Enhanced Dye Adsorption and Bacterial Removal of Magnetic Nanoparticle-Functionalized Bacterial Cellulose Acetate Membranes

Utilizing biomass waste as a potential resource for cellulose production holds promise in mitigating environmental consequences.The current study aims to utilize pineapple biowaste extract in producing bacterial cellulose acetate-based membranes with magnetic nanoparticles(Fe_(3)O_(4)nanoparticles)through the fermentation and esterification process and explore its characteristics.The bacterial cellulose fibrillation used a high-pressure homogenization procedure,and membranes were developed incorporating 0.25,0.50,0.75,and 1.0 wt.%of Fe3O4 nanoparticles as magnetic nanoparticle for functionalization.The membrane characteristics were measured in terms of Scanning Electron Microscope,X-ray diffraction,Fourier Transform Infrared,Vibrating Sample Magnetometer,antibacterial activity,bacterial adhesion and dye adsorption studies.The results indicated that the surface morphology of membrane changes where the bacterial cellulose acetate surface looks rougher.The crystallinity index of membrane increased from 54.34%to 68.33%,and the functional groups analysis revealed that multiple peak shifts indicated alterations in membrane functional groups.Moreover,adding Fe_(3)O_(4)-NPs into membrane exhibits paramagnetic behavior,increases tensile strength to 73%,enhances activity against E.coli and S.aureus,and is successful in removing bacteria from wastewater of the river to 67.4%and increases adsorption for anionic dyes like Congo Red and Acid Orange.

High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption:Optimization and mechanism study

In this study,an alternative precursor for production of activated carbon was introduced using dragon fruit(Hylocereus costaricensis)peel(DFP).Moreover,KOH was used as a chemical activator in the thermal carbonization process to convert DFP into activated carbon(DFPAC).In order to accomplish this research,several approaches were employed to examine the elemental composition,surface properties,amorphous and crystalline nature,essential active group,and surface morphology of the DFPAC.The BrunauerEmmettTeller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m2g 1.The cationic dye Methylene Blue(MB)was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution.The effects of adsorption input factors(e.g.DFPAC dose(A:0.040.12 g L 1),pH(B:310),and temperature(C:3050℃))were investigated and optimized using statistical analysis(i.e.BoxBehnken design(BBD)).The adsorption kinetic model can be best categorized as the pseudofirst order(PFO).Whereas,the adsorption isotherm model can be best described by Langmuir model,with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg g 1 at 50℃.The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction,pp interaction,and Hbonding.Finally,the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes(e.g.MB).

Photo-Grafting Copolymerization of PP Nonwoven Fabric and Its Application for Acidic Dye Adsorption and Filtration

The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.

Recyclable hydrolyzed polymers of intrinsic microporosity-1/Fe_(3)O_(4) magnetic composites as adsorbents for selective cationic dye adsorption

Polymers of intrinsic microporosity shows great potential for dye adsorption and magnetic Fe_(3)O_(4) are easy to be separated.In this work,hydrolyzed polymers of intrinsic microporosity-1/Fe_(3)O_(4) composite adsorbents were prepared by phase inversion and hydrolysis process for cationic dye adsorption.The chemical structure and morphology of the composite adsorbents were systematically characterized by several characterization methods.Using methylene blue as the target dye,the influences of solution pH,contact time,initial dye concentration,and system temperature on the methylene blue adsorption process were investigated.The incorporation of Fe_(3)O_(4) particle into hydrolyzed polymers of intrinsic microporosity-1 endow the adsorbent with high magnetic saturation(20.7 emu·g^(–1))which allows the rapid separation of the adsorbent.Furthermore,the adsorption process was simulated by adsorption kinetics,isotherms and thermodynamics to gain insight onto the intrinsic adsorption mechanism.In addition,the composite adsorbents are able to selectively adsorb cationic dyes from mixed dyes solution.Hydrolyzed polymers of intrinsic microporosity/Fe_(3)O_(4) shows only a slight decrease for methylene blue adsorption after 10 adsorption/regeneration cycles,demonstrating the outstanding regeneration performance.The high adsorption capacity,outstanding regeneration ability,together with simple preparation method,endow the composite adsorbents great potential for selective removal of cationic dyes in wastewater system.

