Adsorbent For Wastewater Treatment Research Articles

Keratin as a sustainable biopolymer for waste water treatment

Keratin is one of the most abundant natural polymers with potential application in various fields but is usually seen discarded as waste generated from poultry farms along roadsides and landfills. These are indeed the cheapest source of keratin protein which could be used for various applications. Owing to the structural properties, keratinous materials are now being exploited in wastewater treatment systems as adsorbents. The rich amino acid content having hydroxyl, carboxyl and amino groups has been found to be beneficial in removing contaminants from waste waters like heavy metals and dyes. Research based on this idea has received peak attention to a point where formulations of different adsorbent materials like nanofibre, biofilms and biocomposite from keratinous raw materials are now available for commercial use. This review summarises the application of keratin as an efficient adsorbent for waste water treatment providing an insight into its structure, forms of keratin used for treatments and mechanism of adsorption of different components in waste water.

TiO2 Nanoparticles as Bifunctional Adsorbent/Photocatalyst for Degradation of Effluent from Local Dairy in Telangana

Contamination of precious life sources with industrial waste including dairy effluent is an increasing concern worldwide. Over the past few years, titanium dioxide nanoparticles have drawn worldwide attention as an efficient photocatalyst and adsorbent for wastewater treatment. The current study refers to the potential of nitrogen doped titanium dioxide nanoparticles as an adsorbent and photocatalyst to purify wastewater from the local dairy to meet the quality of wastewater discharged into public sewers. The Nitrogen doped titanium dioxide (TiO2) Nano Materials were prepared by sol-gel technique and calcined at various temperatures. Characterization techniques such as SEM, XRD and FTIR were performed and Zeta potential was estimated. Efficiency of degradation as applied to dairy effluent has been examined varying the parameters such as time of exposure and dose of nanoparticles along with solution pH variation monitored during study. A good reduction in COD of about 99 % was observed after treatment under visible light. It is observed that calcining temperature affects activity of TiO2 nano particles. Furthermore, statistical analysis that represent experimental response as a function of independent parameters as well as analyse the interaction between the parameters was successfully employed. The results showed that TiO2 nanoparticles can be employed as adsorbents for the treatment of dairy waste water. Keywords: Adsorbent, Chemical oxygen demand, Dairy effluent, Doping, nanoparticles, TiO2

Cellulose-based thermosensitive supramolecular hydrogel for phenol removal from polluted water

Pollution of phenolic effluent from spice and plastics factories has become increasingly serious. Thus, developing a green and highly efficient adsorbent to remove phenolic compounds from wastewater is of urgent need. In this study, cellulose graft copolymer was synthesized through grafting 4-vinylpyridine monomer and polyethylene glycol methacrylate to a molecular skeleton of cellulose by free radical polymerization. The supramolecular hydrogel was successfully synthesized by physical cross-linking of cellulose graft copolymer and α-cyclodextrin. These supramolecular hydrogels were thoroughly characterized and the adsorption performance (adsorption isotherms and adsorption kinetics) of phenol on the supramolecular hydrogel were investigated in batch operation. The supramolecular hydrogel not only exhibited excellent adsorption of phenol, but also demonstrated increased mechanical strength due to the introduction of a modified cellulose base material. The adsorption kinetics of phenol on the supramolecular hydrogel followed a quasi-second-order reaction, with a correlation coefficient of 0.9909. The adsorption isotherm conformed to the Langmuir adsorption isotherm, and the maximum adsorption capacity of phenol can reach 80.71 mg g−1, which was 2–3 times higher than traditional carbon-based materials. The results demonstrate the great promise of the waste-derived supramolecular hydrogel to be used as an efficient adsorbent in wastewater treatment.

Studies of Adsorption Capacity of Montmorillonite-Enriched Clay from the Khmelnytskyi Region

Clay from the Khmelnytskyi region was enriched in montmorillonite by separation of a fraction with a particle size  0.5 ∙ 10-6 m. The X-ray diffraction and thermal analyses suggest that the enriched clay composition is close to mono-mineral, that is, represented by ferric-type montmorillonite in the form of Ca and Mg. The mineral interlayer spacings are partially filled with natural organic matter. An exchange capacity of montmorillonite is 0.78 mmol/g as shown by the photocolorimetry studies of the adsorption of the cationic methylene blue (MB) dye. It is recommended that studied clay be used as an effective natural adsorbent for wastewater treatment and for the arrangement of geochemical barriers to prevent harmful substances from entering the environment.

