Fraction Of Micropores Research Articles

The effect of KOH concentration on chemical activation of porous carbon sorbents for carbon dioxide uptake and carbon dioxide–methane selectivity: the relative formation of micro- (<2 nm) versus meso- (>2 nm) porosity

Porous carbon (PC) sorbents are synthesized from polymer precursors mixed with a chemical activation reagent and pyrolised (>500 °C). KOH is known to be the best activator for a wide range of precursors, as it creates PCs with a large surface area (1200–4000 m2 g−1). In order to determine the optimum KOH : polymer ratio for both CO2 adsorption and CO2/CH4 selectivity, we prepared a set of five S-containing porous carbon (SPC) samples from polythiophene (PTh) with increasing KOH : PTh ratio (1 to 5), and investigated CO2 and CH4 uptake measurements on carbonaceous SPC samples up to a pressure limit of 30 bar. The SPCs have been characterised by XPS, SEM, TEM and BET surface area analysis. Although the apparent surface area and total pore volume increased with increasing KOH concentration, the maximum CO2 uptake (5–30 bar) was demonstrated for samples with KOH : PTh = 3. This equates to SPC samples with a surface area and total pore volume of ∼2700 m2 g−1 and 1.5 cm3 g−1, respectively. Greater values for either parameter do not enhance the CO2 uptake, showing that it is not total porosity that is important. SPC samples formed with KOH : PTh = 3 show both a maximum C composition (85%), and a maximum fraction of micro-pores ( 2 nm). KOH : PTh = 3 is also the synthetic condition to maximise CH4 uptake (5–30 bar); however, the optimum CO2/CH4 selectivity occurred with KOH : PTh = 2. This correlates with a different surface area (2200 m2 g−1) and total pore volume (1.2 cm3 g−1) that are required for optimum CO2 uptake. These results suggest that process conditions that lead to high relative microporosity need to be considered rather than the total surface area or pore volume.

Dual incorporation of SiO 2 and ZrO 2 nanoparticles into the oxide layer on 6061 Al alloy via plasma electrolytic oxidation: Coating structure and corrosion properties

Abstract The present work investigated the influence of SiO 2 and ZrO 2 incorporated nanoparticles on the coating structure and the corrosion behavior of 6061 Al alloy coated by plasma electrolytic oxidation (PEO). To achieve this purpose, a set of PEO treatments were conducted in alternating current condition at a constant current density of 130 mAcm −2 in phosphate electrolytes containing each and both nanoparticles, respectively. Microstructure observations revealed that when SiO 2 or/and ZrO 2 nanoparticles were added to the electrolyte, both size and fraction of micropores tended to be decreased, which would be attributed to the incorporation of nanoparticles. SiO 2 nanoparticles were preferentially embedded in the vicinity of micropores, meanwhile ZrO 2 nanoparticles preferentially filled the cracks. m -ZrO 2 was mostly converted to o -ZrO 2 while SiO 2 were partly converted to o -SiO 2 and another part to mullite. Based on potentiodynamic polarization tests in 3.5 wt% NaCl solution, the coatings containing both SiO 2 and ZrO 2 nanoparticles exhibited excellent corrosion protection properties due to the combination of their roles as the micropores blocker and cracks filler so that the microstructural defects were minimized.

Kinetics of adsorption of pharmaceutical substances from aqueous solutions on activated carbons

The article has investigated regularities of adsorption of sulfanilamide, sulfathiazole, procaine, levamisole and caffeine on activated carbons of various porous structure. The adsorption rate of substances diminishes in the series sulfanilamide > caffeine > procaine > sulfathiazole > levamisole and decreases with an increase of the fraction of micropores in the structure of sorbents. It was found that at the degree of using the adsorption capacity of the sorbent of up to γ = 0.5–0.6 the kinetics of adsorption satisfactorily is described by means of an external diffusion model. The use of 50% of sorption capacity of activated carbon is achieved over ~ 10% time necessary for establishing adsorption equilibrium.