Ultra-high specific surface area activated carbon from Taihu cyanobacteria via KOH activation for enhanced methylene blue adsorption

Cyanobacteria-based activated carbon(CBAC)was successfully prepared by pyrolysis-activation of Taihu cyanobacteria.When the impregnation ratio and activated temperature were 2 and 800-C,respectively,the optimal CBACs possessed an ultra-high specific surface(2178.90 m^(2)·g^(-1))and plenty of micro-and meso-pores,as well as a high pore volume(1.01 cm^(3)·g^(-1)).Ascribed to ultra-high surface area,π-π interaction,electrostatic interaction,as well as hydrogen-bonding interactions,the CBACs displayed huge superiority in efficient dye removal.The saturated methylene blue adsorption capacity by CBACs could be as high as 1143.4 mg·g^(-1),superior to that of other reported biomass-activated carbons.The adsorption was endothermic and modeled well by the pseudo-second-order kinetic,intra-particle diffusion,and Langmuir models.This work presented the effectiveness of Taihu cyanobacteria adsorbent ascribed to its super large specific surface area and high adsorption ability.

Single and Binary Dye Adsorption of Methylene Blue and Methyl Orange in Alcohol Aqueous Solution via Rice Husk Based Activated Carbon:Kinetics and Equilibrium Studies

The present work was mainly focused on the single and binary adsorption of methylene blue(MB)and methyl orange(MO)from alcohol aqueous solution over rice husk based activated carbon(RHAC).The study of single dye adsorption equilibrium experiments found that the Langmuir adsorption model was consistent with the adsorption behavior of RHAC on MB and MO,indicating that it was a single layer adsorption.The adsorption behavior con-formed to the pscudo-second-order kinetic model.The binary dye adsorption experiments showed that the Lang-muir-Freundlich model could be applied to describe the adsorption behavior of RHAC on MB and MO.Comparation with the single dye system,the adsorption capacity on the binary dye system was larger,and there was"competitive adsorption"and"synergistic adsorption"effects existed.Meanwhile,the pseudo-second-order kinetic model also fit for the binary dye adsorption behavior.

Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions

Humic acid-immobilized amine modified polyacrylamide/bentonite composite （HA-Am-PAA-B） was prepared and used as an adsorbent for the adsorption of cationic dyes （Malachite Green （MG）, Methylene Blue （MB） and Crystal Violet （CV）） from aqueous solutions. The polyacrylamide/bentonite composite （PAA-B） was prepared by intercalative polymerization of acrylamide with Nabentonite in the presence of N,N＇-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0-8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order： MG〉MB〉CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch （SRS） （multicomponent Freundlich type） equation.

Tough Poly(L-DOPA)-containing Double Network Hydrogel Beads with High Capacity of Dye Adsorption

Developing a low-cost and well-recyclable adsorbent with high adsorption capacity is greatly desirable in dye wastewater treatment. Here, we demonstrate a kind of novel tough and reusable hydrogel beads with quite high capacity of dye adsorption via incorporating mussel-bioinspired poly（L-DOPA） （PDOPA） into alginate/poly（acrylamide） double network （DN） hydrogels. The synthesized PDOPA nanoaggregates were introduced into the DN hydrogels by simple one-pot mixing with the monomers prior to polymerization. The fabricated hydrogel beads exhibited high mechanical strength and good elastic recovery due to the interpenetrating Ca2＋-alginate and poly（acrylamide） networks. It was shown that the beads exhibited relatively high dye adsorption capacity compared to other adsorbents reported in literature, and the introduction of PDOPA with an appropriate amount raised the adsorption capacity. It is believed that the addition of PDOPA and the matrix of double network architecture contributed synergistically to the high adsorption capacity of hydrogel beads. Moreover, the desorption of dyes could be easily realized via rinsing in acidic water and ethanol solution. The hydrogel beads remained the high adsorption capacity even after 5 times of adsorption and desorption cycles. This tough and stable hydrogel with high adsorption capacity may have potential in treatment of dye wastewater released by textile dyeing industry.

A Multifunctional {P_(2)Mo_(5)}-based Hybrid Applying to Catalysis, Electrocatalysis and Dye Adsorption

As a common environmental pollutant, thioether can cause serious environmental pollution, so selective oxidation of thioether has become one of the current research hotspots. In this paper, an inorganic-organic hybrid based on a Standberg-type polyoxometalate, [Hbiz]_(5)[HP_(2)Mo_(5)O_(23)]·5H_(2)O(1)(biz=benzimidazole), was obtained by adjusting pH under hydrothermal conditions. The structure was characterized by infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound 1 can be used as an excellent catalyst for the oxidation of thioanisole. The experimental results showed that thioanisole could be catalytically oxidized to methyl phenyl sulfoxide by compound 1 as a catalyst within 40 min. The conversion rate and selectivity reached 99%. Compound 1 had good cycling stability as a heterogeneous catalyst. In addition, the electrocatalytic reduction of H_(2)O_(2) and Cr_(2)O_(7)^(2−) for hybrid 1 was preliminarily investigated. In addition, the adsorption performance of hybrid 1 on cationic dye crystal violet and methylene blue was tested, and the adsorption efficiencies can reach 98.5% and 86.3%, respectively.

