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Natural estrogen conjugates play important roles in municipal wastewater treatment plant (WWTP), but their deconjugation potentials are poorly understood. This work is the first to investigate the relationships between the enzyme activities of arylsulfatase/β-glucuronidase and deconjugation potentials of natural estrogen conjugates. This work led to three important findings. First, the enzyme activity of β-glucuronidase in sewage is far higher than that of arylsulfatase, while their corresponding activities in activated sludge were similar. Second, a model based on β-glucuronidase could successfully predict the deconjugation potentials of natural estrogen glucuronide conjugates in sewage. Third, the enzyme activity of arylsulfatase in sewage was too low to lead to evident deconjugation of sulfate conjugates, which means that the deconjugation rate of estrogen sulfates can be regarded as zero. By comparing their theoretical removal based on enzyme activity and on-site investigation, it is reasonable to conclude that reverse deconjugation of estrogen conjugates (i.e., conjugation of natural estrogens to form conjugated estrogens) likely exist in WWTP, which explains well why natural estrogen conjugates cannot be effectively removed in WWTP. Meanwhile, this work provides new insights how to improve the removal performance of WWTP on natural estrogen conjugates. SYNOPSIS: This work is the first to show how arylsulfatase/β-glucuronidase could affect deconjugation of natural estrogen conjugates and possible way to enhance their removal in wastewater treatment plant., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ibuprofen and acetaminophen as two anti-fever agents have been widely used in human. Due to lack of full understanding, this work firstly summarized their occurrence and fate in municipal wastewater treatment plants (WWTPs) across 30 countries. The respective influent concentrations of ibuprofen and acetaminophen were not detected (ND)-39,830,000 and ND-66440000 ng/L, while their corresponding respective effluent concentrations were ND-58710 and ND-90500 ng/L. The removal efficiencies of ibuprofen and acetaminophen in municipal WWTPs were 6.5-100 % and 14.3-100 % with respective average removal efficiencies of 87.6 % and 94.7 %. There have been many batch studies on ibuprofen biodegradation with k bio values available, while such investigation for acetaminophen was very limited. The theoretically calculated removal efficiency of ibuprofen with k bio agreed well with that of the observed average removal efficiency of on-site investigations on full-scale WWTP, which was quite different from natural estrogens and some other emerging contaminants. One possible reason is that conjugated ibuprofen could be easily cleaved and the cleavage step gives little effect on the biodegradation of ibuprofen. Due to extremely high concentrations of ibuprofen and acetaminophen in influent of municipal WWTP, their concentration levels in effluent likely high enough to pose adverse effects on some aquatic organisms. To protect water environment, advanced treatment is necessary to further remove residue ibuprofen and acetaminophen in the effluent. To the best of our knowledge, this is the systematical summarization on the occurrence and fate of ibuprofen and acetaminophen in municipal WWTP as well as their potential effect on aquatic organisms, which addressed known knowledge and unknowns to be further investigated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Bisphenol analogues (BPs) and natural estrogens (NEs) as two important groups of endocrine-disrupting compounds (EDCs) in drinking water treatment plants (DWTPs) have been hardly investigated except bisphenol A (BPA) and three major NEs including estrone (E1), 17β-estradiol (E2) and estriol (E3). In this study, a GC-MS analytical method was firstly established and validated for trace simultaneous determination of ten BPs and twelve NEs in drinking water, which included BPA, bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bsiphenol F (BPF), bsiphenol P (BPP), bisphenol S (BPS), bisphenol Z (BPZ), bisphenol AF (BPAF), bisphenol AP (BPAP), E1, E2, E3, 17α-estradiol (17α-E2), 2-hydroestrone (2OHE1), 16hydroxyestrone (16α-OHE1), 4-hydroestrone (4OHE1), 2-hydroxyesstradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 17-epiestriol (17epiE3), 16-epiestriol (16epiE3) and 16keto-estraiol (16ketoE2). This investigation showed that eighteen out of twenty-two targeted compounds were detected in drinking