Hemp-derived activated carbons for supercapacitors

Activated carbons are prepared from raw hemp stem (hurd and bast) via hydrothermal processing and chemical activation. Both hemp bast and hemp hurd are converted into activated carbons of low-dimensional structures under certain experimental conditions. The experimental results show that hemp hurd is a better precursor than hemp bast for the preparation of activated carbons. The activated carbons are used to construct the electrodes of supercapacitor cells. The electrochemical performance of the activated carbons used in the supercapacitor cells is dependent on hydrothermal processing conditions and the mass ratio of KOH/biochar in the chemical activation. Excellent electrochemical performance metrics are achieved, including a specific capacitance of 160 F/g, and a high energy density of 19.8 Wh/kg at a power density of 21 kW/kg. Both the specific capacitance and capacitance retention increase with the increase of surface area and mesopore fraction. A simple relationship between the specific area capacitance and the fraction of micropores is proposed, via the rule of mixtures, and is supported by the experimental results. This relationship reveals the effect of the distribution of pore sizes on the specific area capacitance of electrochemical double layer capacitors.

Chemical and physical characteristics of optimal synthesised activated carbons from grass-derived sulfonated lignin versus commercial activated carbons

This study aims to evaluate the surface characteristics and chemistry of optimal activated carbons (ACs) synthesised from water-soluble grass-derived sulfonated lignin (SL) using three dehydrating salts (ZnCl2, KCl and Fe2(SO4)3·xH2O). The optimal AC synthesised by each dehydrating salt was chosen as the carbon that achieved the highest removal efficiency of Cd2+, Cu2+ and Zn2+ ions from aqueous solutions. These optimal sulfonated lignin-based activated carbons (SLACs) showed the highest surface areas, total pore and micropore volumes among all the synthesised ACs. These SLACs were named SLAC-ZC (optimal grass-derived SLAC activated by zinc chloride); SLAC-PC (optimal grass-derived SLAC activated by potassium chloride) and SLAC-FS (optimal grass-derived SLAC activated by ferric sulphate). The surface characteristics of two commercial activated carbons (CAC1 and CAC2) were also appraised for comparison purposes. The optimal SLACs showed similar, or even better, properties to the two CACs. The N2 adsorption/desorption isotherms showed that the micropore fraction of SLAC-ZC was greater and its mesopores were narrower than SLAC-PC. For SLAC-FS, the amount of adsorbed N2 was markedly lower than all other ACs and hence its values of BET surface area (ABET) and total pore volume (Vtotal) were the lowest. The iodine volume capacities of SLAC-ZC and SLAC-PC were higher than CAC1, suggesting that they could operate better in continuous adsorption processes. FTIR and SEM analysis illustrated that chemical activation had changed the surface chemistry of SL. Overall; synthesis of ACs from this novel precursor will add value to sulfonated lignin, which is considered as an industrial waste.

The impact of organic amendments on soil hydrology, structure and microbial respiration in semiarid lands

Few studies have considered the effect of organic amendments on soil microbial activity and its contributions to hydraulic conductivity under field conditions in semiarid region soils with different textures and degrees of aggregate stability. This study was performed to investigate the relationship between selected soil properties and hydraulic conductivity in response to different types and application rates of organic amendments. For this purpose, urban municipal solid waste (MSW) compost and alfalfa residue (AR) were applied at different rates of 0 (control), 10Mgha−1 and 30Mgha−1 to clay loam and loamy sand soils under field conditions. Results show that after two years, MSW-treated soils had lower soil organic carbon (SOC) compared to those treated with AR due to higher CO2 emissions from the soils treated with MSW. Higher microbial respiration and mineralization quotient (qmC) in the MSW-treated soils resulted in higher levels of water stable aggregates (WSA>0.25mm) and more macro-pore fraction, leading to greater hydraulic conductivity, with larger increases at the higher rate of application (i.e. 30Mgha−1). Relative to the control treatment, the application of MSW caused greater increases in microbial respiration in the clay loam soil than in the loamy sand soil, whereas the reverse was found for AR. Apart from soil texture, aggregate size was found to play an important role in controlling the carbon stock and microbial respiration of soils and consequently hydraulic conductivity. The macro-pore fraction was more sensitive than the micro-pore fraction to the application of organic amendments. Correlation analysis indicated that during the reclamation process higher levels of microbial respiration, SOC, water stable aggregates and macro-pore fraction were associated with greater soil hydraulic conductivity.