Thiacalix[4]arene 1,2,3-triazole-polyethylene glycol polymers:Synthesis and dye adsorption properties

By reacting alkynylthiacalix[4]arenes with polyethylene glycol azido compounds,a series of novel thiacalix[4]arene 1,2,3-triazole-polyethylene glycol netty polymers were conveniently prepared in good yields.Their structures and morphologies were studied by ^1H NMR,IR.and elemental analysis and SEM images.On average,approximately 28-31 thiacalixarene units exist in each polymeric molecule.These novel polymers possess excellent adsorption ability for both cationic and anionic dyes.The saturation adsorption capacity for Congo red reached 1.3-1.4 mmol/g.They exhibit high and stable adsorption ability in the scope of pH 5-9,and maintain good properties in five cycles.

Rapid formation of metal-monophenolic networks on polymer membranes for oil/water separation and dye adsorption

Surface deposition based on metal-phenolic networks(MPNs) has received increasing interest in recent years. The catechol structure is generally considered to be essential to the formation of MPNs. Our most recent results have demonstrated that some kinds of monophenols can form MPNs on substrate surfaces.Herein, we report a fast and effective surface-coating system based on the coordination of 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid, a kind of monophenol, with Fe^(3+). Compared with other metal ions such as Cu^(2+)and Ni^(2+), Fe^(3+)with stronger electron acceptability can coordinate with the monophenol more strongly to form MPNs, and moreover, the deposition time significantly decreases to 40 min from generally 24 h. It is demonstrated that the deposition process is controlled by the coordination, Fe^(3+)hydrolysis, and deprotonation of the monophenol. The coatings endow substrates such as polypropylene microfiltration membrane with underwater superoleophobicity, which can be applied in oil/water separation with high separation efficiency and great long-term stability. In addition, the coated membranes are positively charged and thus are useful in selective adsorption of dyes. The present work not only provides a novel, fast, and one-step deposition method to fabricate MPNs, but also demonstrates that the fabrication efficiency of monophenol-based MPNs is comparable with that of polyphenol-based MPNs.

ADSORPTION OF DYES ON ACTIVATED CARBON FIBERS

The adsorplion behavior of dyes on a variety of sisal based activated carbonfibers (SACF) has been studied in this paper The results show that this kind of ACFhas excellent adsorption capacities for some organic (dye) molecules. SACF canremove nearly all methylene blue, crystal violet, bromophenol blue and Eriochromeblue black R from water after static adsorption for 24 h. at 30℃ The adsorptionamounts can reach more than 400 mg/g when adding 50 mg SACF into 50 ml dyesolution. Under the same conditions, the absorption amounts of xylenol orangefluorescein and Eriochrome black T were lower On the other hand, the adsorptionamounts change along with the characteristics of adsorbents. The SACFs activatedabove 840 ℃ which have higher specific surface areas and wider pore radii, havehigher adsorption amounts for the dyes. The researching results also show that foeadsorption rates of dyes onto SACFs decrease by the order of methylene blue,Eriochrome blue black R and crystal violet.

Green synthesis of nickel nanoparticles using Ocimum sanctum and their application in dye and pollutant adsorption

Nickel nanoparticles as an eco-friendly adsorbent was biosynthesized using Ocimum sanctum leaf extract. The physiochemical properties of green synthesized nickel nanoparticles(Ni Gs) were characterized by UV–Vis spectroscopy(UV–Vis), Fourier Transform Infrared Spectroscopy(FTIR), X-ray diffraction(XRD), Scanning Electron Microscope(SEM) and Transmission Electron Microscope(TEM). Ni Gs were used as adsorbent for the removal of dyes such as crystal violet(CV), eosin Y(EY), orange II(OR) and anionic pollutant nitrate(NO3-), sulfate(SO42-) from aqueous solution. Adsorption capacity of Ni Gs was examined in batch modes at different p H, contact time, Ni G dosage, initial dye and pollutant concentration. The adsorption process was p H dependent and the adsorption capacity increased with increase in contact time and with that of Ni G dosage, whereas the adsorption capacity decreased at higher concentrations of dyes and pollutants. Maximum percentage removal of dyes and pollutants were observed at 40, 20,30, 10 and 10 mg·L-1initial concentration of CV, EY, OR, NO3-and SO42-respectively. The maximum adsorption capacities in Langmuir isotherm were found to be 0.454, 0.615, 0.273, 0.795 and 0.645 mg·g-1at p H 8, 3, 3, 7and 7 for CV, EY, OR, NO3-and SO42-respectively. The higher coef ficients of correlation in Langmuir isotherm suggested monolayer adsorption. The mean energies(E), 2.23, 3.53, 2.50, 5.00 and 3.16 k J·mol-1for CV, EY, OR, NO3-and SO42-respectively, calculated from the Dubinin–Radushkevich isotherm showed physical adsorption of adsorbate onto Ni Gs. Adsorption kinetics data was better fitted to pseudo-second-order kinetics with R2 N 0.870 for all dyes and pollutants. Ni Gs were found to be an effective adsorbent for the removal of dyes and pollutants from aqueous solution and can be applied to treat textile and tannery ef fluents.

