Adsorption Of P-nitrophenol Research Articles

DFT study on the adsorption of p-nitrophenol over vacancy and Pt-doped graphene sheets

The frequent and widespread use of p-nitrophenol at commercial scale is giving rise to several health hazards among living beings and damage to the ecosystem. In this work, the adsorption of para-nitrophenol (p-NP) on pristine/vacancy-graphene and Pt4-cluster doped graphene systems are investigated using density functional theory (DFT). Two modes of adsorption have been considered: perpendicular and parallel. While adsorption of p-NP on the pristine graphene substrate is unfavorable, it is found that the adsorption capacity of graphene can be significantly increased by creating defects and by doping with Pt-clusters. Different electronic properties, like partial density of states (PDOS), reveal that on doping with a Pt-cluster, the band gap of the surface decreases and the substrates start showing magnetic character. Electron density difference plots give insights into the adsorption behavior of p-NP.

Organo-vermiculites modified by low-dosage Gemini surfactants with different spacers for adsorption toward p-nitrophenol

Butyl group and unsaturated groups (2-butenyl, 2-butynyl and dimethylphenyl) have been introduced as spacers of Gemini surfactants for modifying vermiculite (VT) to exploit easily industrialized adsorbents and to explore systematically the effects of spacers on the adsorption of p-nitrophenol (PNP). Four organo-vermiculites (OVTs including 12-A-12-VT (alkyl), 12-P-12-VT (dimethylphenyl), 12-E-12-VT (2-butenyl), 12-Y-12-VT (2-butynyl)) have been prepared successfully and characterized by FT-IR, XRD, TG, SEM, BET, elemental analysis and Zeta potential. The results show that the four have low saturated adding amount of surfactant (0.4 CEC), and 12-A-12 with flexible alkyl group shows markedly higher loading amount (18.8 wt%) on VT than the three surfactants with rigid unsaturated spacer (16.7 wt%, 15.7 wt% and 15.4 wt%). The batch experiment results of OVTs to PNP demonstrate that the four are ranked by adsorption capacity as follow: 12-A-12-VT > 12-P-12-VT > 12-E-12-VT ≈ 12-Y-12-VT, their maximum adsorption all occur at pH = 6 within 20 min and 12-A-12-VT possess stronger removal capacity (qmax = 106.5 mg/g) than other clay-based adsorbents. Furthermore, Kinetic studies are found pseudo-second-order (R2 > 0.999) and equilibrium data are fitted well by Freundlich isotherm model (R2 > 0.98). The calculated thermodynamic parameters exhibit that the adsorption processes of PNP on OVTs are physical and exothermic.

Hierarchically porous carbon derived from metal-organic frameworks for separation of aromatic pollutants

Porous carbon is the most important and most common adsorbent for the separation and treatment of organic pollutants. Characteristics such as accessible and large surface area, physical and chemical stability, and low-cost manufacturing method are desired for any adsorbent. Herein, a hierarchically porous carbon (HPC) was prepared by pyrolysis and graphitization of crystalline metal–organic frameworks (MOF-5) for enhanced adsorption of aromatic contaminants. The material treated at high temperature (950 °C) possesses large surface area (1512 m2/g), high porosity (0.94 cm3/g), and hierarchically porous structures. The generated mesopores around 4 nm improve the interconnectivity of micro- and macropores to make the porous material ideal for sorption of organic pollutants such as aromatic hydrocarbons. Effects of adsorbent dose, pH, ionic strength, contact time, and initial concentration on the adsorption of p-nitrophenol (PNP, as a model) were investigated. Adsorption isotherms and kinetics suggest that the adsorption is a spontaneous and endothermic physisorption process with monolayer surface coverage. The surface sites are electron-rich due to the graphitic layer, which has high affinity toward π electrons of the aromatic ring. The adsorption capacity of the hierarchically porous carbon (HPC) is nearly over 100% higher that of conventional activated carbon.

