Preparation Of Adsorbents Research Articles

Understanding the vacuum autoreduction behavior of Cu species in CuCl/NaY adsorbent for CO/N2 separation

CuCl/NaY is the most representative π-complexation adsorbent, prepared by solid thermal dispersion followed by vacuum thermal activation. However, determining the autoreduction behavior of Cu species for CuCl/NaY adsorbent in vacuum thermal activation has rarely been researched. This study characterized the valence state, location, and types of Cu species during thermal dispersion and vacuum activation. During the thermal dispersion, Cu species were uniformly dispersed into NaY micropores. Under vacuum activation at 100 °C, the location of Cu species changed, migrating from supercages to near the plane (toward the sod cage or the supercage side) of the 6-membered ring connecting the supercage and sod cage. However, by activating at 150 °C, vacuum autoreduction occurred: (Cu2+–O−)Cl− species evolved into Cu+Cl− species. This was accompanied by the migration of Cu(I) species to the appropriate CO adsorption site on the plane center of the six-membered ring connecting the supercage and sod cage in the NaY framework, which achieved confined dispersion. The CO adsorption capacity of CuCl/NaY activated at 150 °C was 2.75 mmol/g, significantly higher than when activated at 100 °C. When activated at 200 °C, Cu(II) species was further reduced to Cu(I) slightly, which had not migrated to an effective adsorption site. Our results show the Cu species’ evolution and autoreduction behavior for CuCl/NaY adsorbent under vacuum thermal activation, and they can serve as a reference to guide the preparation of π-complex adsorbents.

Economical-effective purification of brackish water through an integrated capacitive desalination & boron adsorption system

The escalating scarcity of high-quality water for potable, industrial, and agricultural use necessitates innovative methods to augment freshwater supply from unconventional sources. This study primarily aims to lower boron (B) and chloride (Cl−) levels in brackish water to meet water quality standards of B < 0.5 mg/L and Cl− < 250 mg/L. To meet this goal, an innovative adsorbent, OQAS-AC@NGO, was used for boron removal. It combines organosilicon quaternary ammonium chloride (OQAS) modified activated carbon (AC) within a self-assembled nitrogen-doped graphene oxide (NGO) structure. Before boron removal, a capacitive deionization (CDI) system was used, employing OQAS-AC as the anode and COOH-modified AC as the cathode for chloride ion electrosorption. Through this cooperation procedure, the treated water meets the required quality standards while significantly reducing chemical costs by approximately 13.5 times when compared to conventional ion exchange resin methods for adsorbent regeneration. Moreover, the OQAS-AC@NGO adsorbent sustains its efficiency through multiple cycles, outperforming non-assembled N-GO in terms of yield, performance, and water flux. This underscores the cost-effective adsorbent preparation and enhanced water productivity. Economic analysis endorses the integrated CDI & B adsorption approach, advancing both sustainable water treatment processes and practical industrial applications.

Homogeneous synthesis of Schiff base modified PAMAM dendrimers/silica for efficient adsorption of Hg(II)

Water pollution caused by Hg(II) is a serious environmental issue and poses great risk to human health. Adsorption is a promising method for decontaminating aqueous Hg(II). Therefore, a family of Schiff base modified polyamidoamine (PAMAM) dendrimer/silica (G0-T1/x-S, G1-T1/x-S and G2-T1/x-S (x = 2, 4, 6)) were synthesized by homogeneous method for removing Hg(II) from water solution. The adsorption property of the adsorbents for Hg(II) was comprehensively evaluated. The adsorption capacity for Hg(II) was found to depend on the dendrimer generation. The effects of solution pH, time, temperature, and interfering metal ions on the adsorption property for Hg(II) were determined by selecting G0-T1/2-S, G1-T1/2-S and G2-T1/2-S as models. The optimal pH for the adsorption of Hg(II) is 6. Adsorption kinetic shows that the adsorption is fast at initial, and the equilibrium can be reached at 400 min. Adsorption isotherm demonstrates the increase of temperature and concentration can promote the adsorption for Hg(II). The kinetic and isotherm process can be fitted by pseudo-second-order kinetic model and Langmuir model, respectively. The adsorbents display good adsorption selectivity for Hg(II) and the functional groups of CONH, C-N, C = N and OH dominate the adsorption. The adsorbents exhibit good removal efficiency for Hg(II) from simulated industrial wastewater with the coexistence of multiple pollutants. Moreover, the adsorbents show excellent reusability as the regeneration rate of G2-T1/2-S can still maintain 92.45 % after the tenth adsorption–desorption cycles. The research work provides a feasible method for the preparation of efficient adsorbents to remove aqueous Hg(II) with practical values.