Novel co-polymerization of polypyrrole/polyaniline on ferrate modified biochar composites for the efficient adsorption of hexavalent chromium in water

It is still a huge challenge to prepare cheap and effective composite materials for removing hexavalent chromium (Cr(VI)) in sewage treatment. In this study, a noval co-polymerization of polypyrrole/polyaniline on ferrate modified biochar (Ppy/PANI/FBC) was fabricated via ferrate-promoted pyrolysis and in-situ oxidative polymerization of pyrrole and aniline molecules to effectively remove Cr(VI) from polluted water. The Ppy/PANI/FBC quickly decreased Cr(VI) concentration from 38.92 to 3.92 mg/L within 400 min, with an efficient removal efficiency (89.92%), which was significantly higher than that of FBC (4.75%), Ppy/FBC (72.30%), and PANI/FBC (42.43%). These results are mainly caused by its conjugated connection and well-dispersion of Ppy and PANI on the surface of a carbon-based material. Meanwhile, the experimental results were in line with the pseudo-second-order kinetic and Freundlich models. The Ppy/PANI/FBC is featured by a high capacity of Cr(VI) adsorption (up to 203.71 mg/g). In addition, it could be adopted for efficiently removing Cr(VI) over a wide pH range (4–9) because of the positively charged nitrogen (–NH.+– and = N+–). The sorption mechanisms of Cr(VI) were identified, including electrostatic interaction with surface protonated nitrogen (N+), ion exchange between the doped Cl− ions and Cr(VI), chemical decrease of the Cr(VI) to Cr(III) by the iron valence cycle and efficient electron transfer of Ppy/PANI/FBC, as well as surface complexation by amine and oxygen-containing groups. More importantly, 97.98% Cr(VI) was efficiently removed in 20 min by coupling a photocatalytic reaction, also providing a novel idea for the practical use of adsorbents in wastewater treatment.

Statistical optimization of Methylene Blue dye removal from a synthetic textile wastewater using indigenous adsorbents

This study was carried out to determine the most suitable indigenous adsorbents to remove Methylene Blue (MB) dye from aqueous solution and to statistically optimize the removal process parameters. Experiments were performed to investigate the adsorption capacities of indigenous bio-adsorbents such as charcoal, banana leaves ash (BLA), coconut coal, neem seed and rice husk ash to remove dye from industrial effluent. The dye removal process parameters were optimized using the One-Factor-at-a-Time (OFAT) method and statistically using central composite design (CCD). Banana leaves ash with particle sizes of 0.053–0.075 mm was found to be a potential adsorbent for dye removal. Among six parameters pH, incubation temperature and particle size were fixed at 8.7 (without control), 30 ± 0.5 °C (ambient) and 0.053–0.075 mm, respectively from the experimental results using the OFAT method. The other three parameters, adsorbent dose, shaking time and shaking speed were finally optimized statistically. The highest removal of MB (93.75%) was obtained through the statistical experimental design at optimum conditions of 23.9 mg/100 ml adsorbent (BLA) dose, 3 h shaking time and 356 rpm shaking speed. The ANOVA showed that the developed model is highly significant with an R 2 value of 0.99. All model terms are also highly significant (p-value<0.01, except for the interactive terms ‘adsorbent dose’ and ‘shaking time’ (p-value<0.05) (also significance at 5% confidence level). The validation experiment demonstrated great similarity between predicted and experimental results. The study indicates that BLA could be employed as a low-cost alternative adsorbent in wastewater treatment to remove dyes.