Adsorption of phenolic compounds onto calix[4]arene-bonded silica gels from aqueous solutions

This article describes the preparation of calix[4]arene-bonded silica gels (C[4]BS and DMC[4]BS), and their application to the removal of some selected phenolic compounds such as phenol (PHE), p-chlorophenol (PCP), m-nitrophenol (MNP) and p-nitrophenol (PNP) from aqueous solutions by adsorption method. In initial adsorption experiments appeared that C[4]BS was much more effective in adsorption of PNP rather than PHE, PCP and MNP, whereas DMC[4]BS exhibited too little adsorption ability towards all phenols. Herein, it was concluded that the hydrogen bonding capacities of both phenols and calix[4]arene based adsorbents played a predominant role in the interactions between adsorbate and adsorbent within the adsorption mechanism. Thus, in subsequent studies, the C[4]BS was employed as an adsorbent in the adsorption of PNP, and adsorption conditions were optimized. Furthermore, isotherm and kinetic studies were performed to clarify the phenomena of PNP adsorption onto C[4]BS.

Enhanced removal of p-nitrophenol from aqueous media by montmorillonite clay modified with a cationic surfactant

Montmorillonite clay (MC) yields after modification of the interlamellar spacing and the chemical character of its surface by treatment with cetyltrimethylammonium bromide (CTAB) a solid product (MCCTA). This has been used as an adsorbent for the removal of p-nitrophenol (PNP) from aqueous solutions. The MCCTA samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TG/DTA), FT-IR spectroscopy, zeta potential measurements, X-ray diffraction (XRD), and specific surface area. Investigations were also carried out to assess how the adsorption of PNP was affected by factors such as contact time, initial PNP concentration, adsorbent dosage and temperature. Of the two models tried the Freundlich isotherm gave a better account of the equilibrium data than did the Langmuir one. The kinetics could be successfully replicated by a pseudo-second order model with an activation energy of 55.0 kJ mol−1, while the thermodynamic parameters indicated an exothermic (ΔadsHo = −15.8 kJ mol−1), non-spontaneous (ΔadsGo = + 3.9–5.9 kJ mol−1) adsorption process. The experimental results showed MCCTA, unlike natural MC, to have a significant adsorption capacity for PNP removal from aqueous media.

Adsorptive removal of organics from aqueous phase by acid-activated coal fly ash: preparation, adsorption, and Fenton regenerative valorization of “spent” adsorbent

Raw coal fly ash was activated to an adsorbent by sulfuric acid impregnation. The activation condition, the adsorption capacity, and the regenerative valorization of the adsorbent were studied. The results show that the optimal preparation conditions of the adsorbent are [H2SO4] = 1molL-1, activation time = 30min, the ratio of coal fly ash to acid = 1:20 (g:mL), calcination temperature = 100°C. The adsorption of p-nitrophenol on the adsorbent accords with the pseudo-second-order kinetic equation and the adsorption rate constant is 0.089gmg-1min-1. The adsorption on this adsorbent can be considered enough after 35min, when the corresponding adsorption capacity is 1.07mgg-1 (85.6% of p-nitrophenol removal). Compared with raw coal fly ash, the adsorbent has a stable adsorption performance at low pH range (pH = 1-6) and the adsorption of p-nitrophenol is an exothermic process. Ninety minutes is required for the regenerative valorization of saturated adsorbent by Fenton process. The regenerative valorization for this saturated adsorbent can reach 89% under the optimal proposed conditions (30°C, pH = 3, [H2O2] = 5.0mmolL-1, [Fe2+] = 5.5mmolL-1). Within 15 experimental runs, the adsorbent has a better and better stability with the increase of experimental runs. Finally, the mechanism of activating coal fly ash is proposed, being verified by the results of the SEM and BET test.

Preparation of Starch-Hard Carbon Spherules from Ginkgo Seeds and Their Phenol-Adsorption Characteristics.

Carbon spherules from ginkgo seed starch were prepared through stabilization and carbonization processes. The ginkgo seed starch was first stabilized at 195 °C for 18 h, then carbonized at 500 °C for 2 h under an N2 atmosphere. The characterization results confirmed that carbon spherules were in the size range of 10–20 μm. Experimental data were also evaluated to find out the kinetic characteristics of phenols on the carbon spherules during the adsorption process. Adsorption processes for phenol, p-nitrophenol and p-chlorophenol were found to follow the pseudo-first order kinetic model with R2 values of 0.995, 0.997 and 0.998, while the rate constants k1 = 0.014, 0.009 and 0.011 min−1 showed that the adsorption is mainly controlled by adsorbate diffusion. The equilibrium data were analyzed with the Langmuir, Freundlich and Temkin–Pyzhev models and the best fit was observed with the Freundlich isotherm, suggesting the physical adsorption of phenols. From the thermodynamic functions, ∆G, ∆H, and ∆S were calculated, which showed that adsorption is more favorable at low temperature and is an exothermic process, and the adsorption of p-nitrophenol and p-chlorophenol were more advantageous than that of phenol.

