Zhaoru Fan,Shouyong Zhou,Ailian Xue,Meisheng Li,Yan Zhang,Yijiang Zhao,Weihong Xing

1 Jiangsu Engineering Laboratory for Environmental Functional Materials,Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials,School of Chemistry and Chemical Engineering,Huaiyin Normal University,Huai'an 223300,China

2 State Key Laboratory of Materials-Oriented Chemical Engineering,Nanjing Tech University,Nanjing 210009,China

Keywords:Low-grade palygorskite clay Porous ceramic support SiC Sintering

ABSTRACT A low-cost porous ceramic support was prepared from low-grade palygorskite clay(LPGS)and silicon carbide(SiC)with vanadium pentoxide(V2 O5 )additives by a dry-press forming method and sintering.The effects of SiC–LPGS ratio,pressing pressure,carbon powder pore-forming agent and V2 O5 sintering additives on the microstructure and performance of the supports were investigated.The addition of an appropriate amount of SiC to the LPGS can prevent excessive shrinkage of the support during sintering,and increase the mechanical strength and open porosity of the supports.The presence of SiC(34.4%)led to increases in the open porosity and mechanical strength of 40.43%±0.21%and(17.76±0.51)MPa,respectively,after sintering at 700°C for 3 h.Because of its low melting point,V2 O5 can melt to liquid during sintering,which increases the mechanical strength of the supports and retains the porosity.Certainly,this can also encourage efficient use of the LPGS and avoid wasting resources.

1.Introduction

Membrane separation technology can effectively solve common problems in many fields,and membrane materials are the foundation of membrane separation technology[1,2].The key to promote larger scale and wider application of membrane separation technology is to develop membrane materials with a higher performance,stronger pollutant inhibition and easier cleaning[3].As a new type of ceramic material,the porous ceramic support has a large number of pore structures with a porosity of 20%–97%,with many advantages,including[4–6]:(1)a high mechanical strength;(2)a high porosity;and(3)a good thermal and chemical stability.

The porous ceramic support is composed mainly of metal oxide as aggregate,and is produced by additive introduction with dry pressing,extrusion,flow casting or other methods and sintering at a high temperature.Chang et al.used alumina as an aggregate to prepare flake ceramic supports by dry pressing,and sintering at 1450°C and 1510°C to obtain an alumina support with a mechanical strength of 77 MPa and 153 MPa respectively[7].However,because of the special properties of the metal oxide powder,the raw material price is high and it is difficult to be sintered.Therefore,many researchers are looking for high-performance,low-cost materials to replace metal oxides,and some progress has been made.Zhu et al.used mullite whiskers as an aggregate to prepare porous ceramic supports.After sintering at 1200°C,the mechanical strength of the support reached 80 MPa,with a high porosity and permeability[8].Zhu et al.used recycled industrial waste fly ash and bauxite as raw materials,and prepared a porous ceramic membrane support at a sintering temperature of 1100–1400 °C.The results showed that when the sintering temperature was 1200°C,the porosity of the support reached 46%and the mechanical strength was 80 MPa[9].It can be fined that the cost of the raw material and support preparation was reduced significantly,and the performance remained unchanged.Therefore,the preparation of porous ceramic supports with clay minerals as aggregate is a viable option.

Palygorskite has unique nanorod crystals,porous structures and abundant hydroxyl groups [10],which enable palygorskite to construct nanocomposite materials through rod crystal and surface groups,and to construct hybrid functional materials through nanopore channels.Our research group successfully prepared a palygorskite nanofiber separation layer on a tubular alumina support by dip-coating [11].The average pore diameter of the membrane layer was 0.250 μm,the thickness was 6.7 μm,the permeability reached 1540 L·m?2·h?1·bar?1(1 bar=105Pa),and the membrane layer had no obvious defects,thus the preparation cost was reduced.Simultaneously,the membrane layer had an obvious interception effect on the calcium carbonate suspension,a stable permeation flux and no obvious damage to the membrane after backwashing regeneration.Palygorskite has been used in the field of organic membranes to improve corrosion resistance (Polyvinylidene Fluoride (PVDF) ultrafiltration membrane) [12–14].The addition of palygorskite could improve the tensile strength of the PVDF ultrafiltration membrane significantly,and improve the membrane permeability when the selectivity of the membrane remained almost unchanged.When 10 wt% palygorskite was added,the wear resistance of the membrane was improved significantly,the wear rate decreased to 1/170 of the original membrane,and the permeability flux increased from 106.1 L·m?2·h?1to 282.5 L·m?2·h?1.In addition,palygorskite was also used in other fields,such as catalysts[15],adsorbents[16],etc.

