Copper Adsorption Research Articles

Assessing the Efficiency and Mechanism of Copper Adsorption onto Biochars derived from Corn Straw and Cow Manure

Assessing the Efficiency and Mechanism of Copper Adsorption onto Biochars derived from Corn Straw and Cow Manure

Low-cost date palm fiber activated carbon for effective and fast heavy metal adsorption from water: Characterization, equilibrium, and kinetics studies

The removal of heavy metals in an aquatic environment is a crucial problem because the pollution by heavy metals is common in water systems. In this study, a low-cost activated carbon from the waste of date palm fiber (AC-DPF) was prepared for the potential adsorption of lead and copper from simple and binary systems. The surface area of AC-DPF was 1603.496 m2/g. The effect of factors influencing the adsorption of Pb(II) and Cu(II) by AC-DPF were discussed. The maximum adsorption efficiencies were 92 % and 80 % for Pb(II) and Cu(II), respectively. Furthermore, the AC-DPF adsorption was investigated kinetically and thermodynamically. A good fit of equilibrium results to the Langmuir model was achieved with a maximum adsorption capacity of 29.859 mg/g for Pb (II) and 25.048 mg/g for Cu(II). Competitive and antagonistic effects were observed in the multi-component system. Based on the results, AC-DPF was a highly promising, effective and feasible adsorbent for heavy metal removal potential.

Isotherms and Kinetic Studies of Copper Removal from Textile Wastewater and Aqueous Solution Using Powdered Banana Peel Waste as an Adsorbent in Batch Adsorption Systems.

Heavy metals that are present in surface water and wastewater are becoming a severe environmental problem. Because of its toxicity, heavy metal removal has become the main priority for environmental concerns. Banana peels are low-cost agricultural waste that could be used for heavy metal adsorption in wastewater. The main objective of this study is to evaluate the effective powdered banana peel for the removal of copper (II) from aqueous solutions and real wastewater. The banana peels were collected from domestic waste and ground to get a particle size of 150 µm. Powdered banana peel waste adsorbent (PBPWA) contained moisture content, ash content, volatile matter, and bulk density of 3.8%, 3.5%, 37.5%, and 0.02 g/cm3, respectively. The Fourier-transform infrared spectroscopy (FTIR) results showed that the alkyne, aldehyde, and amide functional groups were dominant in the powdered banana peel surface, and the scanning electron microscope showed the morphology of the adsorbent. Physicochemical characteristics of the raw wastewater revealed that the concentration of Cu (II), Pb (II), COD, BOD5, and Cd (II) were 2.75 mg/L, 2.02 mg/L, 612.16 mg/L, 185.35 mg/L, and 0.01 mg/L, respectively. At pH 5, adsorbent dose of 2g/100 mL, initial copper (II) concentration of 80 mg/L, and contact time of 90 min, the maximum removal efficiency of synthetic wastewater was 96.8% and textile wastewater was 69.0%. The adsorption isotherm fitted well with the Langmuir isotherm model at R2 = 0.99. The kinetics of copper (II) adsorption followed the second-order kinetic model better. Finally, these studies showed that banana peel bio-adsorbent is a potential adsorbent for heavy metal removal from synthetic and textile wastewater.

Selection of Operation Conditions for a Batch Brown Seaweed Biosorption System for Removal of Copper from Aqueous Solutions

Heavy metal exposure from wastewater is an important environmental issue worldwide. In the search for more efficient treatment technologies, biosorption has been presented as an alternative for contaminant removal from wastewaters. The aim of this work is to determine the operation parameters of copper adsorption followed by biosorbent regeneration. The algae Durvillaea antarctica and Lessonia trabeculata were used as biosorbents in batch experiments. These biosorbents were exposed to different conditions, such as pH, copper concentration, exposure time, mass-to-volume ratios and regeneration reagents. Batch sorption tests revealed an adequate pH of 4.5–5.0. The selected biosorbent was D. antarctica due to a considerably higher copper retention capacity. As a regenerating reagent, sulfuric acid was more efficient. For diluted copper solutions (10 to 100 mg L−1), a biosorbent particle size of between 1.70 and 3.36 mm showed better retention capacity than larger particles and a biosorbent mass-to-volume ratio of 10 g L−1 was desirable for these metal concentrations.