Controllable synthesis of N-vinylimidazole-modified hyper-cross-linked resins and their efficient adsorption of p-nitrophenol and o-nitrophenol

A series of N-vinylimidazole-modified hyper-cross-linked resins was prepared, and the porosity and polarity of these resins were effectively tuned by altering the feeding amount of N-vinylimidazole in the polymerization. The results indicated that the Brunauer-Emmett-Teller surface area sharply decreased from 1258 to 74m2/g, the micropore area lowered from 494 to 0m2/g, the total pore volume greatly decreased from 1.14 to 0.49cm3/g, and the micropore volume rapidly reduced from 0.39 to 0cm3/g with increasing the feeding amount of N-vinylimidazole from 10% to 50% (mol/mol), and the pore size distribution showed a large population of pores in the microporous region extending to a higher part of mesoporous region. Meanwhile, the polarity of the resins obviously improved with increasing the feeding amount of N-vinylimidazole. The nitrogen content increased from 0.579% to 7.68% (w/w), and the contact angle decreased from 89.0° to 31.0°. The adsorption experiments indicated that these resins had large equilibrium capacities to p-nitrophenol and o-nitrophenol from aqueous solution, and they could be completely regenerated by a mixed solvent containing 80% (v/v) of ethanol and 0.01mol/L of NaOH aqueous solution.

Enhanced Adsorption of p-Nitrophenol from Aqueous Solutions Using a Functionalized Styrene-Divinylbenzene Copolymer

The effect of styrene-divinylbenzene copolymer functionalization by carboxylic acid groups on the adsorption of p-nitrophenol (p-NP) from aqueous solutions was investigated. The adsorption capacity of p-NP onto the functionalized copolymer (CP-F) was compared with that of the precursor copolymer, the chloromethylated styrene-divinylbenzene copolymer (CP-N). The two copolymers were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal analysis (DSC-TG), specific surface area and particle size measurements, pore size distribution, scanning electron microscopy (SEM), and elemental analysis (EDX). The adsorption of p-NP was substantially enhanced after the polymer functionalization, and it was demonstrated that hydrogen bonding is principally responsible for the high adsorption capacity of CP-F in comparison with CP-N. The adsorption kinetics of p-NP adsorption onto CP-F was well described by the pseudo-second-order model. From the four investigated isotherms, Langmuir, Freundlich, Redlich-Peterson, and Sips, the equilibrium data were better described by the Sips model. The maximum adsorption capacity of the CP-F polymer resulting from the Sips isotherm was 243.37 mg g−1. The capacity of regeneration and reuse of the CP-F polymer was evaluated in three consecutive cycles of adsorption-desorption.

Enhancement of p-nitrophenol adsorption capacity through N2-thermal-based treatment of activated carbons

In this work several activated carbons showing different textural and chemical properties were obtained by chemical and physical activation methods, using a lignocellulosic material (peach stones) as precursor. The activated carbon resulting from the chemical activation, namely as CAC, revealed the best textural properties (SBET=1521m2g−1, pore volume=0.90cm3g−1) and an acidic character. It was found that the activated carbon obtained at 300°C (under air atmosphere, PAC_air), and those synthesized at 750°C in presence of N2 flow with bubbling of water/12M H3PO4 solution (PAC_N2(H2O)/PAC_N2(H3PO4)), respectively, revealed worse textural properties, compared to CAC. Two functionalization treatments, by using sulphuric acid at boiling temperature (PACS) and nitric acid-urea-N2 heating at 800°C (PAC-NUT), were applied to PAC_air, in order to enhance the adsorption ability of the carbon material. Several techniques were carried out to characterize the physical and chemical properties of the obtained carbon materials. The modification treatments had influence on the carbon surface properties, since the nitric acid-urea-N2 heating treatment led to a carbon material with highly-improved properties (SBET=679m2g−1, pHIEP=5.3).Accordingly, the original and modified-carbon materials were tested as adsorbents to remove 4-nitrophenol (4-NP), assessing batch and fixed-bed column adsorption tests. PAC-NUT carbon offered the best adsorption behavior (qe=234mgg−1), showing a high ability for the removal of 4-NP from water.