Efficient treatment of palladium from wastewater by acrolein cross-linked chitosan hydrogels: Adsorption, kinetics, and mechanisms

Herein we present a study on the preparation and properties of a hydrogel adsorbent for treatment of wasted palladium souring from actial petrochemical industrial wastewater. Chitosan was used as the raw material and acrolein as the cross-linking agent for the hydrogel (A/CS). The adsorption behaviors of the hydrogel for Pd(II) ions were characterized and analyzed. The effect of pH, temperature, adsorption kinetics, and thermodynamics were investigated. Langmuir models were employed to describe the adsorption isotherms, while the pseudo-second-order equation was applied to describe the adsorption kinetics. The experimental results demonstrated that the adsorption was a monolayer chemical adsorption, and the adsorption capacity was found to reach 505.05 mg/g under optimal conditions. In addition, FT-IR and XPS analyses, combined with MS calculations confirmed that chelation and electrostatic attraction were dominated in the adsorption process. Overall, the development of this hydrogel adsorbent will provide a practical approach to the treatment of industrial wastewater containing palladium and have great potential for practical applications.

Enhanced selective adsorption of low-concentration phosphorus via layered La2O2CO3 with high environmental adaptability

The highly selective deep purification of low-concentration phosphorus has garnered increasing attention. This article employs a novel strategy involving the calcination and reconstruction of Mg/La LDH, leading to the successful preparation of La-based adsorbents (LC-1, LC-2, LC-3). Among them, LC-1, which features a layered La2O2CO3 structure, exhibits excellent phosphorus adsorption performance. At a low dosage (0.1 g/L), it rapidly reached adsorption equilibrium within 100 min, ultimately reducing the phosphorus concentration from 10 mg/L to less than 0.02 mg/L. In the pH 2–13 tests and regeneration tests, LC-1 displays minimal La leaching (<0.04 mg/L) and stability of 10 cycles phosphorus removal (adsorption capacity exceeds 90 mg/g), in contrast to the performance of Mg/La LDH (limited to 5 cycles). LC-1 also has extraordinary environmental adaptability, exhibiting a phosphorus adsorption capacity of over 95.7 mg/g in the presence of interfering anions and humic acid (HA), as well as maintaining a phosphorus adsorption capacity of over 85 mg/g at 5 °C. Analysis suggests that the novel preparation strategy was conducive to forming stable La2O2CO3 species, alleviating metal ion dissolution and optimizing the content and proportion of La3+, electrophilic oxygen species (O22−/O−) and interlayer CO32−. The above are critical factors in controlling the adsorption rate, improving the pH resistance and stability of adsorbents. In summary, La2O2CO3 has not only exhibited outstanding adsorption performance but also boasted a simple preparation strategy, rendering it highly promising for applications in the removal of low-concentration phosphorus.

Preparation of sulfur self-doped coal-based adsorbent and its adsorption performance for Cu2.