Mesoporous silica materials with different structures as the carriers for antimicrobial agent. Modeling of chlorhexidine adsorption and release

The present study was aimed to evaluate the potential of five different mesoporous materials (SBA-15, compressed SBA-15, PHTS, SBA-16, MCF) as the carrier for chlorhexidine adsorption and release. All the materials were characterized by large specific surface area ∼700m2, however their pore volume and pore geometry were substantially different. Langmuir, Freundlich and Dubinin–Radushkevich isotherm models were applied to experimental equilibrium data of chlorhexidine adsorption onto examined mesoporous materials. In all experiments, the commercial silica was used as a reference material. The highest maximum adsorption capacity calculated from the Langmuir model of 416.7 and 357.1mg/g was observed for SBA-15 and MCF silicas, respectively. Meanwhile, SBA-16 material was characterized by the lowest maximum adsorption capacity of 85.5mg/g. To compare the chlorhexidine dissolution profiles, four release models were tested such as Higuchi, Korsmeyer–Peppas, Baker–Lonsdale and Weibull. Mesoporous matrices with increased micropore fraction (PHTS, SBA-16) exhibited markedly prolonged release of chlorhexidine as compared to other silicas. The time interval necessary to dissolve 63.2% of chlorhexidine present in the formulation calculated from the Weibull model (t63.2%) reached the highest values of 203.5 and 308.5h for PHTS and SBA-16 silicas, respectively.

Adsorption characteristics of propan-2-ol vapours on activated carbon Sorbonorit 4 in electrothermal temperature swing adsorption process

Adsorption characteristics of propan-2-ol on Sorbonorit 4 activated carbon were determined using the breakthrough curve tests in a cyclic electrothermal temperature swing adsorption process. Maximum adsorption capacity, breakthrough time, throughput ratio and length of unused bed were also evaluated. As a result of multiple regeneration, the adsorption capacity of Sorbonorit 4 increased. Electrothermally-induced changes in the internal structure of Sorbonorit 4 and in the chemical composition of its surface were assessed based on adsorption equilibrium measurements by the gravimetric method and X-ray photoelectron spectroscopy (XPS). Three samples of virgin, direct resistively heated and electrothermally regenerated Sorbonorit 4 were used. The structural characteristics of activated carbon show that that fresh and direct resistive heated Sorbonorit 4 has a bimodal structure. Regenerated activated carbon contains one fraction of micropores. XPS analysis revealed that the same hydroxyl, carbonyl and carboxyl groups were found on the surface of all Sorbonorit 4 samples, albeit in different volume ratios. Regenerated Sorbonorit 4 has higher adsorption capacity than pure adsorbent while resistively heated Sorbonorit 4 displays lower adsorption efficiency.

Capillary Forces and Sorption Hysteresis of Cement Pastes with Small Slit Pores

Cement-based materials often display an extraordinarily pronounced hysteresis of water sorption isotherms, even at low vapor pressures. This hysteresis is reflected in the volume change of the solid skeleton. To explain these observations, we propose a simple mechanism based on strong capillary forces in slit pores. Condensed water can exert capillary forces that change the volume of pores which are embedded in elastic solids. A macroscopic model predicts a pronounced sorption hysteresis for soft materials with narrow slit-shaped pores. The proposed mechanism can also be the origin of hysteresis in more rigid materials such as hardened cement pastes, which have a large fraction of micropores.

Carbon materials from the Sibunit family and methods for controlling their properties

The methods of regulating the porous structure and properties of carbon materials of the Sibunit type are considered. The deposition to 10–15 wt % pyrolytic carbon in the pore space of Sibunit makes it possible to regulate pore volume and pore-size distributions by decreasing the fraction of micropores and small mesopores and to enhance the strength characteristics of the support. Heat treatment in an inert atmosphere in a temperature range of 2200–2600°C imparts a number of unique specific properties to the Sibunit supports, in particular, high resistance to oxidative and electrochemical corrosion, which is comparable with the resistance of graphite. At the same time, it retains sufficiently high pore structure characteristics and adsorption properties typical of porous carbon materials. The introduction of water-soluble organic compounds capable of producing microporous carbon upon carbonization at the stage of granulation or the supporting of organic compounds on Sibunit with the subsequent polymerization and carbonization in the support pores makes it possible to form micropores with a volume to 0.20–0.25 cm3/g in Sibunit.