Amides as a model system of low molar mass algal organic matter. Influence on the adsorption of p-nitrophenol on activated carbon

In this study, the adsorption equilibrium and diffusivity parameters of p-nitrophenol were estimated for water containing different concentrations of secondary amides. Commercial powdered activated carbon was used as an adsorbent. The external mass transfer coefficient (kf), the surface diffusion coefficient (Ds) and the standard free Gibbs energy were calculated for p-nitrophenol in the presence of different secondary amide concentrations. The analysis established that there are correlations between structural parameters of amides, on the one hand, and diffusion and thermodynamic parameters for p-nitrophenol adsorption process, on the other. It was noticed that voluminous hydrophobic amides decreased the adsorption capacity of p-nitrophenol on activated carbon. On the basis of the results obtained for external mass transfer coefficients, it is assumed that amides cause the reduction of adsorption capacity of p-nitrophenol onto activated carbon by concentrating at the solid/liquid interface.

Adsorption removal of o-nitrophenol and p-nitrophenol from wastewater by metal–organic framework Cr-BDC

In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o-nitrophenol (ONP) and p-nitrophenol (PNP) from aqueous solutions. Cr-BDC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and BET methods. The results indicate that Cr-BDC gets a very large specific surface area of 4128m2·g−1 and pore sizes are concentrated in 1nm, which is a benefit for using for wastewater treatment. The influences of the adsorption conditions, such as temperature, solution concentration, adsorption time and reusability on adsorption performance were investigated. Cr-BDC exhibited an encouraging uptake capacity of 310.0mg·g−1 for ONP, and adsorption capacity of Cr-BDC for ONP is significantly higher than that for PNP under suitable adsorption conditions. The characterizations of adsorption process were examined with the Lagergren pseudo-first-order, the pseudo-second-order kinetic model, and the intra-particular diffusion model. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. The results indicate that the as-prepared Cr-BDC is promising for use as an effective and economical adsorbent for ONP removal.

Luminescent Aggregated Copper Nanoclusters Nanoswitch Controlled by Hydrophobic Interaction for Real-Time Monitoring of Acid Phosphatase Activity.

A reversible luminescence nanoswitch through competitive hydrophobic interaction among copper nanoclusters, p-nitrophenol and α-cyclodextrin is established, and a reliable real-time luminescent assay for acid phosphatase (ACP) activity is developed on the basis of this luminescence nanoswitch. Stable and intensely luminescent copper nanoclusters (CuNCs) were synthesized via a green one-pot approach. The hydrophobic nature of CuNCs aggregate surface is identified, and further used to drive the adsorption of p-nitrophenol on the surface of CuNCs aggregate due to their hydrophobic interaction. This close contact switches off the luminescence of CuNCs aggregate through static quenching mechanism. However, the introduction of α-cyclodextrin switches on the luminescence since stronger host-guest interaction between α-cyclodextrin and p-nitrophenol causes the removal of p-nitrophenol from the surface of CuNCs. This nanoswitch in response to external stimulus p-nitrophenol or α-cyclodextrin can be run in a reversible way. Luminescence quenching by p-nitrophenol is further utilized to develop ACP assay using p-nitrophenyl phosphate ester as the substrate. Quantitative measurement of ACP level with a low detection limit of 1.3 U/L was achieved based on this specific detection strategy. This work reports a luminescence nanoswitch mediated by hydrophobic interaction, and provides a sensitive detection method for ACP level which is capable for practical detection in human serum and seminal plasma.