However,palygorskite purification is problematic [17].In terms of main mineral groups,Xuyi palygorskite clay can be divided into five main categories:(1) palygorskite clay;(2) montmorillonite–palygorskite clay;(3) dolomite–palygorskite clay;(4) opalite–palygorskite clay;and(5)montmorillonite clay.The higher the grade of palygorskite clay ore,the simpler the purification process and the lower the treatment cost.Therefore,high-grade palygorskite clay ore has been developed and used effectively[18,19],low-grade palygorskite clay ore(LPGS)has been mostly discarded because of its low palygorskite content,which has restricted the development of the palygorskite clay industry.So,the rational and efficient use of a LPGS is required urgently for the green development of the palygorskite industry.

LPGS can meet the conditions for preparing high-performance supports due to its advantages of a low sintering temperature,rich sources,a good plasticity and etching [19].The development of membrane materials with an excellent performance can achieve the efficient utilization of LPGS clay and provide guidance for the development of lowcost membrane materials.However,palygorskite clay contains free water,bound water and a large number of surface hydroxyl groups,which makes it easy to shrink during sintering[20,21].Due to the silicon carbide(SiC)has a stable chemical property,a high thermal conductivity,a small thermal expansion coefficient,a good wear resistance and a low cost [22,23].Simultaneously,SiC supports are one of the most promising membrane materials for gas filtration[22–24],water treatment[25,26]and gas separation[27].Compared with other oxide materials,SiC ceramic membranes exhibit an excellent chemical stability,and so can be used for separations under harsh conditions,such as corrosive liquid or hot gas environments[28,29].Therefore,SiC is introduced into the support by conventional powder mixing to prepare the LPGS support and prevent shrinkage of supports during sintering.

Hence,to achieve the effective use of low-grade palygorskite clay,a low-cost porous ceramic support was prepared from a low-grade palygorskite clay and SiC with V2O5additives by dry-press forming and in-situ sintering.The phase composition,microstructure and thermogravimetry-differential scanning calorimetry(TG-DSC)of the LPGS and support mud were investigated.Furthermore,the open porosity,mechanical strength and average pore size of the supports were also investigated.Finally,the sintering temperature and holding time were studied.

2.Experimental

2.1.Materials

Low-grade palygorskite clay(～17 μm,Xuyi OBT Co.,Jiangsu,China)was used as an aggregate.Commercial SiC powders (～10 μm,Yuda Corundum Co.,Nantong,China)were used as additives.The activated carbon powder (～12 μm,Ansheng Fine Chemical Technology Co.,Guangdong,China) was added as a pore-forming agent.Vanadium pentoxide(V2O5)and polyvinyl alcohol(PVA)(analytical purity,Shanghai Aladdin Biochemical Technology Co.,Ltd.,Shanghai,China)were used as a sintering additive and binder.

2.2.Fabrication of supports

The sample compositions are presented in Table 1.After mixing well with mechanical stirring,the PVA solution(8 wt%)was added to thepowder mixture for a further 1 h of grinding.The obtained mud was pressed into a round sheet (30 mm diameter × 3 mm length) and a strip (50 mm × 5 mm × 4 mm) supports at 10 MPa in a self-made metal mold.

Table 1 Mixing ratio and sample designation of starting mixtures

All the supports were dried for 12 h at 70°C and 110°C in an oven respectively and sintered for 3 h at 650–700°C in air atmosphere.For 700°C as an example:the temperature was increased to 700°C from room temperature at 1°C·min?1,kept at 700°C for 3 h,and then the temperature was lowered at 2°C·min?1.When the furnace temperature was below 250°C,the muffle furnace was closed[16].

2.3.Characterization

Thermogravimetric analysis of the LPGS and premixed powder was conducted at a heating rate of 10°C·min?1from 10 to 800°C in air by using a thermogravimetric analyzer (TG-DSC STA449F3,Netzsch,Germany).The microstructure of the low-grade palygorskite clay;SiC and supports were observed by using a field emission scanning electron microscope(FESEM,S-4800,Hitachi,Japan).The phase composition was determined by using an X-ray diffractometer (XRD;XTRA,ARL,Switzerland).The open porosity was determined by the Archimedes displacement method with water as the liquid medium by using the following equation[22,29]:

where P is the open porosity,M3is the saturated mass(g)in air,M2is the saturated mass(g)in water and M1is the dry mass(g)in air.