Novel copper desorption from a functionalized fly ash adsorbent using 1,1,1-trifluoro-2,4-pentanodione in ionic liquid [bmim][Tf2N]: Experimental and quantum chemistry calculations

In the context of the current environmental issues and the need to consolidate effective efforts according to the criteria of a circular economy, adsorption of copper from water with functionalized materials has shown high performance at low cost. However, desorption requires high amounts of acid and base to regenerate the functionalized material. In order to overcome this drawback, this work proposes an alternative desorbing phase based on a specific extractant for copper 1,1,1-trifluoro-2,4-pentanodione (TFA) dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. In this way, adsorption experiments were carried out using adsorbent fly ash, modified with a mesoporous siliceous material, and functionalized with 3-aminopropyl-triethoxysilane (APS). Under the operating conditions of this study, the best desorption performance was achieved using the lowest functionalization percentage of the absorbent material. The desorption percentage reached 45% after 200 min of contact with a stirred solution of TFA 0.2 [M] in IL. This percentage can be increased to around 70% through a second contact with fresh desorbing phase. Meanwhile, the conventional desorption technique with nitric acid showed faster kinetics and a slightly higher desorption percentage close to 50%. In turn, the final pH of the adsorbent slightly decreased when the proposed desorbing phase was used, representing an advantage over the use of acid. Additionally, it was possible to decrease the amount of desorbing phase allowing the concentration of copper. The COSMO-RS calculations indicate that a more hydrophobic IL could increase desorption percentage.

Fabrication of waste-derived porous geopolymer by community-scale carbonization and steam activation with potential copper adsorption

An integrated system for solid waste management in rural regions is presented in this study. Waste charcoal and activated carbon (AC) products were used for the production of absorbable geopolymers by subjecting municipal solid waste (MSW) and beachside waste (BSW) to a carbonization process (400 °C for 3 h) and steam activation (700, 800, and 900 °C for 1 h). The material characterization, mechanical property analysis, and copper adsorption performance were investigated. The results showed that the waste charcoal yields from MSW and BSW were 31.4% and 39.5%, respectively. The AC product yields of MSW and BSW were approximately 13.9–19.8% and 18.1–26.2%, respectively. Additional ingredients for geopolymer production are coal fly ash (FA) and rice husk bottom ash (RA). The results showed that the 45FARA10MSW and 50FA50BSW geopolymers had maximum compressive strengths of 188.78 and 130.94 ksc, respectively. The absorbable geopolymers 45FARA10MSW-AC and 50FA50BSW-AC, produced from waste charcoal-derived AC, exhibited Cu2+ removal performances of 68.5% and 98.3%, respectively. The high adsorption performance was owing to improved physical properties such as the surface area, pore size, and average porosity of the AC products. In summary, absorbable geopolymer products from waste could be a promising green materials for environmental applications.

Preparation of corn starch/acrylic acid/itaconic acid ion exchange hydrogel and its adsorption properties for copper and lead ions in wastewater