Synthesis and application of iron and zinc doped biochar for removal of p-nitrophenol in wastewater and assessment of the influence of co-existed Pb(II)

The modification of biochar as a low-cost adsorbent is essential to improve its surface properties and shows great potential in water decontamination. The iron and zinc doped sawdust biochar (Fe/Zn-biochar) with large apparent surface area (518.54m2/g) proposed in this work showed good performance for p-nitrophenol (PNP) removal compared with the pristine biochar (P-biochar), iron doped biochar (Fe-biochar) and zinc doped biochar (Zn-biochar) respectively. The batch experiments turned out that Fe/Zn-biochar exhibited larger PNP adsorption capacity under acidic pH solution, and the ionic strength had slightly negative impact on PNP adsorption. The adsorption kinetics and isotherms were discussed, and the experimental data fitted well the Pseudo-second-order equation and Langmuir model. The thermodynamic study indicated that the PNP adsorption was a spontaneous endothermic process. Furthermore, the simultaneous removal for PNP and Pb(II) by Fe/Zn-biochar was investigated. It implied that the adsorption of PNP and Pb(II) at their low concentration might be enhanced by the complexing-bridging mechanism of PNP and Pb(II) ascribing to the affinity between PNP and hydrophobic sites, in addition to the affinity between Pb(II) and oxygen-containing hydrophilic sites on Fe/Zn-biochar surface. However, the predominated competition between PNP and Pb(II) at their high concentrations with Fe/Zn-biochar suppressed their adsorption.

Amino-MIL-53(Al) sandwich-structure membranes for adsorption of p-nitrophenol from aqueous solutions

Novel sandwich PES-SPES/amino-MIL-53(Al)/PTFE adsorptive membranes were prepared by a filtration/immersion precipitation method and employed for the removal of p-nitrophenol (PNP) from water. The static adsorption thermodynamics, kinetics, dynamic adsorption/desorption and membrane reusability were investigated. The results showed that, amino-MIL-53(Al) displays very high saturation adsorption capacity towards PNP (297.85mgg−1). The sandwich membranes showed much higher adsorption performance (static adsorption capacity, breakthrough volume, saturation volume, dynamic adsorption capacity) and lower pressure drop than those of blank and mixed matrix membranes. With increased amino-MIL-53(Al) content, the maximum static adsorption capacity, saturation volume and dynamic adsorption capacity significantly increased. The sandwich membranes exhibited excellent reusability even after four recycles.

Exceptional Adsorption of Phenol and p-Nitrophenol from Water on Carbon Materials Prepared via Hydrothermal Carbonization of Corncob Residues

Phenol and p-nitrophenol (PNP) are priority pollutants widely present in wastewater. Developing superior or low-cost sorbents for their removal would be of great benefit. Here, corncob residues (CCR) were converted to hydrochars via hydrothermal carbonization (HTC) and further upgraded to carbon materials by thermal activation in an N2 atmosphere. The influence of HTC conditions including the temperature, residence time, and CCR/water weight ratio on the material properties and their performance for removing phenol and PNP from water were investigated and compared with those that were obtained from pyrochar (directly pyrolyzed CCR). Hydrochars showed lower adsorption capacities for phenols than pyrochar. The initial hydrothermal treatment at 220 °C and 2 h resulted in an improved porosity and 4- to 5-fold higher adsorption capacities for phenol and PNP compared with the pyrochar. However, hydrochars prepared at 250 °C or with a prolonged residence time (4 and 6 h) could not be upgraded to high performance carbon materials by thermal activation. The adsorption isotherms of both phenols on the best performance material were well correlated by the Sips model.

Mechanism and Surface Fractal Characteristics for the Adsorption of p-nitrophenol on Water-quenched Blast Furnace Slag

In the present study, the removal of p-nitrophenol (p-NP) from aqueous solution through the adsorption on water-quenched blast furnace slag (WBFS) was investigated. The physicochemical properties of the slag were characterized by SEM, XRD, FTIR and BET. Batch experiments were conducted to investigate the mechanism, kinetics and thermodynamics of adsorption process. The results showed that the experimental data could fit to Freundlich model. The enthalpy change (ΔH) and entropy change (ΔS) were 3.29 kJ·mol-1 and 4.66 J·(mol·K)-1, respectively. It indicated that the adsorption of p-NP on WBFS was an endothermic and entropy-increasing process. The values of ΔG decreased with increasing temperature, indicating the spontaneous adsorption proportional to the temperature. The adsorption could be divided into two parts, one was high-speed surface coverage, and the other was slow-speed internal diffusion adsorption. It was also found that the adsorption process followed the pseudo-second-order kinetic model. The fractal dimensions of WBFS surface calculated by Freundlich adsorption fractal model were 2.78, 2.80, 2.84 and 2.87 at different temperatures, respectively. It indicated the existence of fractal phenomenon with higher fractal dimension of WBFS at higher temperature.