The pore size distribution was measured by using a pore size distribution analyzer (POROMETER 3Gzh,Quantachrome Instruments,America)and the pore size D was calculated from:

where γ is the surface tension of the solvent (dynes·cm?1,1 dyn=10?5N),p is the pressure drop(kPa)through the support,S is the shape factor and θ is the contact angle.

The mechanical strength was measured by a three-point bending test(AGS-X,Shimadzu,Japan)by using the following equation[22,29]:

where σ is the mechanical strength (MPa),F is the maximum force(N)when the cross bar presses on the support,L is the support distance(mm),B is the width(mm),and H is the height(mm).

The gas flow rate of the supports was measured by using a homemade device.The gas permeability coefficient was calculated by using the following equation[30]:where ψ is the gas permeability(m·h?1·kPa?1),ΔP is the pressure drop(kPa),Q is the gas volume through the support per hour(m3·h?1)and A is the area(m2)of the support.

The support shrinkage was measured by using the area value of the membrane before and after thermal treatment by using the following equation[31]:

where η is the shrinkage of the support(%),and S0and S are the area values of the support before and after sintering,respectively.

3.Results and Discussion

3.1.Microstructure and phase composition of materials

The SEM and particle size distribution of the LPGS and SiC are shown in Fig.S1 in supporting information.Fig.S1(A1)shows that the LPGS shape is irregular and a small amount of PGS crystal is visible.The particle size distribution shows that the particle diameter is～17 μm with a wide particle size distribution range(Fig.S1(B1)).

Fig.S1(A2)shows that the SiC is a high purity and free of impurities.The particle size distribution curve is narrow,which also indicates that its particle size is～10 m(Fig.S1(B2)).

The XRD diagram shows that in addition to the PGS,the LPGS also contains SiO2,FeO,CaCO3and other components(Fig.1).

3.2.Sintering behavior of materials

The Thermo Gravimetric Analysis-Differential Scanning Calorimetry(TGA-DSC)curve of the LPGS and premixed powder are given in Fig.2.From Fig.2(A),the TGA curve of LPGS and premixed powders showed the same downward trend.When the sintering temperature reached 700°C,the TGA curves remained unchanged,and the mass of premixed powders was heavier than the LPGS,it can be explained that the premixed powder contains SiC particles,and the state and crystal shape of the SiC remained unchanged at 700°C[21,32],but the crystal shape of LPGS changed and its quality decreased at this temperature.

Fig.2(B)shows that the DSC curve of the LPGS powders has an obvious endothermic peak near 640°C.Combined with the TGA curve,it is found that the mass loss of LPGS powder changes slightly,which indicates that the LPGS powder undergoes an obvious crystal form change at this temperature,which results in an endothermic reaction.The DSC curve of the premixed powders has an obvious endothermic peak at 104.3°C,which is the result of the effect of the conversion of liquid water into water-vapor absorption of heat.The intense exothermic peak near 550°C is attributed to activated carbon powder combustion heat release[29].

Fig.1.XRD analysis of LPGS.

Fig.2.TGA(A)and DSC(B)curves of LPGS and mixture powders measured in air.

3.3.Effects of mass ratio of LPGS/SiC

The photos of unsintered LPGS support and the support sintered at 700 °C for 3 h as shown in Fig.S2.The shrinkage rate was as high as 30%±0.12%,with a low porosity and the mechanical strength of only(3.5 ± 0.5) MPa,which suggests that the support prepared by LPGS alone without SiC had little application value.In addition,it can also be seen from the SEM(Fig.3)that the structure of the supports with SiC remained intact after sintering at 700°C.It can be seen that a large number of pores exist on the surface of the support.However,the surface of the support without SiC forms densification,and the surface is basically free of pores.Therefore,in order to avoid excessive shrinkage of the supports during sintering,SiC powders were added to the LPGS and mixed to prepare the support.