In this study, corn starch/acrylic acid/ itaconic acid (CS/AA/IA) hydrogel was prepared by solution polymerization, and then alkaline washed with sodium hydroxide solution to form corn starch/acrylic acid/ itaconic acid (CS/AA/IA) ion exchange hydrogel for the adsorption of copper and lead ions in aqueous solution. The structure and morphology of the hydrogel were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of contact time, initial concentration, temperature, pH, coexisting ions and different water types on the adsorption of Pb2+ and Cu2+ were analyzed by batch adsorption experiments. The CS/AA/IA ion exchange hydrogel reached adsorption equilibrium within 40 min. The maximum adsorption capacities of Pb2+ and Cu2+ fitted by the Langmuir isothermal adsorption model were 869.56 mg/g and 699.31 mg/g, respectively. After five adsorption-desorption cycles, the adsorption capacity of the hydrogel for Pb2+ and Cu2+ remained at 95%. The synthesis method maximized the conversion of –COOH in the hydrogel into the active group –COONa, forming a highly efficient adsorption hydrogel with ion exchange as the main effect. The CS/AA/IA ion exchange hydrogel exhibits high adsorption capacity, fast adsorption efficiency and remarkable regeneration property, and shows potential applications in the field of water treatment.

An all-biopolymer self-assembling hydrogel film consisting of chitosan and carboxymethyl guar gum: A novel bio-based composite adsorbent for Cu2+ adsorption from aqueous solution

A novel bio-based composite adsorbent, all biopolymer self-assembled hydrogel film has been prepared by eco-friendly amalgamating chitosan (CS) and carboxymethyl guar gum (CMGG) biopolymers in water without needing small molecules for cross-linking. Various analysis demonstrated the electrostatic interactions and hydrogen bondings within the network structure are responsible for gelling, crosslinking, and forming a 3D structure. Various experimental parameters were optimized to evaluate the CS/CMGG's potential for removing Cu2+ ions from aqueous solution, including pH, dosage, Cu(II) initial concentration, contact time, and temperature. The pseudo-second-order kinetic and Langmuir isotherm models are highly correlated with the kinetic and equilibrium isotherm data, respectively. Using the Langmuir isotherm model for an initial metal concentration of 50 mg/L at pH 6.0 and 25 °C, the maximum adsorption of Cu(II) was calculated to be 155.51 mg/g. A combination of adsorption-complexation and ion exchange must be involved in Cu(II) adsorption on the CS/CMGG. Five cycles of the loaded CS/CMGG hydrogel regeneration and reuse were successfully achieved without an appreciable difference in Cu(II) removal percentage. Thermodynamic analysis indicated that copper adsorption occurred spontaneously (ΔG°: −2.85 J/mol, 298 K) and exothermically (ΔH°: −27.58 J/mol). A reusable bio-adsorbent for removing heavy metal ions was developed that is eco-friendly, sustainable, and efficient.

Adsorption of Copper and Arsenic from Water Using a Semi-Interpenetrating Polymer Network Based on Alginate and Chitosan.

New biobased hydrogels were prepared via a semi-interpenetrating polymer network (semi-IPN) using polyacrylamide/chitosan (PAAM/chitosan) hydrogel for the adsorption of As(V) or poly acrylic acid/alginate (PAA/alginate) hydrogel for the adsorption of Cu(II). Both systems were crosslinked using N,N'-methylenebisacrylamide as the crosslinker and ammonium persulfate as the initiating agent. The hydrogels were characterized by SEM, Z-potential, and FTIR. Their performance was studied under different variables, such as the biopolymer effect, adsorbent dose, pH, contact time, and concentration of metal ions. The characterization of hydrogels revealed the morphology of the material, with and without biopolymers. In both cases, the added biopolymer provided porosity and cavities' formation, which improved the removal capacity. The Z-potential informed the surface charge of hydrogels, and the addition of biopolymers modified it, which explains the further metal removal ability. The FTIR spectra showed the functional groups of the hydrogels, confirming its chemical structure. In addition, the adsorption results showed that PAAM/chitosan can efficiently remove arsenic, reaching a capacity of 17.8 mg/g at pH 5.0, and it can also be regenerated by HNO3 for six cycles. On the other hand, copper-ion absorption was studied on PAA/alginate, which can remove with an adsorption capacity of 63.59 mg/g at pH 4.0, and the results indicate that it can also be regenerated by HNO3 for five cycles.