A study on elemental mercury adsorption behaviors of nanoporous carbons with carbon dioxide activation

In this work, nanoporous carbons (NPCs) were prepared by the self-assembly of polymeric carbon precursors and block copolymer template in the presence of tetraethyl orthosilicate and colloidal silica. The NPCs' pore structures and total pore volumes were analyzed by reference to /77 K adsorption isotherms. The porosity and elemental mercury adsorption of NPCs were increased by activation with carbon dioxide. It could be resulted that elemental mercury adsorption ability of NPCs depended on their specific surface area and micropore fraction.

Modifying Effect of Betulinol on Carbon Sorbents Produced from Betula birch Wood

A lack of high-quality carbon adsorbents (CA) with a uniform microporous structure is the main impediment to the development of new and the improvement of existing adsorption methods for purifying and separating gases. The sorbent structure, i.e., the size, volume, and ratio of principal pore types, is determined by the nature of the precursor and its processing into activated carbon. As a rule, the porosity of carbonized carbons from wood and plant material is known to be disorganized. Structure formation in a particular direction is difficult to regulate accurately. The sizes and distribution of pores in CA could possibly be controlled by modifying the porosity of finished activated carbon with an organic binder and/or a pore-former or by applying a layer of organic polymer or hydrocarbon thermal decomposition products to the carbon substrate [1]. The goal of the present work was to study the effect of modifying the porous structure of previously carbonized Betula birch wood with betulinol and subsequent activation with KOH on the properties of the produced CA. It was found that thermochemical activation (800°C, 1 h) of previously carbonized (300–800°C) B. birch wood in the presence of KOH promoted the formation and development of micropores. The resulting carbon materials were distinctly porous and absorbed a broad spectrum of chemicals (benzene, hexane, CCl4, H2O, etc.). The carbonized (400°C) B. birch wood sample that was activated by KOH (3:1) (CBW-400/KOH) had the highest specific surface area (SBET 1980 m 2/g) and total pore volume (0.83 cm3/g) [2]. As the carbonization temperature was raised from 600 to 800°C, the KOH-activated CA were highly selective for the separation of a model mixture of H2(He) and CH4. Their separation coefficients (Ks) were 3.0–3.8, were used as criteria of the separating capability, and were estimated by chromatography. This represented a high degree of separation for He–CH4 [3]. The possibility of improving the Ks values by regulating the reactivity of the B. birch precursors that were carbonized at 500–800°C was studied. Existing pores were modified by the natural product betulinol (25 mass%) and then activated by KOH. Betulinol (betulin) is the pentacyclic lupane triterpene alcohol C30H50O2 with MW 442.7. It was isolated by extraction from B. birch bark. A coating of pyrolyzed carbon will form on the external surface of the carbon if the organic modifier is used under conditions where it is selectively decomposed (450°C). The carbon composite formed at this point is activated by KOH, which is effective on both components. As a result, modified CA with a controlled capability for selective adsorption and separation of H2(He)–CH4 mixtures were produced at 800°C. The effect of the organic modifier on the CA porous structure was studied using CBW (700°C) activated by KOH (CBW-700/KOH) as an example. Figure 1 shows the N2 adsorption isotherms at 77 K under standardized conditions (Fig. 1). The N2 adsorption isotherms for unmodified CBW-700/KOH (Fig. 1, 3) and for CA from pure betulinol (Fig. 1, 2), which was prepared for comparison under analogous KOH activation conditions, were characteristic of microporous materials. The shape of isotherm 1 was indicative of further pore development throughout the whole volume of CBW-700 because of modification with betulinol and subsequent activation by KOH. The fraction of micropores increased because pieces of pyrolyzed material were located near the entrances to larger pores. This shifted the pore-size distribution to a predominant size up to 1.8 nm (~90%) and gave a more uniform microtexture that was more favorable for He-CH4 separation. The Ks values of the modified CA from B. birch wood (Ks = 3.87–4.11) exceeded those of CA that were prepared analogously but were unmodified (Ks = 3.0–3.8) [3]. Table 1 shows that the modifying action of betulinol and subsequent activation by KOH were manifested best at carbonization temperatures of 600–800°C. Modified sample CBW-700 had the highest Ks value (4.11) for H2(He)–CH4 under controlled KOH activation conditions.