Green reduction of oxidized graphite to reduced graphene oxide using Zygophyllum album L.f.: Comparative adsorption studies on p-nitrophenol

Successfully studies were developed to produce reduced graphene oxide by green reduction of graphene oxide using environmentally-friendly reducing agents. Here for the first time, we report the green reduction of oxidized graphite (OG) to reduced graphene oxide (RGO) using the green plant called Zygophyllum album L.f. (Z. album) which revealed strong reducing activity. Techniques of TEM, Raman, FTIR and BET were carried out for characterization of both samples. Comparative adsorption studies for the removal of p-nitrophenol (PNP) using OG and RGO from aqueous solution in batch mode were studied. Impacting parameters such as pH of solution, adsorbent dose, agitation time, initial concentration of PNP and temperature were estimated. Kinetic studies confirmed that pseudo-second-order kinetic model successfully represented the adsorption process. Batch adsorption isotherms were examined by Langmuir, Freundlich and Florry-Hugins adsorption isotherms. It was found that the experimental data fitted well with the Langmuir model. At different pHs, the isotherms and thermodynamics of adsorption process were also measured, showing that PNP adsorption capacity was significantly pH dependent and endothermic. Maximum adsorption capacities occurred at pH 4 (i.e., 333.3 and 500 mg PNP per gram of OG and RGO, respectively). Therefore, the prepared adsorbents of OG and RGO could be used as potential adsorbents for removing the p-nitrophenol from wastewater. Keywords: Adsorption of p-nitrophenol, Green reduction, Reduced graphene oxide, Zygophyllum album.

Morphology-Directed Catalysis with Branched Gold Nanoantennas

We synthesized multibranched gold nanoantennas (MGNs) of two morphologies by varying the core-to-branch ratio. We compared their efficacy in catalytic reduction of p-nitrophenol (PNP) to p-aminiphenol (PAP). We observed that MGNs with shorter protrusions had a faster induction time and higher apparent rate constant, kapp, for PNP catalysis relative to the MGNs with longer protrusions. By examining the reaction as a function of temperature, we observed significantly lower activation energy for the MGNs with shorter protrusions (80 J/g) compared to MGNs with longer protrusions (200 J/g). The Langmuir–Hinshelwood model was used to fit the change in kapp as a function of increasing [PNP], which demonstrated more efficient PNP adsorption on the surfaces of MGNs with shorter protrusions. For the MGNs with longer protrusions, PNP adsorption is affected by the heterogeneity of the surface sites resulting in a lower adsorption coefficient. We attributed the improved efficiency of the MGNs with shorter protrusions ...

Enhanced adsorptive removal of p-nitrophenol from water by aluminum metal-organic framework/reduced graphene oxide composite.

In this study, the composite of aluminum metal–organic framework MIL-68(Al) and reduced graphene oxide (MA/RG) was synthesized via a one–step solvothermal method, and their performances for p–nitrophenol (PNP) adsorption from aqueous solution were systematically investigated. The introduction of reduced graphene oxide (RG) into MIL-68(Al) (MA) significantly changes the morphologies of the MA and increases the surface area. The MA/RG-15% prepared at RG-to-MA mass ratio of 15% shows a PNP uptake rate 64% and 123% higher than MIL-68(Al) and reduced graphene oxide (RG), respectively. The hydrogen bond and π – π dispersion were considered to be the major driving force for the spontaneous and endothermic adsorption process for PNP removal. The adsorption kinetics, which was controlled by film–diffusion and intra–particle diffusion, was greatly influenced by solution pH, ionic strength, temperature and initial PNP concentration. The adsorption kinetics and isotherms can be well delineated using pseudo–second–order and Langmuir equations, respectively. The presence of phenol or isomeric nitrophenols in the solution had minimal influence on PNP adsorption by reusable MA/RG composite.