazardous treatment of other cyanogens-containing wastes. [Display omitted] [ABSTRACT FROM AUTHOR]

Grey fixed weight clustering (GFWC) method is studied to predict the slagging tendency of biomass fuels combustion. Then the results of the GFWC method were verified and compared with experimental results. In the experiment, bagasse was chosen as an example to prepare ash from three different pretreatment groups (non-washing (NW), water-washing (WW), acid-washing (AW)) and two samples adding kaolin and calcite respectively. The degree of slagging was determined by measuring the ash melting point temperature with the ash melting point analyzer and observing the structural morphology of the particles by the scanning electron microscope (SEM). The GFWC method was used to synthesize the five single slagging prediction indexes, and a mathematical model for the evaluation of slagging was proposed to improve the accuracy of the evaluation results. Furthermore, the accuracy and applicability of the GFWC method for the estimation of slagging tendency of 25 kinds of biomass were tested. Compared with SI method and ternary equilibrium phase diagram, the estimation of GFWC method can avoid the uncertainty and it agreed with the SEM characteristics and ash fusibility temperatures (AFT). This study provides a new reference for biofuel slagging trend estimation based on ash composition. [Display omitted] • The GFWC model was proposed to evaluate the slagging tendency. • The effects of pretreatment and additive on slagging tendency were compared. • The accuracy of the algorithm was verified through experiments. • The other 25 biomass slagging tendencies were estimated by GFWCM. • Compared with SI and SCK system diagram, GFWCM can avoid the uncertainty. [ABSTRACT FROM AUTHOR]

In this study, a sugarcane bagasse biochar/nano-iron oxide composite was prepared via a one-pot pyrolysis method by using the sugarcane bagasse-based solid waste and microwave as the raw material and energy source, respectively. The developed composite was characterized by BET, XRD, FT-IR and TEM and was applied for the removal of Cr (VI) from water. The composite was observed to be mainly composed of amorphous carbon, Fe 3 O 4 and Fe 2 O 3. The iron oxides were uniformly embedded on the surface of the carbon layer by van der Waals force. The sugarcane bagasse-based biochar/nano-iron oxide composite material exhibited an optimal Cr (VI) adsorption capacity of 55 mg/g under the experimental conditions specified in this study. The Cr (VI) adsorption mechanism of the Fe 2 O 3 /Fe 3 O 4 /WBC composite was explained through FTIR, XPS, charge transfer analyses, and density functional theory calculations (DFT). The deposition of Cr (VI) on the surface of the composite was attributed to electrostatic interaction, redox reactions and complexation between the Fe 2 O 3 /Fe 3 O 4 /WBC composite and Cr (VI) contained in the solution. [Display omitted] • A sugarcane bagasse-based biochar/nano-iron oxide composite was prepared via a one-pot pyrolysis method. • This composite features a more uniform distribution of iron oxides and a significantly improved Cr (VI) adsorption capacity. • The Cr (VI) adsorption of this composite is attributed to electrostatic interaction, complexation and redox reactions. [ABSTRACT FROM AUTHOR]

Bentonite is an important clay for preparation of adsorbents for potential treatment of industrial effluents. However, due to its natural occurrence as fine particles and swelling after moisture absorption, bentonite is difficult to be separated from the liquid for regeneration purpose, which limits its application in effluent treatment. In this study, two different bentonite-polypropylene composites were synthesized, i.e., with and without pore-enlarging treatment. They both showed strong ability to resist hydraulic agitation damage with a small breakage rate in water. The obtained results from SEM and XRD characterization revealed that the compounding of bentonite with the polypropylene was a physical process, and the structural characteristics of bentonite particles were maintained in the new products. The granular composite adsorbents were effective in removing Pb 2+ in aqueous solution. The suggested pore-enlarging treatment was verified as a successful operation to increase greatly the adsorption rate of contaminants on the granular bentonite composite. [ABSTRACT FROM AUTHOR]