Experimental and theoretical study of 2-mercaptopyridine as an effective eco-friendly inhibitor for copper in aqueous NaCl

The high-efficiency and non-toxic inhibitors for copper and its alloys are of great importance for reducing the corrosion rate of copper in aggressive solutions. In this work, the inhibition effect of 2-mercaptopyridine (2-MP) for copper in NaCl aqueous solution was investigated by experiment and theoretical calculation. The comprehensive experimental results showed that the surface of the copper sample was still smooth after 72 h immersion in NaCl solution containing 0.75 g/L 2-MP inhibitor, and the inhibition efficiency could reach 93.27 %. Meanwhile, the CuN/SCu bonds were detected by X-ray photoelectron spectroscopy and Raman spectroscopy, indicating that the 2-MP inhibitor could adsorb on the copper surface directly. The adsorption of copper by 2-MP is compatible with the Langmuir isotherm adsorption. The difference in reactivity between 2-MP and 4-MP was analyzed by quantum chemistry calculation, while molecular dynamics (MD) simulation results showed that 2-MP has better inhibition performance than 4-MP. Furthermore, the compactness and hydrophobicity of the 2-MP molecular layer were increased with a rise in 2-MP concentration, which effectively obstructed the diffusion of the water molecular and prevented the corrosive medium contact with the copper surface.

Improved laccase production by Trametes versicolor using Copper-Glycyl-L-Histidyl-L-Lysine as a novel and high-efficient inducer.

A highly efficient strategy using Copper-Glycyl-L-Histidyl-L-Lysine (GHK-Cu) as a novel inducer was developed to enhance laccase production by Trametes versicolor. After medium optimization, laccase activity increased by 12.77-fold compared to that without GHK-Cu. The laccase production of 1113.8U L-1 was obtained by scaling-up culture in 5-L stirring tank. The laccase production induced by CuSO4 was poorer than that of GHK-Cu at the same mole concentration. GHK-Cu could increase the permeability of cell membrane with less damage, and it facilitated the adsorption, accumulation, and utilization of copper by fungal cells, which was beneficial for laccase synthesis. GHK-Cu induced better expression of laccase related genes than that of CuSO4, resulting in higher laccase production. This study provided a useful method for induced production of laccase by applying GHK chelated metal ion as a non-toxic inducer, which reduced the safety risk of laccase broth and provided the potential application of crude laccase in food industry. In addition, GHK can be used as the carrier of different metal ions to enhance the production of other metalloenzymes.

Isotermal Adsorpsi Ion Tembaga (II) Menggunakan Arang Tongkol Jagung (Zea mays L.) Teraktivasi Kalium Permanganat

Corn cobs which generally only become waste can be processed into activated carbon and used for the absorption of heavy metals, such as copper(II) ions. This study aims to determine the morphology of corn cobs charcoal after activation, determine the isothermal adsorption model of copper (II) metal ions on corncob-activated carbon, and then determine the adsorption capacity of copper (II) metal ions on corncob-activated carbon. The morphology of the corncob-activated charcoal obtained was analyzed using Scanning Electron Microscopy (SEM). Isothermal adsorption of copper (II) ions was carried out with various concentrations of copper (II) ions of 5, 10, 20, 50, and 100 ppm. The results of the analysis using SEM showed that the surface shape of the corncob-activated charcoal is regular and has pores with a pore diameter obtained in the range between 1.08-1.26 m and 1.38-1.59 m. The mechanism of adsorption of copper (II) ions by corncob-activated charcoal using KMnO4, following the Freundlich isothermal model with a value of R2 0.9993 with an adsorption capacity of 51 x 10-4 mmol/L. The utilization of activated carbon from corn cobs that are activated by potassium permanganate is very effective for adsorbing copper metal ion pollutants through an adsorption mechanism on the surface of activated carbon.