The limited application of high-sulfur coal (HSC) and the increasing severity of copper pollution in solution are two pressing issues. To alleviate such issues, a sulfur self-doped coal-based adsorbent (HSC@ZnCl2) was obtained by pyrolysis (850°C, 60min holding time) of HSC and ZnCl2 with a mass ratio of 1:0.5. The results adsorption experiment revealed that the endothermic and spontaneous adsorption process was consistent with the Sips isothermal model (R2 = 0.992) and pseudo-second-order kinetic (R2 = 0.994), and that the adsorption process with a maximum adsorption capacity of 11.97mg/g. Meanwhile, the adsorption of Cu2+ onto HSC@ZnCl2 was a result of the synergistic effects of various interactions, such as the complexation by oxygen-containing functional groups, electrostatic attraction and surface precipitation by ZnS on the adsorbent surface, and the process also included redox reaction. The findings of this work indicate that the preparation of sulfur self-doped coal-based adsorbent prepared from high-sulfur coal is a promising method for its large-scale utilization.

3D Wood Microfilter for Fast and Efficient Removal of Heavy Metal Ions from Water.

Adsorption is an effective method for the treatment of heavy metal ions in water; however, the existing adsorbents are complicated to prepare, and costly and difficult to recover. In this work, a 3D wood microfilter was prepared by modifying wood for the removal of heavy metal contaminants from water. First, a green deep eutectic solvent was used to remove lignin from beech wood. Then citric acid and l-cysteine were sequentially used to graft carboxyl and sulfhydryl groups (-SHs) on the surface of cellulose. Finally, a three-dimensional wood microfilter with an abundant porous structure and adsorption sites was formed. The adsorption kinetics and adsorption isotherms of heavy metal ions on the 3D wood microfilter were systematically investigated using Cu2+ and Cd2+ as model species. The results showed that the 3D wood microfilter had a fast adsorption rate and high saturation capacity for both Cu2+ and Cd2+. Based on the advantages of easy processing and multilayer assembly and stacking, a three-layer wood microfilter was designed to achieve high flux rate (1.53 × 103 L m-2 h-1) and high efficiency (>98%) for the removal of heavy metal ions in water. The enhancement mechanism of the adsorption process of Cu2+ and Cd2+ by the 3D wood microfilter was investigated using SEM and EDS, FTIR, and XPS characterization. The simple synthesis method and high adsorption efficiency of this wood microfilter provide a new strategy for the preparation of cheap, efficient, and recyclable adsorbents for heavy metal ions in water.

Application of common industrial solid waste in water treatment: a review.

Industrial solid waste has a wide range of impacts, and it is directly or indirectly related to land, atmosphere, water, and other resources. Industrial solid waste has a large amount of production, complex and diverse components and contains a variety of harmful substances. However, as industrial by-products, it also has a lot of available value. Industrial solid waste has been continuously studied in water treatment due to its special composition and porous and loose structure. It is known that there are few reviews of various industrial solid wastes in the field of wastewater treatment, and most of them only discuss single industrial solid waste. This paper aims to sort out the different studies on various solid wastes such as fly ash, red mud, wastewater sludge, blast furnace slag and steel slag in dyeing, heavy metal, and phosphorus-containing wastewater. Based on the modification of industrial solid waste and the preparation of composite materials, adsorbents, coagulants, catalysts, filtration membranes, geological polymers, and other materials with high adsorption properties for pollutants in wastewater were formed; the prospect and development of these materials in the field of wastewater were discussed, which provides some ideas for the mutual balance of environment and society. Meanwhile, some limitations of solid waste applications for wastewater treatment have been put forward, such as a lack of further researches about environment-friendly modification methods, application costs, the heavy metal leaching, and toxicity assessment of industrial solid waste.

The adsorbent preparation of lanthanum functionalized sponge based on CMC coating for effective phosphorous removal.