Preparation of humic acid-bentonite polymer composite: A heavy metal ion adsorbent

Adsorbents for wastewater treatment have evolved from scientific adsorbents to natural adsorbents. In this study, a humic acid-bentonite polymer (HBP) composite comprising humic acid, bentonite, and anionic polyacrylamide was integrated into an anionic polyacrylamide (aPAM) polymer matrix as an adsorbent pellet with N, N-methylene-bis-acrylamide (MBA), sodium tetraborate pentahydrate and chromium chloride is used as a novel adsorbent to remove Ni2+, Cd2+ and Pb2+ ions from aqueous solution. Sorption of these ions onto HBP is studied as a function of pH, adsorbent dosage, initial metal ion concentration, humic acid, and bentonite properties to evaluate adsorption efficiency. The results showed that adsorption sharply depends on pH, metal ion concentration, and contact time, but is complemented by humic acid and bentonite properties. The adsorption increased from 8% to 94.7% in the first 30 min at respective pH values of 5.6 and 9 for (Ni2+, Cd2+, and Pb2+). The HBP sorption power decreased with increasing adsorbent dosage, while the adsorption efficiency increased in ascending order for the cations Pb2+, Ni2+ and Cd2+ with efficiencies up to 94.7%, 90.9%, and 90.2%. The experimental data for Ni2+, Pb2+ adsorption fits the Langmuir isotherm, while that for Cd2+ adsorption fits the Freundlich isotherm. HBP showed modest adsorption performance at low and high concentrations, this is attributed in large part to the humic acid and bentonite properties that affect HBP's unique performance.

Highly effective adsorption of organic dyes from aqueous solutions on longan seed-derived activated carbon

In this study, longan seeds - an agricultural by-product was used to fabricate activated carbon (LSAC) through two-step pyrolysis with pre-carbonization at low temperature in the first step and then activation by H3PO4. LSAC with large surface area and porous structure exhibits an excellent capacity of absorption towards both cationic dyes (methylene blue (MB), rhodamine-B (RhB)) and anionic dyes (methyl orange (MO), congo red (CR)). Experimental data can be described well by the pseudo-second kinetic model. The maximum adsorption capacity based on Langmuir isotherm model was found as 502.84; 397.77; 464.66 and 350.64 mg.g−1 for MB, RhB, MO and CR, respectively. The adsorption of MB, RhB and CR on LSAC is spontaneous and endothermic, while that for MO is spontaneous but exothermic. Furthermore, the adsorption mechanism of dyes on LSAC was also studied showing that it can occur by electrostatic interaction, hydrogen bonding, the filling of pores involving the interaction between dye ions with specific functional groups such as −OH, −COOH, −NH2 and −PO43- on the LSAC surface. These results suggest that LSAC material may be envisaged as a promising adsorbent for treatment of wastewater in textile industries.

Enhanced Macroporous Cationic Chitosan Hydrogel by Freezing and Thawing Method with Superadsorption Capacity for Anionic Dyes

In this study, we have developed a simple technique to prepare cationic chitosan hydrogel with interconnected porous structure using freeze–thaw process and the obtained hydrogel was named FCS hydrogel. Scanning electron microscopy (SEM) imaging discovered that the synthesized hydrogel demonstrated interconnected porous structure in the scope of 5–20 μm. We also showed that the FCS hydrogel exhibits pH responsiveness behavior, and demonstrated reversible swelling and de-swelling behaviors maintaining their mechanical stability. We demonstrate that the FCS hydrogel swelling capacity decreased at alkaline pH and rose with a decline in pH value. Besides, the FCS hydrogel presented specific surface area of 78.25 ± 8.75 m2 g−1, due to the cryogenic treatment of glutaraldehyde cross-linked chitosan hydrogel could increase the surface area and permeability of composite hydrogel and then strongly increasing the adsorption capacity. Subsequently, the FCS monolithic hydrogel tested dyes removal, which provides a high removal efficiency towards anionic dyes including congo red (CR) and sodium fluorescein (SFL) dyes. Significantly, we show that the FCS hydrogel could be regenerated and reused as an adsorbent for wastewater treatment without significant loss of pollutants removal efficiency over a number of adsorption and washing cycles. This study offers a promising environmental friendly and sustainable interconnected porous hydrogel for anionic dye removal from wastewater.

Review on some metal oxide nanoparticles as effective adsorbent in wastewater treatment.