One-pot synthesis of dual-sites adsorbent based on recycling spent Lithium-ion batteries: Matter cycle, orderly grafting, and copper adsorption

Waste carbon residue (WCR), a hazardous solid waste discharged from spent lithium-ion batteries recovery industry, have caused serious environmental pollution. In this work, WCR with ferric impurity was recycled as dual-sites adsorbents for efficient removal of Cu2+ in wastewater. The adsorbent, sulfhydryl grafting Fe(OH)3/graphite (SFG), was synthesized by one-pot method. In this process, the ferric impurity was transformed into amorphous Fe(OH)3 in-situ, and sulfhydryl (-SH) was orderly grafted on adsorbent surface by regulation of 3-(Trimethoxysilyl) propyl methacrylate (TPM). In the regulation, TPM combined adsorbent surface and cysteine molecule by its inorganic and organic ends. Furthermore, the filtrate and adsorbent could be reused many times. The adsorption kinetics followed the pseudo-second-order model, the isotherm fitted better with the Freundlich isotherm model, which indicated that the adsorption of Cu2+ on SFG was a multilayer and heterogeneous chemisorption process. Langmuir maximum adsorption capacity of Cu2+ was 185.2 mg/g which was higher than many similar adsorbents. Adsorption mechanisms were explored by material characterizations and DFT calculations. The –OH groups of Fe(OH)3 reacted with Cu2+ via ion-exchange, the sulfur atom in –SH groups chelated with Cu2+ by transferring electrons to Cu atom. Synergistic effect of Fe(OH)3, sulfhydryl, and TPM provided SFG with outstanding adsorptive performance to Cu2+ contamination.

The Role of Surface Functional Groups of Iron Oxide, Organic Matter, and Clay Mineral Complexes in Sediments on the Adsorption of Copper Ions

Heavy metal pollution is a global problem affecting the environment and human health. Sediment is the source sink of heavy metals in water. Under certain circumstances, the migration of heavy metals will cause water pollution. Therefore, it is of great significance to study sediment composition and composite complexes in the migration and transformation of heavy metals. To understand the adsorption mechanisms of composite complexes and improve the theoretical understanding of adsorption in multi-component complex systems, this study explored the characteristics and rules of Cu adsorption to organic–inorganic, inorganic minerals, and iron-oxide–clay complexes in the estuary sediments of the Dianchi Lake. The Langmuir and Freundlich isotherm models were used for Cu adsorption experiments on three complexes to study their adsorption kinetics. X-ray diffraction and Fourier transform infrared spectroscopy characterized the samples before and after adsorption. The relationship between adsorption capacity and sediment composition was analyzed through redundant analyses. The results showed that the Freundlich isothermal model was better than the Langmuir model in describing the adsorption behavior of the adsorbents. The contribution of iron and aluminum oxides to Cu adsorption was more than that of organic matter. The organic–inorganic complexes functional groups involved in copper adsorption are the most, which resulting in a higher adsorption capacity. The organic matter removal (organic degradation in sediment) will reduce the polar functional groups and reduce silicide activity, leading to heavy metal desorption and re-entry into the water body.

Periodic DFT study on heavy metals Cu(II) and Pb(II) atoms adsorption on Na-montmorillonite (010) edge surface

Heavy metal (HM) pollution is of great concern currently because it has been recognized as a potential threat to air, water,and soil. Adsorption is one of the most effective strategies for removing heavy metals. Montmorillonite as the adsorbent with a low cost and high thermal stability has received much attention. The adsorption of heavy metal Copper [Cu(II)] and Plumbum [Pb(II)] atoms on Na-montmorillonite hydroxylated (010) edge surface was analyzed using the generalized gradient approximation and density functional theory in the supercell technique. The coverage dependence of the adsorption structure and energetics was systematically investigated for a wide range of coverage from 0 to 1.0 monolayer (ML). Among all the possible adsorption sites, the most stable adsorption site for Cu(II) atom was a three-fold hollow site while the most favorable adsorption site for Pb(II) atom was a three-fold hollow site and followed by a two-fold bridge site. The adsorption energy increased with increasing coverage of Pb(II) atoms, indicating higher stability of surface adsorption and a tendency for the formation of adsorbate island clusters with increasing coverage. However, the adsorption energy of Cu(II) atoms decreased with increasing coverage. In the coverage range of 0 < Θ ≤ 0.5 ML the recovery capacity of the Na-montmorillonite for the heavy metal atoms was in the order of Cu(II)>Pb(II), while the recovery capacity of the Na-montmorillonite in the coverage range of 0.5 < Θ ≤ 1 ML was in the order of Pb(II)>Cu(II). The other aspects of the Cu(II) and Pb(II)/Na-montmorillonite (010) systems, including adsorption geometry, differential charge distribution, and electronic density of states were also studied and discussed in detail.