Eutrophication is a severe worldwide concern caused by excessive phosphorus release. Thus, significant efforts have been made to develop phosphorus removal techniques, particularly by nanomaterial adsorption. However, because of the limitations associated with nanoparticles including easy agglomeration, and separation challenges, a novel nanocomposite adsorbent with great adsorption performance is urgently required. A sponge adsorbent (MS-CMC@La) was developed in this study to remove phosphorus using melamine sponge (MS), LaCl3, and sodium carboxymethyl cellulose (CMC). The results of SEM/EDS, FTIR, and XPS demonstrated that La was well-dispersed on MS-CMC@La. Adsorption isotherm and kinetics met with the Langmuir model (R2 = 0.981) and the pseudo-second-order kinetics (R2 = 0.989), respectively. The maximum adsorption capacity of MS-CMC@La was found to be 15.28mg/g; the material exhibited excellent selectivity toward phosphorus in the presence of coexisting anion except of F-; the adsorptionbehavior was greatly impacted by pH. Furthermore, the electrostatic attraction, ligand exchange and inner-sphere coordination regulate the phosphate adsorption mechanism, with inner-sphere coordination dominating. In summary, the nano-enriched materials developed in this study are capable of facilitating the application of functionalized sponges in the field of wastewater.

Preparation and characterization of biopolymer-based adsorbents and their application for methylene blue removal from wastewater

In the present study, four biopolymer-based materials consisting of native corn starch (CS), phosphate corn starch (PS), starch nanocrystals (SNCs), and phosphate corn starch nanocrystals (PSNCs) were synthesized and used for methylene blue (MB) removal as a function of various parameters, including initial MB concentration (C0, 10–500 mg L−1), adsorbent dosage (Cs, 0.02–0.15 g), contact time (t, 5–15 min), solution pH (2–11), and temperature (25–45 °C). The removal percentage of MB increased dramatically upon increasing the biopolymer dosage, temperature, and pH; while it decreased upon increasing the initial MB concentration. The adsorption behavior of biopolymer-based materials towards MB was found to be accurately described by the pseudo-second-order kinetic and Langmuir isotherm models. According to the Langmuir model, the maximum adsorption capacities of the adsorbents were ordered as follows: PSNCs (88.53 mg g−1) > SNCs (79.55 mg g−1) > PS (73.17 mg g−1) > CS (63.02 mg g−1). PSNCs was able to remove 96.8% and 76.5% of 20 mg L−1 MB in greywater and petrochemical wastewater, respectively, at an optimum pH of 9 and retained 86.42% of its usability even after five adsorption–desorption cycles. The analysis of the surface charge of the adsorbents before and after MB adsorption, combined with the FTIR spectrum of MB-saturated biopolymer-based materials, provided evidence that electrostatic interactions was the primary mechanism involved in the adsorption of MB. Meanwhile, hydrogen bonding and π–π interactions were found to have a minor contribution to the adsorption process. Based on the results, it can be inferred that PSNCs has promising potential as an adsorbent for the treatment of MB-containing wastewater, owing to its exceptional properties, which include high adsorption capacity, low cost, and applicability for multiple reuses.

Life cycle assessment of carbon-based adsorbent preparation from algal biomass

The adsorbent prepared by algae was found to be very feasible and effective for removing tetracycline from water. Therefore, this manuscript investigated the capacity of adsorbents through co-pyrolysis of Enteromorpha (EN) and Chlorella vulgaris (CV). Through the experiment, it was determined that the pyrolysis of Enteromorpha and Chlorella vulgaris was carried out at 500 °C at the mixing ratio of 2∶8. The obtained biochar was mixed with NaOH at 1∶0.5 and activated at 800 °C. The mixed algae-based adsorbent had the highest removal rate of tetracycline (97.56%). To further evaluates the environmental impact of the adsorbent preparation process, OpenLCA was applied to the three adsorbent preparation processes using Enteromorpha (EN), Chlorella vulgaris (CV) and mixed algae (MIX). The results show that EN-based adsorbent preparation has the least environmental impact. This is because CV requires much freshwater during cultivation, while EN is cultured in ocean. The culture of CV-based and MIX-based adsorbents account for the majority of all environmental impact indicators. For example, the CO2 emissions of CV and MIX culture account for 75.05% and 69.21% in preparation process, respectively. The sensitivity analysis showed that the environmental impact indicators of CV-based and MIX-based adsorbents preparation was extremely sensitive to aquaculture water. If 80% of the aquaculture water is replaced with aquaculture wastewater, the environmental impact of the MIX-based adsorbent preparation will be the least of the three schemes. The LCA of algae-based adsorbent preparation was carried out in this study, which provided guidance for the optimization of adsorbent preparation engineering.