The shrinkage rate after roasting is shown in Fig.4A,which shows that with SiC addition,the shrinkage of the support decreased significantly.When the mass ratio was 2:1(S1),the volume shrinkage rate of the support was only 3.93%±0.16%,and the shrinkage decreased gradually with an increase in SiC content.When the mass ratio was 1.3:1(S4),the further increase of SiC had no significant effect on the shrinkage of the support.This phenomenon indicates that the addition of SiC can help to prop up the supports,which reduces the shrinkage of the support effectively and ensures that the support has a large number of pores.It can be explained that SiC is not affected by temperature at 700°C[22,29],the structure of the support is basically unchanged,and so the support has a certain mechanical strength and porosity.

Fig.3.The SEM of supports with SiC(A)and without SiC(B)(A1 B1 top surfaces,A2 B2 cross sections).

The porosity and mechanical strength of the support that was prepared with different LPGS/SiC mass ratios are shown in Fig.4B.Fig.4B(b)shows that when the mass ratio is 2:1,the open porosity of the support reached 40.05%±0.5%.With the further increase in SiC,the open porosity of the support fluctuated slightly,but overall,the open porosity remained above 38%.

Fig.4B(a)shows that the mechanical strength of the support increases first and then decreases slightly with the increase in SiC.For a mass ratio of 2:1,the mechanical strength was 15.57 MPa.It can be explained that when the SiC content was low,the support contained large amounts of LPGS,and when the support was sintered at 700 °C,the LPGS underwent dehydration shrinkage.A small amount of SiC cannot prevent the support from shrinking,which results in a lower mechanical strength.When the mass ratio of the support was between 1.7:1 and 1.2:1(S2–S5),the proportion of SiC increased,in the roasting process,a neck connection could form between the LPGS and SiC particles,which improved the strength of the support and shrinkage could be prevented because of the presence of SiC particles.When the mass ratio was 1.1:1(S6),the mechanical strength decreased significantly because the content of LPGS in the support was relatively low,and SiC played a major role.There was no particle interaction for SiC at a sintering temperature of 700°C[22,29],so the mechanical strength of the support was reduced,and the porosity increased.

3.4.Effects of pore-forming agent content

To increase the porosity of the support and improve its permeability,carbon powder was added as a pore-forming agent.According to the experimental results in Section 3.3,the appropriate mass ratio must be selected.Here,we selected a LPGS/SiC mass ratio of 1.7:1.Our group investigated the influence of carbon powder content of 5%,6%,7%and 8%on the performance of the supports at the same sintering temperature.The experimental results are shown in Fig.5.Fig.5 shows that with an increased in carbon powder content,the open porosity showed an upward trend,whereas the mechanical strength showed a downward trend because of the competitive relationship between the open porosity and mechanical strength[33,34].In other words,there is a similar“trade-off”effect between the mechanical strength and porosity of the support[22].When the carbon powder content increased from 5%to 8%,the porosity increased from 38.23%±0.19%to 43.77%±0.21%(Fig.5(B)).Which can be explained that the increase in carbon powder lead to an increase in the ignition loss,and the pores between the particles increased,which resulted in an increase in the open porosity of the support.

When the carbon powder content increased from 5%to 6%,the mechanical strength decreased slowly,but remained above 17.0 MPa.When the carbon powder content increased to 8%,the mechanical strength decreased sharply.The mechanical strength was only(11.9±0.51)MPa(Fig.5(A))because the addition of carbon powder decreased the contact area between the SiC and LPGS grains and weakened the binding.

3.5.Effects of sintering additives

To counteract this competitive relationship(“trade-off”effect),the addition of reinforcement materials is required.Many metal oxides can increase the ceramic strength by in situ reaction bonding.However,the cost of many materials is high and accumulates easily in holes,which results in a decreased of pore size and open porosity.V2O5can bind particles to increase the mechanical strength via bridging without adversely affecting the open porosity.Because of its low melting point,liquid phase sintering can occur during the sintering.Fig.6 shows a schematic diagram of the evolution of V2O5particle shape,the LPGS can form three-dimensional(3D)network structures and enlarge the spatial structure with V2O5addition.It can also be seen from Fig.7 that the PGS rod crystal structure is complete,V2O5exists on the surface of the support,and stable 3D network structure has been formed,which also confirms the previous hypothesis.

Fig.4.Effect of LPGS/SiC ratio on shrinkage of the support(A)and the mechanical strength and porosity(B).