Preparation and characterization of chemically activated carbons derived from Mediterranean Posidonia oceanica (L.) fibres

In the present work, the preparation of several chemically activated carbons (CACs) from marine Posidonia oceanica fibrous biomass was performed using various activating agents. The chemical activation was carried out using phosphoric acid (H3PO4), potassium hydroxide (KOH), zinc chloride (ZnCl2) and hydrogen peroxide (H2O2). The effects of those impregnating agents were investigated for all produced CACs via several chemical and structural analyses.The results showed that H3PO4 seems to induce the deepest impact on the P. oceanica fibres by providing the lowest conversion yield (16.9%). Besides, the pore analysis showed that two types of porosity were developed: (i) CACs characterized by an inner structure combining significant fraction of both mesopores and micropores (i.e. CAC-H3PO4, CAC-KOH and CAC-ZnCl2) and (ii) CAC-H2O2 with a large mesoporous structure and a small fraction of microporosity. Dealing with the RAMAN and XPS analysis, it was showed that the main carbon fraction is structurally organized (i.e. graphite), especially for the CAC-ZnCl2 sample. As for the isotherm and kinetic investigation, the experimental and modelling results revealed that CAC-H3PO4 was the best performing activated carbon by removing the highest methylene blue dye amount (137mg/g) in the shortest time (1.3h to reach the half reaction point).

Formation of micro- and mesoporous substructures in the course of the leaching process of two-phase alkali borosilicate glass

The influence of the acid leaching conditions (duration, HCl concentration) of phase-separated alkali borosilicate glass with composition 7.6Na2O · 20.4B2O3 · 71.9SiO2 · 0.1Al2O3 on the porous glass (PG) structure formation has been studied with diagnostics of meso- and micropores. The morphology of the PG pores has been investigated with the use of the equilibrium and kinetic adsorption-desorption methods at low, medium, and high relative pressures. It has been established that all PG samples under study were characterized by a polymodal pore size distribution with micropore sizes ranging from 0.45 to 0.70 nm (up to 3 modes) and mesopores (from 2 to 4 modes, with a dominant bimodal distribution). At the end of the acid leaching process and with an increasing duration of treatment and acid concentration, the secondary silica structuring in the liquation channels takes place. In addition, the fraction of liquation channels free of secondary silica particles decreased, the width of the second peak attributed to mesopores increased, with a modification of their shape and packing. The fraction of micropores in the total volume of accessible pores decreased from 7.5 by up to 5.5%.

Effects of Pore Structure on the High-Performance Capacitive Deionization Using Chemically Activated Carbon Nanofibers

Capacitive deionization (CDI) electrodes were constructed from activated carbon fibers prepared using electrospinning and chemical activation. The CDI efficiencies of these electrodes were studied as a function of their specific surface areas, pore volumes and pore sizes via salt ion adsorption. The specific surface areas increased approximately 90 fold and the pore volume also increased approximately 26 fold with the use of greater amounts of the chemical activation agent. There was a relative increase in the mesopore fraction with higher porosity. A NaCI solution was passed through a prepared CDI system, and the salt removal efficiency of the CDI system was determined by the separation of the Na+ and Cl- ions toward the anode and cathode. The CDI efficiency increased with greater specific surface areas and pore volumes. In addition, the efficiency per unit pore volume increased with a reduction in the micropore fraction, resulting in the suppressed overlapping effect. In conclusion, the obtained improvements in CDI efficiency were mainly attributed to mesopores, but the micropores also played an important role in the high-performance CDI under conditions of high applied potential and high ion concentrations.

Poly(ethylene glycol) as structure directing agent in sol–gel synthesis of amorphous silica

Porous amorphous silica obtained by the sol–gel method with poly(ethylene glycol) (PEG) as structure directing agent is investigated. In this paper, we use the PEG with molecular weight 400, 1300, 3000, 6000, 20,000, 100,000, 200,000 and vary the concentration of the polymer solution in a wide range. The analysis of nitrogen adsorption–desorption data and transmission electron microscopy shows that depending on the combination of molecular weight and concentration of the PEG solution the microporous and mesoporous silica materials can be obtained. It was determined that using the solution of PEG-400, 1300 independently of the concentration the mesoporous silica is formed. When the diluted and concentrated solutions of PEG-3000, 6000, 20,000, 100,000, 200,000 are used it produces also the mesoporous materials. In the field of transitional concentrations of PEG the microporous silica with fraction of micropores equals 95% is generated. Revealed regularities are generalized and shown on the texture diagram.