The crucial role of different NaOH activation pathways on the algae-derived biochar toward carbamazepine adsorption

In this study, algae present in wastewater were utilized as precursors for synthesizing a range of biochar (BC) samples to serve as efficient adsorbents for the removal of carbamazepine (CBZ). The impact of modification on BC, activated through the NaOH impregnation method (IBC), and the NaOH dry mixing-pyrolysis (DBC) method, was systematically explored. It was observed that only the surface of IBC became rough due to NaOH impregnation activation, while the DBC structure exhibited additional fine pores within its interior. Furthermore, after NaOH activation, a significant number of oxygen-containing functional groups were introduced onto the surface of the prepared BC samples, with the proportion of O species differing between the two NaOH activation methods. Based on the results from adsorption experiments and kinetic model simulation, CBZ adsorption by BC samples followed a monolayer homogeneous adsorption reaction with excellent pH tolerance, where H-bond (CO⋯H–N) was identified as the primary driving force. From an adsorption thermodynamics perspective, it is hypothesized that the high proportion of CO causes the ΔG value to shift from positive to negative, indicating that CBZ adsorption by DBC is a spontaneous reaction. Under optimal conditions, the DBC samples demonstrated an exceptional adsorption capacity, reaching 118.4 mg/g, with the removal rate of CBZ exceeding 99 %. This study offers theoretical insights into the preparation, modification, and adsorption mechanisms of BC-based adsorbents.

Study on iodine adsorbents preparation and performance for different TEDA ionic liquids

Study on iodine adsorbents preparation and performance for different TEDA ionic liquids

Preparation of a Lignin-Based Adsorbent from Xylitol Residue for the Capture of Metal Ion in Aqueous Solutions

Preparation of a Lignin-Based Adsorbent from Xylitol Residue for the Capture of Metal Ion in Aqueous Solutions

Insight into the impacts of pyrolysis time on adsorption behavior of Pb2+ and Cd2+ by Mg modified biochar: Performance and modification mechanism

Co-pyrolysis biomass and alkaline metals can effectively improve the adsorption performance of heavy metals (HM). Nevertheless, the researchers have ignored the relationship between the change of alkaline metal morphology and adsorption during pyrolysis. In this article, according to control the pyrolysis time (30, 60, and 180 min) synthesized Magnesium (Mg) modified biochar (MBCX) by using MgCl2·6H2O and soybean straw under 400 °C. The sorption capacities of MBC60 and MBC180 for Pb2+/Cd2+ increased by 38.65%/213.29%, 44.57%/230.36%, and the selectivity coefficient of Pb2+/Cd2+ increased by 113.28%/209.49%, 213.58%/253.62%, respectively, compared with MBC30. Additionally, the characterization results demonstrated that MgO dominated the surface phases of MBC60 and MBC180, whereas MgCl2 dominated the surface phases of MBC30. Moreover, according to the results of DFT calculation, the adsorption energy (Eads) of MgO for Pb2+ (−0.537 eV) and Cd2+ (−0.347 eV) was lower than that of MgCl2 (Pb2+: 0.37 eV, Cd2+: −0.185 eV), so that, MBC60 and MBC180 had higher sorption capacities for Pb2+ and Cd2+ than MBC30. Therefore, this work provides a new sight to clear the mechanism for modified biochar by alkali metal oxide and practical and theoretical guidance for adsorbent preparation with high adsorption ability for HMs.