Water contamination has turned into one of the most serious issues in the world. Nanomaterials are proficient to carry away heavy metals, organic and inorganic dyes, pesticides, and small molecules from polluted water. In this regard, nanoparticles have gained much attention due to their extraordinary properties compared to bulk materials. Metal oxide nanoparticles and nanocomposites have several advantages such as elevated surface area, low concentration, easily separable after treatment and so on. Among many feasible techniques, the adsorption process is one of the most useful techniques for removing heavy ions and dyes from wastewater and has gained much attention from researchers. Several studies on metal oxide nanoparticles and their use in wastewater treatment have been published in the literature. This chapter gives an outline about five metal oxide based nanomaterials and nanocomposites as well as their applications in water pollution removal where the efficiency, limits and favourable circumstances are compared and explored. This article surely helps to gather information about some metal oxide nanoparticles and nanocomposites in wastewater treatment by the adsorption technique. In this review article, we primarily focused on five metal oxide nanoparticles and some of their recent applications published in the last two years.

Wastewater Treatment by Polymeric Microspheres: A Review.

This review addresses polymer microspheres used as adsorbent for wastewater treatment. The removal of various pollutants (including dyes, heavy metal ions, and organic pollutants) is a prominent issue, as they can cause severe health problems. Porous microspheres can provide large specific area and active sites for adsorption or photo degradation. Enhancement in performance is achieved by various modifications, such as the introduction of nanoparticles, magnetic particles, and ZIF-8. Some microspheres were synthesized from synthetic polymers such as vinylic polymer and polydopamine (PDA) through a facile fabrication process. Natural polymers (such as cellulose, alginate, and chitosan) that are biodegradable and eco-friendly are also used. The adsorbents used in industrial application require high adsorption capacity, thermal stability, and recyclability. Batch adsorption experiments were conducted to investigate the optimal conditions, influence of related factors, and adsorption capacities. Insights regarding the adsorption mechanisms were given from the kinetic model, isotherm model, and various characterization methods. The recyclability is investigated through regeneration ratio, or their maintenance of their capability through repeated adsorption-desorption cycles. The high potential of polymer microsphere for the removal of pollutants from wastewater is shown through the high adsorption capacities, environmentally friendliness, and high stability.

Interaction Influence of Contact Time and pH on Cobalt Retention by Carbon Nanotubes Bearing Various Loads of TiO2 and Fe3O4

&lt;P&gt;Background: Nanomaterials have facilitated remarkable advances in the remediation of many environmental problems. A few studies have tackled the removal of Co (II) from aqueous solutions using nanomaterials. Herein, we studied the retention kinetics of cobalt species on carbon nanotubes (CNTs) bearing different amounts of TiO2 and Fe3O4 nanomaterials individually. &lt;P&gt; Methods: CNTs and their TiO2/Fe3O4-modified nanomaterials were well characterized. Cobalt retention by these adsorbents was investigated considering different influencing factors such as Co (II) content, solution pH, and time. The kinetic data were fitted with pseudo-first-order, pseudosecond- order rate models, and intra-particle diffusion models for better elucidation of the mechanism of Co retention. &lt;P&gt; Results: XRD evidenced the formation of TiO2 and Fe3O4. High loads of both oxides were needed for higher and faster Co retention by CNTs. Co retention capacity increased with increasing the solution pH. The pseudo-second-order model presented the kinetics of Co retention at 30 oC, and 48% of available capacity was attained within the first hour of interaction by CNT-TiO2 and with a moderate S/L ratio of 0.5 g/L. Co retention was increased with the amount of oxide to reach a maximum value of 16. 40 mg/g (90.2% TiO2) and 13.60 mg/g (48.2% Fe3O4). The Jovanović equilibrium model predicted the maximum retention values as the nearest to the experimental ones. &lt;P&gt; Conclusion: The potential of CNT-Fe3O4/TiO2 nanomaterials has been successfully demonstrated for the removal of cobalt, which makes them highly attractive and cost-effective adsorbents for wastewater treatment. The reported retention and removal rate values were relatively better than those seen in the literature. Loading different active oxides by CNTs is an interesting research area as selective adsorbents can be fabricated with affordable experimental costs.