Synthesis and characterization of carboxymethyl cellulose/organic montmorillonite nanocomposites and its adsorption behavior for Congo Red dye

A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared （FT-IR） spectrophotometer, X-ray diffraction （XRD） method, transmission electron microscope （TEM）, scanning electron microscope （SEM）, and thermal gravimetric （TG） analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red （CR） dye were investigated by controlling the amount ofhexadecyl trimethyl ammonium bromide （CTAB）, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 rag/g, with the amount of CTAB being 1.0 cation exchange capacity （CEC） of MMT, the weight ratio of CMC to OMMT being l：l, the reaction time being 6 h, and the reaction temperature being 60~C. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.

The adsorptive properties of UiO-66 towards organic dyes: A record adsorption capacity for the anionic dye Alizarin Red S.

In order to decisively determine the adsorption selectivity of zirconium MOF(UiO-66) towards anionic versus cationic species, the adsorptive removal of the anionic dyes(Alizarin Red S.(ARS), Eosin(E), Fuchsin Acid(FA)and Methyl Orange(MO)) and the cationic dyes(Neutral Red(NR), Fuchsin Basic(FB), Methylene Blue(MB),and Safranine T(ST)) has been evaluated. The results clearly reveal a significant selectivity towards anionic dyes. Such an observation agrees with a plethora of reports of UiO-66 superior affinity towards other anionic species(Floride, PO_4^(3-), Diclofenac sodium, Methylchlorophenoxy-propionic acid, Phenols, CrO_4^(2-), SeO_3^(2-), and AsO_4^-). The adsorption process of ARS as an example has been optimized using the central composite design(CCD). The resultant statistical model indicates a crucial effect of both pH and sorbent mass. The optimum conditions were determined to be initial dye concentration 11.82 mg.L^(-1), adsorbent amount 0.0248 g, shaking time of 36 min and pH 2. The adsorption process proceeds via pseudo-second order kinetics(R^2= 0.999). The equilibrium data were fit to Langmuir and Tempkin models(R^2= 0.999 and 0.997 respectively). The results reveal an exceptional removal for the anionic dye(Alizarin Red S.) with a record adsorption capacity of400 mg·g^(-1). The significantly high adsorption capacity of UiO-66 towards ARS adds further evidence to the recently reported exceptional performance of MOFs in pollutants removal from water.

Adsorption mechanism of expanded graphite for oil and dyes

Expanded graphite （r-;G） shows higher adsorption capacity for oils than for dyes. To illustrate the different adsorption mechanism of EG for these pollutants, adsorption capacities of dyes and oil on EG were firstly studied. And then stepwise adsorption for oils was carried out with EG which has been saturated firstly by dyes, the difference between adsorbance of oil on EG was checked with deviation analysis. Scanning electronic microscopy （SEM） analysis was used to show structure difference of EG adsorbed different adsorbates. These used adsorbates were SD300 oil, basic fuchsine, Auramine lake yellow O and acid brilliant red 3B. The adsorption isotherm of dyes on EG is type 11 or type 1, and their equilibrium adsorbances are less than 1.0 g/g. While, adsorbance for SD300 oil can reach 104.5 g/g. Deviation analysis for stepwise adsorbances of oil shows no statistical significance. EG saturated firstly by dyes, still has an average adsorption capacity of 35 g/g for SD300 oil, and it does not change with the initial dyes concentration. SEM photos illustrate the adsorption of oil on EG is mainly filling, In the adsorption of dyes, there is severe breakage of the V-type pore and shrinkage of the particle. Kinetic difference is analyzed also.