Preparation, characterization, and application of stable naphthalenediimide‐based metal–organic framework for cooperative capture low concentration uranium from wastewater

AbstractExtracting uranium from real water samples remains a great challenge due to low uranium concentration, concentrated competing ions and volumes of water. The design and preparation of uranium adsorbents with high efficiency and affinity are still difficult. Herein, we presented a facile one‐pot strategy to obtain a novel metal organic framework (denoted as Mn‐NDISA) for stable and efficient trapping of low concentration uranium. Mn‐NDISA with a built‐in hydrophobic cavity can boost the absorption affinity to 1.99 × 106 mL g−1 through the cooperative capture composed of electrostatic interaction, coordination force and hydrogen binding. Owing to the coordination‐available oxygen sites in flexible framework, a rapid kinetic equilibrium was achieved in just 25 min. Moreover, these exceptional adsorption features enabled Mn‐NDISA to successfully capture the naturally occurring uranium traces (~ppb) in wastewater samples, making it one of the most influential absorbents toward UO22+ ever reported. The experimental and theoretical studies revealed that the electrostatic attraction came from the surface negatively charged Mn‐NDISA and the positively charged UO22+. The coordination originated from Lewis basic hydroxyl, carbonyl groups, and Lewis acid UO22+, while hydrogen bonds further reinforced the as‐formed uranium binding complex. This research offered a promising cooperative capture strategy to improve the uranium affinity of the pristine MOF for trace contaminants removal in environmental remediation fields.

High adsorption of methyl orange by nitrogen-doped activated carbon derived from kraft lignin via self-activation

As adsorbents, nitrogen-doped activated carbons are attracting increasing interest in the field of environmental protection, pharmaceutical and food industries due to their tunable pore structures, abundant surface functional groups and variable charges. However, the main factor limiting the commercialization and mass production of the activated carbons is the cost of adsorbent preparation. A nitrogen-doped activated carbon derived from kraft lignin in black liquor was produced by self-activation via endogenous alkali, and was used as an adsorbent of anionic methyl orange for its very low cost. It was indicated that the activated carbon with a rich pore structure, having a specific surface area of 1124.78 m2 g−1 and a total pore volume of 0.60 cm3 g−1, was obtained under a mass ratio of 1:2 of organic matter in the black liquor to diethylenetriamine and an activation temperature of 850 °C. Furthermore, the adsorption capacity of the activated carbon for methyl orange in simulated wastewater was evaluated, and it exhibited excellent performance with a maximum adsorption capacity of 373.95 mg g−1 under the optimized conditions as the methyl orange solution is at an initial concentration of 175 mg L−1, pH 7.8 and an adsorbent dosage of 0.4 g L−1. Adsorption kinetics, adsorption isotherms and adsorption thermodynamics were also studied. And the adsorption process of the activated carbon was found to be in accordance with the Pseudo-second-order kinetic model and the Langmuir model. This work provides a novel strategy for producing lignin-derived activated carbon from dried black liquor by self-activation with a low cost and timesaving approach.

Optimization of Fe2O3@BC-KC composite preparation for adsorption of Alizarin red S dye: Characterization, kinetics, equilibrium, and thermodynamic studies

Optimization of the preparation conditions of Fe2O3@BC-KC composite was investigated. The adsorbent preparation involved chemical impregnation with FeCl3 and subsequent thermal activation. Calcination temperature, calcination time, mixing ratio, and heating rate were the independent variables. The adsorption efficacy of Fe2O3@BC-KC was assessed with Alizarin red S (ARS) dye uptake and the best result was obtained at calcination temperature of 611 °C, calcination time of 102 min, mixing ratio of 3.0:1 w/w of BC/KC, and heating rate of 10.85 °C/min. The adsorbent was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM). Furthermore, the highest grade Fe2O3@BC-KC was used to carryout batch adsorption studies for ARS at different levels of time, solution pH, adsorbent dosage, and adsorption temperature. An optimum adsorption capacity of 174.9 mg/g was recorded at 0.25 g/L Fe2O3@BC-KC dosage, pH of 2, and Temp. of 45 °C, and 90 min adsorption time. Similarly, optimum removal rate of 98.7% was obtained at 1.75 g/L Fe2O3@BC-KC dosage, pH of 2, and adsorption time of 90 min. The kinetic data was well fitted into the pseudo second order model, while the equilibrium data was most suitably described by Redlich-Peterson three parameter isotherm model. Consequently, the process was adjudged to be monolayer with uniformly distributed affinity for ARS molecules. Mechanistic studies revealed that although intraparticle diffusion took part in ARS adsorption, external mass transfer majorly controlled the process. Thermodynamic parameters (ΔG0, ΔH0 and ΔS0) revealed that the adsorption of ARS on the Fe2O3@BC-KC composite was a favorable, spontaneous, and endothermic chemisorption process.