Fig.5.Effect of content of pore-forming agent on mechanical strength(A)and porosity(B)of the support.

Fig.6.Schematic diagram of V2 O5 particle shape evolution.

For a mass ratio of LPGS/SiC of 1.7:1(S2),the content of carbon powder was 6%,the content of V2O5was 0%,1%,2%,3%,4%,5%and 6%,respectively,and the supports was sintered for 3 h at 700°C in air.The mechanical strength and open porosity were investigated,the results are shown in Fig.8.As can be seen from Fig.8,the porosity and mechanical strength increased first and then decreased with an increased in V2O5content.The open porosity increased to 42% ± 0.48% (Fig.8B)after incorporating 5%V2O5,and the mechanical strength reached 23 MPa(Fig.8A).The most reasonable explanation for this effect is that LPGS can form three-dimensional(3D)network structures and enlarge the spatial structure with V2O5addition(Fig.6)[35].After melting and cooling,V2O5became the anchor points of the 3D network structure and formed the neck connection,which can increase the mechanical strength(Fig.6).When more than 5%V2O5was added,the mechanical strength and porosity decreased gradually.The loss of porosity can be explained from the nonuniform dispersion of V2O5and the liquid phase of V2O5entered the channel.Alternatively,the anchor points of the 3D structure increase,which can lead to a reduction in porosity.Because of the increase in V2O5,the V2O5liquid phase increases,which can result in a decrease in the contact area between particles.Therefore,a stable neck connection cannot be formed between particles,and the mechanical strength is reduced obviously.However,a large number of LPGS fibers and the anchor points of the 3D structure make up the primitive microcracks of the support,so the microcracks will stop growing and prevent the material from fracturing.In this way,V2O5doping could offset the trade-off effect of porosity and strength.

3.6.Effects of forming pressure

The porosity and mechanical strength of the support along with the change of the forming pressure are shown in Fig.9.

It can be seen that the mechanical strength increases and the porosity decreases with an increase of forming pressure.When the forming pressure increased from 8 MPa to 16 MPa,the mechanical strength increased from 15 MPa to 30 MPa,and the porosity decreased from 48%to 35%.This phenomenon can be summarized as follows:with the increase of forming pressure,the gap between the particles reduced,and the gap of burning loss reduced,so the porosity decreased(Fig.9(B)).At the same time,due to the gap reduction,the interaction between particles during sintering was enhanced,so it was easier to form stable neck connections between particles (Fig.9(A)).When the forming pressure was 10 MPa,the mechanical strength of the support was (23.34 ± 0.53) MPa and the porosity was 41.02%±0.47%.

Fig.7.The SEM of the supports with V2 O5 sintering additives.

Fig.8.Effect of content of V2 O5 on mechanical strength(A)and porosity(B)of the support.

3.7.Effects of sintering temperature

Fig.9.Effect of forming pressure on the mechanical strength(A)and porosity(B)of the support.

The porous ceramic support requires a high porosity and high strength to meet the function and engineering requirements.These two contradictory performance requirements need to be achieved by adjusting the sintering temperature and holding time [36].When sintering at a lower temperature,there is no interaction between the particles,which can decrease the properties of the support.When sintering at a higher temperature,the particles grow quickly,which can result in sintering densification and a decrease in the properties of the support (Fig.10B).So an appropriate sintering system can not only yield a good mechanical strength,but also increase the connectivity of pores in the support,increase the gas flux of the support,and improve the porosity without a loss of mechanical strength(Fig.10A).

Our group has found that when the sintering temperature exceeds 750°C,obvious cracks and defects exist on the surface of the support(Fig.10B).Therefore,we only investigated the properties of the supports when the sintering temperature was below 700 °C.Fig.11 shows the mechanical strength and porosity at different sintering temperatures for 3 h in air.When the sintering temperature was 650°C,the mechanical strength and porosity were(11±0.55)MPa and 42.35%±0.32%,respectively.With an increase in sintering temperature,the values of the support increase,and the mechanical strength and porosity were(17.76±0.6)MPa and 44%±0.3%when sintered at 700°C.Which can be explained that the higher the sintering temperature,the stronger interaction between particles [29].Therefore,when the sintering temperature is 650°C,the interaction between particles is small,stable neck connections cannot be formed and small particles exist in the support.When the sintering temperature is 700°C,the particles interact strongly to form stable neck connections(Fig.10A).As the temperatures increases,small particles inside the support melt into larger particles or form neck connected phases,so when the sintering temperature is 700°C,the performance of the support increases.