Advances in Nanocellulose Based Materials as Adsorbent for Wastewater Treatment

Environmental pollutions especially water pollution has been a persisting issue battle by mankind worldwide. There are various kinds of pollutants in contaminated water where it varies from heavy metals, organic dyes, pharmaceutical products and others. The presence of all these pollutants poses adverse effect to both animal and human as most of them are toxic. With the depleting sources of clean water, the needs of treatment for polluted water are highly demanded. Adsorption process for removal of contaminant has been gaining popularity due to the easy application. Nanocellulose based materials emerged as one of the most interesting adsorbents to be applied. This is due to its sustainability in production which is aligned with the current interest of research. The main source of nanocellulose is plants and nowadays, majority of researches utilize agricultural and industrials wastes as the sources. This article focuses on the nanocellulose and its classification, the sources of nanocellulose and its application as adsorbent for various types of pollutants.

Waste Biomass and Biomaterials Adsorbents for Wastewater Treatment

This paper highlights some of the commonly used bio-based materials studied for their applicability as adsorbents in wastewater treatment. Additionally, few processing techniques employed to enhance the ability and or affinity of the adsorbents for wastewater treatment have been discussed. More so, some of the commonly used characterization techniques such as Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FTIR) spectroscopy among others often employed in a bid to elucidate the properties and morphologies of the adsorbents as well as the potential mechanism(s) underlying the adsorbate-adsorbent interaction(s) has also been extensively conferred. The potential draw-backs, recommendations and future perspectives on the use of bio-based materials as adsorbents in wastewater treatment has also been discussed in the concluding section of this paper.

Melamine sponge loading improves the separation performance of magnetic hydroxyapatite for Pb(Ⅱ) adsorption

Magnetic materials as adsorbents for wastewater treatment have attracted considerable attention because of the ease of separation of adsorbents for reuse. However, the efficient separation of magnetic materials, particularly nanoscale materials, remains challenging. Therefore, in this study, we developed an innovative method to enhance the separation performance of magnetic hydroxyapatite (MP) using melamine sponge (MS) loading. It was found that, although the magnetic moments of MP decreased from 15.54 emu/g to 11.51 emu/g after MS loading, MS-loaded MP (MPMS) exhibited better magnetic separation performance than MP. The analysis of adsorption isotherms suggests that the theoretical maximum adsorption capacity of Pb2+ at an initial pH of 4.85 using MPMS was 139.28 mg/g. Combined with adsorption kinetics and thermodynamics analysis, adsorption was categorized as a chemical, heterogeneous, and endothermic process. Moreover, in the adsorption mechanism, cation exchange, electrostatic interaction, dissolution/precipitation, and surface complexation mechanisms contributed 70.96%, 4.39%, 6.10%, and 18.55%, respectively, to the total Pb2+ removal under the experimental conditions. Hence, we provide a quick and low-cost solution for enhancing the downstream separation of magnetic adsorbents for reuse.

Nutmeg seed shell biochar as an effective adsorbent for removal of remazol brilliant blue reactive dye: kinetic, isotherm, and thermodynamic study

ABSTRACT Biochar derived from agricultural wastes has emerged as an effective adsorbent for wastewater treatment. However, studies on nutmeg seed shell (NSS) utilization in textile wastewater treatment is limited. This study explores the possibility and efficacy of using a modified nutmeg seed shell as an adsorbent to remove remazol brilliant blue reactive dye (RBBR) from the aqueous wastewater. The adsorbent was characterized before and after adsorption using FTIR, FE-SEM, TGA, and XRD, respectively. Response surface methodology (RSM), based on Box–Behnken design (BBD), was utilized to optimize the effects of initial concentration (5–100 mg/L), pH (2–12), contact time (10–120 min), and adsorbent dosage (0.5–3 g/L) on the RBBR removal. The quadratic model generated by RSM describes the best relationship between the independent parameters and the dye removal efficiency. The optimum conditions for the RBBR dye removal were observed at an initial concentration of 100 mg/L, adsorbent dose of 2.85 g, pH of 10, and contact time of 110 min, which resulted in 93.41% removal efficiency. The adsorption model fits the pseudo-second-order and Langmuir isotherm models with correlation factors (R2 ) > 0.99. Langmuir adsorption isotherm gives an optimum adsorption capacity of 173.31 mg/g. The adsorption isotherm and kinetics study shows that the adsorption process is based on monolayer chemisorption. The thermodynamic studies suggest that adsorption is a spontaneous and endothermic process. The result indicates that modified NSS is an efficient adsorbent for removing reactive dye RBBR.