A fluorene based covalent triazine framework with high CO2and H2capture and storage capacities

Porous organic polymers have come into focus recently for the capture and storage of postcombusted CO2. Covalent triazine frameworks (CTFs) constitute a nitrogen-rich subclass of porous polymers, which offers enhanced tunability and functionality combined with high chemical and thermal stability. In this work a new covalent triazine framework based on fluorene building blocks is presented, along with a comprehensive elucidation of its local structure, porosity, and capacity for CO2 capture and H2 storage. The framework is synthesized under ionothermal conditions at 300–600 °C using ZnCl2 as a Lewis acidic trimerization catalyst and reaction medium. Whereas the materials synthesized at lower temperatures mostly feature ultramicropores and moderate surface areas as probed by CO2 sorption (297 m2 g−1 at 300 °C), the porosity is significantly increased at higher synthesis temperatures, giving rise to surface areas in excess of 2800 m2 g−1. With a high fraction of micropores and a surface area of 1235 m2 g−1, the CTF obtained at 350 °C shows an excellent CO2 sorption capacity at 273 K (4.28 mmol g−1), which is one of the highest observed among all porous organic polymers. Additionally, the materials have CO2/N2 selectivities of up to 37. The hydrogen adsorption capacity of 4.36 wt% at 77 K and 20 bar is comparable to that of other POPs, yet the highest among all CTFs studied to date.

Production and Characterization of Activated Carbon from Çanakkale-Çan Lignite by KOH and ZnCl2 Activation

Activated carbon was produced from Canakkale-Can lignite using potassium hydroxide (KOH) and zinc chloride (ZnCl2) as activating agent. The influence of carbonization temperatures (500-900 0C) and different chemical reagents (KOH and ZnCl2) on the pore development and the yield of the prepared activated carbon were investigated. The resultant activated carbons were characterized in terms of the yield, BET surface area, pore volumes, micropore and mesopore fraction. Results showed that increasing the carbonization temperature, the yield decreased, while surface area and micro-porosity increased. Maximum surface area was about 1092 m2/g at 900 0C with KOH activation and carbonization duration of 1 h. The surface area of char obtained from carbonization of lignite sample without impregnation by chemical reagent was 157 m2/g at 900 0C. From these data, it has been showed that in order to produce activated carbons with high surface area and porosity, thermal activation (without impregnation) itself is not sufficient. The prepared activated carbon was compared with commercial activated carbon. Surface area and micropore fraction of activated carbons obtained from both KOH and ZnCl2 activation much larger than those of the commercial activated carbon.

Poly(ionic liquid) nanoparticles as novel colloidal template for silica nanocasting

Spherical poly(ionic liquid) (PIL) nanoparticles of different size (25–70 nm) were synthesized and applied as a novel colloidal soft template for the preparation of meso- and macroporous inorganics, here exemplified with silica and its metal nanoparticle doping via nanocasting. Pore size and pore architecture can be adjusted by appropriate choice of the template and the reaction conditions. Unexpectedly, it was found that the in situ generated methanol plays a very important role during the casting process. It enlarged the overall surface area by introducing a significant fraction of micropores and small mesopores. The largest specific surface area was obtained at an optimized ratio of tetramethyl orthosilicate (TMOS) to PIL nanoparticle. In addition, PIL nanoparticles pre-functionalized with Pt metal nanoparticles were used in the same manner as hybrid templates for nanocasting. The pyrolysis conditions were optimized to synthesize mesoporous silica functionalized with uniformly distributed metal nanoparticles of very small size in a one-pot process.

In-situ generation of large microporous skeleton in mesoporous silica framework using different dicarboxylic acids

Mesoporous Santa Barbara Amorphous-15 is known to possess a small fraction of micropores, in the walls of mesopores. The ratio of micropore to mesopore area can have a profound influence on the application of this highly ordered material in various fields. The present work aims to investigate the influence of dicarboxylic acids as organic structure interrupting agents on the micropore to mesopore ratio. The physiochemical characterization of the synthesized samples including electron microscopy, nitrogen adsorption–desorption isotherms, MAS 29Si-NMR, FT-IR demonstrate a distinct change in the morphology and micropore area due to the different dicarboxylic acids used during synthesis. Our results show that the decrease in chain length of the dicarboxylic acid has a direct relation to the increase in micropore area which has a significant role in the adsorption properties of mesoporous silica. Thus the dicarboxylic acid mediated tuning of the micropores area of mesoporous silica can be used for various applications.