Regeneration of copper-loaded pine bark biochar using simultaneous bio-sulfide precipitation of copper

Abstract This research investigated adsorption of copper from aqueous solution onto the pine bark biochar, removal of adsorbed copper by bio-sulfide precipitation, and simultaneous regeneration of pine bark biochar adsorbent. A sulfidogenic reactor was established and operated under anaerobic conditions. During the sulfidogenic phase, COD:SO42− was gradually increased from 24:1 to 4:1. Use of sulfide-rich effluent from bio-sulfide reactor at neutral pH yielded above 99% copper removal from the aqueous solution. In the experiment's second stage, pine bark biochar was prepared through slow pyrolysis at 650 °C from pine bark residue that had a carbon content of 81% and a surface area of 368 m2/g. This biochar was then used in subsequent experiments. Initially, copper was adsorbed onto the biochar under neutral pH at contact time of 6 h. Maximum biochar adsorption capacity of 106 mg/g of copper was obtained. Finally, biochar was regenerated by precipitating the adsorbed copper as copper sulfide using sulfide-rich effluent from the sulfidogenic reactor. Complete recovery of adsorbed copper from biochar as copper sulfide precipitates were obtained was also confirmed by EDX-SEM analysis of biochar and precipitates. Regenerated biochar could be reused as an adsorbent in the subsequent adsorption cycle.

One-pot synthesis of ion-imprinted three-dimensional porous material based on graphene oxide for the selective adsorption of copper(II)

Molecularly imprinted polymers (MIPs) are synthetic polymers with predetermined selectivity for a given analyte. One major problem associated with MIPs is the inaccessibility of a large fraction of the recognition sites that remain buried within the polymeric matrix. To address this problem, the high selectivity imparted by the imprinting technique and the porosity of three-dimensional (3D) graphene oxide (GO)-based porous materials were utilized in this work to prepare a 3D GO-based Cu(II)-ion-imprinted material (hereafter denoted as IIM) via one-pot reactions of GO, chitosan (CS), and glutaraldehyde in the presence of Cu(II). Results of equilibrium binding experiments show that IIM has a high template-ion binding capacity (1.75 mmol g−1) and good imprinting factor (2.19). Further, results of selectivity tests indicate that IIM has a high Cu(II)-recognition ability. IIM also has a fast binding rate and satisfactory reusability. In addition, the Langmuir isotherm model was well fitted with the experimental data, indicating the monolayer adsorption of Cu(II) ions. The present work provided a convenient approach to prepare 3D GO-based imprinted materials that are promising for enrichment or recycling of target compounds from wastewater.

A Carbonized Zeolite/Chitosan Composite as an Adsorbent for Copper (II) and Chromium (VI) Removal from Water.