Preparation of light-colored bio-based particles by isocyanate-modified lignins and its application for tetracycline adsorption

A practical method for the preparation of lignin derivatives-light-colored bio-based particles (LC-BP) via the modification of hexamethylene diisocyanate (HDI) is presented in this work. In the mixed EtOH/H2O system, the change of solvent polarity induced the self-assembly of the lignosulfonate (LS) with the hydrophobic chromophores encapsulated inside the particles. The color of LS was reduced by the polymerization between the isocyanate groups (-N=C=O) of HDI and hydroxy groups of LS. Compared with the typical lignin-based adsorbent preparation process in the past, this is a simple, direct, and efficient preparation method and the synthetic LC-BP has good chemical stability and resistance to heat, acid and alkali. This effectively solves the problem that LS has high water solubility and is difficult to use directly for wastewater treatment. To investigate the properties, the synthetic LC-BP was characterized by SEM, specific surface area, L*a*b* (CIELAB) color space, FT-IR, XPS, and TGA. The results showed that the LC-BP exhibited obvious advantages in color reduction with a low CIE-L* value. The LC-BP exhibits a scale-like intercalation structure, which makes it a promising candidate for adsorbing tetracycline (TC) from wastewater. The conditions of pH, adsorbent dosages, adsorption time, and initial TC concentration were investigated, and the adsorption performance of LC-BP for TC was significantly better than that of conventional polyurethane particles (PP). The adsorption fitted the Langmuir model and there were hydrogen bonding, π-π conjugated binding, and electrostatic attraction during the absorption process. The adsorption capacity was up to 53.1 mg/g, and the removal rate was 67 %. The utilization of LC-BP, a low-cost, effective, and renewable resource derived from natural biomass, holds immense practical and economic potential in wastewater treatment.

Efficiency of chemically activated raw and calcined waste fish bone for adsorption of Cd (II) and Pb (II) from polluted water

AbstractBone biochar is used as an adsorbent in water pollution control because of its high surface area and pore volumes. This study is attempting to prepare a low-cost adsorbent from waste fish bones by chemical activation and use it for the removal of Cd2+ and Pb2+ from polluted water. The preparation of fish bone adsorbents involved two methods. The first method includes the chemical activation of waste fish bone using different chemical activators (0.001 M HNO3, 0.1 M NaOH, 0.5% H2O2, and ethanol) (FB), while the second one includes the calcination of waste fish bone after the chemical activation at 873 K (FB-Hy). The synthesized fish bone adsorbent (FB) was characterized by electron microscopy (SEM), X-ray diffractometer (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area, and Fourier transform infrared (FT-IR). The effectiveness of the prepared adsorbent (FB) in removing Pb and Cd was evaluated based on contact time, solution pH, solution temperature, initial metal concentration, and adsorbent dose. Metal concentrations were measured by atomic absorption spectroscopy. The results show that 0.1 M NaOH activation of bone waste (FB) is suitable for higher adsorption of Cd2+ and Pb2+ compared with other activators. The maximum adsorption of Pb and Cd with the FB adsorbent was 99.74 and 99.35%, respectively, at optimum conditions (pH 6.0, contact time 30 min, initial metal concentration 10 ppm, adsorbent dosage 0.1 g, and temperature at 328 K). The results of kinetic adsorption obeyed a pseudo-second-order model. Freundlich and Langmuir isotherms were applied, and the adsorption was found to fit well with the Langmuir model. This study ended with the success of preparing an eco-friendly and low-cost fish bone adsorbent from the waste fish bone and using it for the removal of Cd2+ and Pb2+ from polluted water.