Fig.12 shows the gas flow of the support with pressure.The gas flow rate demonstrated a linear relationship with pressure.The gas flow was higher for samples sintered at 700°C because of the higher open porosity and larger number of interconnected pores,with a maximum gas permeability of 6.69×105m·h?1·MPa?1.The gas permeability of the support that sintered at 650°C was 4.15×105m·h?1·MPa?1.

3.8.Evaluation of acid–base resistance of supports

Acid–base corrosion resistance of porous ceramic supports is an important factor to evaluate the quality of supports.As a porous support that provides the strength of ceramic membrane,the acid–base corrosion resistance directly affects the stability and separation effect of ceramic membrane.The mass loss percentage and mechanical strength loss percentage were used to evaluate the samples before and after corrosion.Acidic conditions:concentrated sulfuric acid with a volume fraction of 20%,alkaline conditions:NaOH solution with a mass fraction of 1%,held for 12 h at 80°C.

Table 2,Fig.13 shows the mass comparison and the mechanical strength comparison of the support before and after the acid and alkali corrosion,respectively.

Fig.10.SEM of the supports at different sintering temperatures(A 700°C;B 800°C).

As shown in Table 2 and Fig.13,the average percentage of mass loss in acid is 1.05% ± 0.07%,and the mechanical strength is reduced by 19.48%,while the average percentage of mass loss in alkali is 0.56% ± 0.03%,and the mechanical strength is reduced by 11.36%.

This is because the SiC and silica (in LPGS) are acid resistant and less corrosive to acids.Simultaneously,LPGS is alkali resistant(pH=8) and the LPGS structure is not completely decomposed,resulting in low corrosion in alkaline environment [19].It is found that the corrosion of the support in acid is greater than that in alkali,because LPGS contains impurities that are soluble in acid,and corrosion is greater under acidic conditions.In general,this support can meet the production requirements in acidic and alkaline environments.

Fig.11.Effect of sintering temperature on mechanical strength(A)and porosity(B)of the support.

3.9.Comparison of performance of the supports

Fig.12.Gas flow versus pressure with different sintering temperatures.

Table 2 Acid and alkali corrosion test

Fig.13.The influence of acid and alkali corrosion of mechanical strength.

Many researchers have developed porous ceramic supports with different materials and methods due to the excellent performance of the supports.Table 3 shows the open porosity,mechanical strength,mean pore size and sintering temperature of different porous materials.As can be seen from Table 3,the sintering temperature of the support prepared here was lower than that reported previously for other materials and the mechanical strength was higher.The pore size of the support that was prepared here was smaller,but the porosity was higher,which can explain the formation of many interconnected pores in the support[29,38–41].Because of the rich raw materials,many sources of LPGS and low sintering temperature,the preparation cost of the support is relatively low.

4.Conclusions

A high-performance,low-cost palygorskite clay ceramic support was successfully prepared by dry-press forming and in situ sintering.An appropriate amount of SiC addition as aggregate to low-grade palygorskite clay ceramic support can prevent excessive shrinkage of the support effectively during sintering,reduce its shrinkage rate from 30%±0.12%to 2.25% ± 0.05%,and increase the mechanical strength and porosity of the support greatly.Because of its low melting point,V2O5can be melted into liquid during sintering,which increases the mechanical strength and the porosity remains unchanged.When the mass ratio of LPGS/SiC was 1.7:1,with a 6%carbon powder pore-forming agent,5%V2O5sintering additive,10 MPa forming pressure and 700°C sintering temperature,the average mechanical strength was(17.76±2.03)MPa,and the porosity was 44%±0.3%.The porous ceramic support from low-grade palygorskite clay can improve the utilization value of palygorskite and yield a lowcost porous ceramic support.

Acknowledgements

The authors are grateful for the financial support of the National Natural Science Foundation of China(No.21978109,21878118),Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJA430011),Natural Science Foundation of Jiangsu Province(BK20171268),Jiangsu Province industry-university-research cooperation project(BY2019179),Jiangsu Qing Lan Project.

Table 3 Performances of the support and prices of different porous materials

Supplementary Material

Supplementary data to this article can be found online at https://doi.org/10.1016/j.cjche.2020.08.018.