To address Cu(II) and Cr(VI) water pollution, a carbonized zeolite/chitosan (C-ZLCH) composite adsorbent was produced via pyrolysis at 500 °C for two hours. C-ZLCH was characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and zeta potential measurements. The batch experiments were performed by varying the initial pH, concentration, and contact time. The optimal pH values for Cu(II) and Cr(VI) were 8.1 and 9.6, respectively. The highest adsorption capacities for Cu(II) and Cr(VI) were 111.35 mg/g at 60 min and 104.75 mg/g at 90 min, respectively. The effects of chemicals such as sodium (Na+), glucose, ammonium (NH4+), and acid red 88 (AR88) were also studied. Statistical analysis showed that sodium had no significant effect on Cu(II) removal, in contrast to Cr(VI) removal. However, there was a significant effect of the presence of glucose, ammonium, and AR88 on both Cu(II) and Cr(VI) removal. The adsorption isotherm and kinetic models were fitted using Langmuir and pseudo-second-order models for Cu(II) and Cr(VI), respectively.

Environmentally friendly starch/alginate aerogels for copper adsorption from aqueous media. A microstructural and kinetic study

This work investigated the synthesis and characterization of alginate/starch porous materials and their application as copper ions adsorbents from aqueous media. Initially, pregel aqueous solutions with different biopolymer concentrations (1, 3, and 5% w/w) and alginate contents (25, 50, and 75% w/w) were prepared. Hydrogel formation was performed by internal and external gelation methods. Finally, the drying step was done via CO2 sc leading to aerogels and via freeze-drying leading to cryogels. Process parameters influence on the final properties of materials was evaluated by BET isotherms, SEM, EDS, and TGA. Regardless the gelation method applied, interesting materials with meso- and macro-pore structure were prepared from pregel mixtures with 3% w/w biopolymer concentration and an alginate content of only 25% w/w. Low alginate content reduces the final cost of the materials. Concerning copper removal, the adsorption data were well fitted to the pseudo-second order kinetic model for aerogels and cryogels, showing aerogels the highest adsorption capacity (40 mg/g) and removal efficiency (∼ 92%). Materials demonstrated excellent reusability throughout five consecutive adsorption/desorption cycles. Hence, environmentally friendly materials with a high practical value as low-cost bioadsorbents were synthesized, having great performance in the removal of copper ions from aqueous solution.

Preparation of High Specific Surface Thiourea Modified Peanut Shell Carbon and Adsorption of Tetracycline and Copper

High activity nitrogen and sulfur co-doping high specific surface-modified peanut shell carbon PBC-NS was prepared through one-step carbonization using thiourea and phosphoric acid as modifiers. The TC/Cu(Ⅱ) adsorption characteristics of peanut shell carbon in single and mixed-adsorption systems were discussed, and the enhancement effect and mechanism of modification on TC/Cu(Ⅱ) adsorption were studied. The results showed that the modified peanut shell carbon PBC-NS successfully introduced nitrogen-sulfur functional groups such as Pyridinic N, Graphitic N, C- S-C, and -SH, and the modified specific surface area was as high as 1437 m2·g-1, which was 2.6 times higher than that before modification. The maximum adsorption capacities of modified peanut shell carbon PBC-NS for single-system TC and Cu(Ⅱ) were 585 mg·g-1 and 21.2 mg·g-1, respectively, which were 2.6 times and 2.7 times higher than those before modification. The saturated adsorption capacities of TC and Cu(Ⅱ) in the system were increased by 13 mg·g-1 and 6.8 mg·g-1 compared with that in the single system. The adsorption capacity of PBC-NS for TC and Cu(Ⅱ) could still reach 66% and 70% of the initial adsorption capacity after four times of repeated use. Isotherm fitting and modern spectroscopic analysis indicated that the substantial increase in the adsorption capacity of TC/Cu(Ⅱ) on PBC-NS by modification was mainly attributed to the combined effect of chemical chelation of nitrogen-sulfur active functional sites and pore filling caused by high specific surface area. These results indicated that thiourea/phosphoric acid chemical modification could effectively improve the adsorption capacity of peanut shell carbon for TC/Cu(Ⅱ), which can provide a new idea for the structural regulation of mixed-pollution biochar with high adsorption capacity and adsorption treatment of TC/Cu(Ⅱ) water pollution.