Adsorption of Methylene Blue on magnesium silicate: Kinetics, equilibria and comparison with other adsorbents

Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate （Florisil） of three particle size ranges （mean diameters of 112, 200 and 425 μm） was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye.

Preparation and Properties of Polyacrylamide/Sodium Alginate Hydrogel and the Effect of Fe^(3+)Adsorption on Its Mechanical Performance

The preparation and application of functional hydrogels based on natural polysaccharides have always been a hot research topic.In this study,using acrylamide(AM)monomer,N,N'-methylene bisacrylamide(MBA)as crosslinking agent,potassium persulfate(K2S2O8)as initiator,in the presence of natural polysaccharide sodium alginate(SA),the PAM/SA hydrogel was prepared by free radical polymerization.Fourier transform infrared spectroscopy(FT-IR),swelling performance tests,scanning electron microscope(SEM),thermogravimetric analysis(TGA),UV-visible spectrophotometer,mechanical property measurements were carried out to analyze the composition,morphology,and performance of the hydrogels.The swelling behavior,dye adsorption performance,and the mechanical properties of PAM/SA hydrogels before and after Fe^(3+)adsorption were studied.The experimental results showed that the introduction of SA with 4.7%,7.8%,and 10.3%effectively improved the mechanical and dye adsorption properties of PAM composite hydrogels.The adsorption capacity of PAM/4.7%SA and PAM/10.3%SA hydrogels at equilibrium can reach 40.01 and 44.02 mg/g for methylene blue,which is higher than the value 13.58 mg/g of pure PAM hydrogel.The compressive strength of pure PAM hydrogel is 0.124 MPa.When the SA content is 4.7%,7.8%,and 10.3%,the compressive strength of the PAM/SA hydrogel was corresponding to 0.130 MPa,0.134 MPa,and 0.152 MPa,respectively.Fe^(3+)was introduced into the PAM/SA hydrogels,and PAM/SA/Fe^(3+)double-network hydrogels with excellent mechanical properties could be prepared by adjusting the SA content(4.7%,7.8%,and 10.3%),soaking time(1 h,2 h,3 h,4 h,5 h,6 h),and Fe^(3+)concentration(4.76%,7.41%,9.09%,and 13.04%).Under the same Fe^(3+)concentration of 9.09%and adsorption time of 4 h,the compressive strengths of the PAM/4.7%SA,PAM/7.8%SA,and PAM/10.3%SA hydrogels could reach 0.354 MPa,0.767 MPa,and 0.778 MPa,respectively.

Assessment of Sericin Biosorbent for Selective Dye Removal

The silk sericin is the main residue in silk production and it is found to be a low cost and efficient bio-sorbent. In this study, sericin was characterized with various techniques including SEM （scanning electron micro- scope）, XRD, N2 physisorption, FTIR （Fourier transformed infrared spectroscopy） and XPS （X-ray photoelectron spectroscopy）. The nitrogen content of sericin was ca. 8.5 mmol.g-1 according to elemental analysis. Dye adsorption by sericin biosorbent was investigated with the acid yellow （AY）, methylene blue （MB） and copper （II） phthalocyanine-3,4＇4＂4＇＂-tetrasulfonic acid （CuPc） dyes from water. Sericin displayed large capacity for AY andCuPc adsorption with adsorption capacities of respectively 3.1 and 0.35 mmol.g-1, but it did not adsorbed methyl- ene blue dye. This selectivity is due to the basicity of amide groups in seriein biosorbents.

Synthesis of activated carbons from black sapote seeds,characterization and application in the elimination of heavy metals and textile dyes

Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(black sapote seeds) as a raw material for its synthesis. These carbons were chemically activated using phosphoric acid and carbonized at 673 and 873 K. Adsorption isotherms were constructed for the textile dyes on the carbons, and this data was treated using Langmuir’s equation to quantitatively describe the adsorption process. The synthesized carbons were characterized using FTIR, EA, SEM, Nitrogen adsorption(specific surface areas of 879 and 652 m2·g-1), and their points of zero charge(2.1 and 2.3). It was possible to adsorb both heavy metals and textile dyes present in aqueous solutions and wastewaters using these activated carbons. Heavy metals were adsorbed almost completely by both carbons. Cationic dyes where adsorbed(58–59.8 mg·g-1) in greater amounts compared to anionic dyes(10–58.8 mg·g-1). The amount of anionic dyes adsorbed increased almost 30% by changing the pH of the solutions. One of the carbons was thermally regenerated on three occasions without losing its adsorption capacity and it was proved in a flow system.