Ultrasonic-assisted synthesis of zeolite/activated carbon@MnO2 composite as a novel adsorbent for treatment of wastewater containing methylene blue and brilliant blue.

In this study, zeolite/activated carbon@MnO2 composite was used as a novel adsorbent to eliminate methylene blue (MB) and brilliant blue (BB) dyes from aqueous media. To this end, activated carbon (AC) was produced by Ziziphus Spina-Christi leaves and then used to synthesize zeolite/AC@MnO2 composite. Various analyses such as BET, SEM, EDX, Map, FTIR, and XRD were performed to determine the surface features of the above composite. BET analysis indicated that the aforementioned composite has a mesoporous structure. Also, the best conditions for the adsorption of MB and BB dyes were obtained at pH of 9 and 2, temperature of 25°C, adsorbent dosage of 1 and 2g/L, initial dye concentration of 10mg/L, and contact time of 40 and 60min, respectively. Under optimal conditions, the utmost removal efficiency of MB and BB dyes using the zeolite/AC@MnO2 composite was 98.43% and 96.54%, respectively, indicating significant adsorption efficiencies. Moreover, the utmost adsorption capacity of MB and BB dyes was 67.56 and 66.22mg/g, respectively. Furthermore, intraparticle and film diffusion mechanisms were very important in the adsorption process. Besides, thermodynamic and equilibrium studies indicated that the adsorption process is exothermic, physical, and spontaneous. Generally, the aforementioned composite has a significant adsorption capacity and can be a suitable adsorbent to eliminate cationic dyes from industrial effluents.

Removal of COD in wastewater by magnetic coagulant prepared from modified fly ash.

In this paper, magnetic coagulants (Fe-AFA, Fe-BFA) were prepared, by mixing acid-modified fly ash (AFA) and base-modified fly ash (BFA) with magnetic components, as adsorbents for chemical oxygen demand (COD) in desulfurization wastewater and their adsorption kinetics and mechanism are reported. BET, SEM, EDS, FTIR, XPS, magnetization intensity, and batch experiments on coagulation kinetic and adsorption isothermal characteristics of magnetic coagulants were carried out. The results show that Fe-AFA has the best COD adsorption performance and superparamagnetism, and the COD removal amounts can reach 5.69mg/g, which is 112.43% higher than the raw fly ash. It was also found that the quasi-second-order kinetic and Langmuir equation could well describe the COD coagulation process. Thermodynamic tests results showed that the COD removal was a spontaneous, endothermic, and irreversible process. Reusability of magnetic coagulants was investigated. After five cycles, the COD removal amount of Fe-AFA was 2.74mg/g. These findings provide a feasible method for environmental-benign utilization of fly ash as low-cost adsorbents in wastewater treatment.

MXene-based nanomaterials as adsorbents for wastewater treatment: a review on recent trends

MXene-based nanomaterials as adsorbents for wastewater treatment: a review on recent trends

A Review on Bamboo as an Adsorbent for Removal of Pollutants for Wastewater Treatment

Water and wastewater treatment are very important for obtaining clean and sanitary water as well as protecting the environment from toxic pollutants. Not only enriched with cellulose and carbon but the abundant resources of bamboo also make it suitable to be utilized as an adsorbent. With the right processing technologies and improvements, the potential of bamboo is unlimited. This study review provides knowledge on the use of bamboo-based adsorbents for the removal of contaminants and pollutants in wastewater in the form of activated carbon, biochar, and aerogel. This review highlighted bamboo utilization and its relevance as an adsorbent for wastewater treatment. The technologies for the processing and improvement of bamboo as well as the performance of the bamboo-based adsorbents are also discussed in this study. The adsorption capacity of bamboo has shown improvement with modification and good adsorption capacity achieved with some of the adsorbent being able to be recycled and reused.