source waters of eight DWTPs with concentrations ranging from not detected to 142.8 ng/L. Although the conventional treatment process of DWTP could efficiently remove both BPs and NEs with respective removal efficiencies of 74.1%-90.9% and 74.5%-100%, BPA, BPS, BPE, BPZ, E1, 2OHE1, and 2OHE2 were found in the finished drinking waters. Chlorination could remove part of BPs and NEs, but the efficiency varied greatly with DWTP and the reason was unknown. In the finished drinking waters of eight DWTPs, the highest chemically calculated estrogen equivalence (EEQ) derived from BPs and NEs was up to 6.11 ngE2/L, which was over 22 times that could do harm to zebrafish, indicating a potential risk to human health. Given the fact that many chlorination products of BPs and NEs likely have higher estrogenic activities, the estrogenic effect of BPs and NEs in finished drinking water should be accurately examined urgently with the inclusion of BPs, NEs as well as their main chlorinated by-products. This study shed new light on the occurrence, removal, and potential estrogenic effects of BPs and NEs in DWTPs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This work shows the existence of both 17-ethinylestradiol-3-sulfate (EE2-3S) and 17-ethinylestradiol-3-glucuronide (EE2-3G) in seven municipal WWTPs with substantial concentrations (n.d-50.10 ng/L). The calculated removal efficiencies of 17-ethinylestradiol (EE2) in the seven municipal WWTPs ranged from 40.8%-100% with an average removal efficiency of 83.3%. However, upon the inclusion of EE2 concentration transformed from EE2-3S and EE2-3G, the corresponding removal efficiencies were increased to 91.4%-100% with an average removal efficiency of 97.3%. This work is the first to clearly illustrate that EE2 conjugates in raw wastewater could greatly underestimate the removal effectiveness of municipal WWTPs on EE2, indicating the importance of the EE2 conjugates in municipal wastewater having been hardly paid with attention. The EE2-derived estrogen equivalence (EEQ) values in the effluents of seven WWTPs ranged from 0 to 0.98 ng E2/L having an average level of 0.45 ng E2/L, which were relatively low. However, upon the inclusion of EE2 transformable from EE2-3S and EE2-3G in effluents, the EE2-derived EEQ values in effluents would be increased to 0.77-4.85 ng E2/L having an average level of 2.71 ng E2/L, which clearly suggested that ignorance of EE2 conjugates in effluent would largely underestimate EE2's environmental risk to receiving water bodies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Organophosphorus esters (OPEs), one kind of the emerging contaminants with high frequency of detection, is rather refractory in natural environment, thus posing great threat to human health. This study investigated the feasibility and mechanism of tris(2-chloroethyl) phosphate (TCEP) degradation in thermally activated persulfate (TAP) system. Influence of impact factors, such as PDS dosage, temperature, initial pH, and presence of natural water matrix (Cl - , NO 3 - , H 2 PO 4 - , NH 4 + , humic acid), were evaluated. Results showed that 100% degradation of TCEP can be achieved in TAP system in 40 min at 60 °C. SO 4 ·- as the dominant oxidant for TCEP degradation was proved by quenching experiment and verified by EPR analysis. Alkaline condition exerted great inhibitory effect by affecting the constituents of oxidative radicals. It is suggested that Cl - and H 2 PO 4 - at lower dosages promoted the degradation by stimulating ·OH production and forming oxidative radicals with better selectivity. Intermediates identified by high resolution mass spectrometer was suggested less toxic than TCEP by ECOSAR program. Meanwhile, the illustrated oxidation mechanism mainly involved radical attack at CCl bond and cleavage of CO bond, as further confirmed by frontier electron density calculation and wavefunction analysis. Moreover, cyclic degradation of TCEP indicated the constant release of SO 4 ·- in 450 min, suggesting high efficiency and stability of PDS in TAP system. Four selected OPEs achieved complete removal in TAP system and their degradation discrepancy was further discussed based on the distinctive structures. Altogether, TAP technology can be used as an efficient method in TCEP removal with great potential for application., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

As a synthetic estrogen, 17α-ethynylestradiol (EE2) has been known to show the strong estrogenic potency. This work critically reviewed the occurrence and removal of EE2 in municipal wastewater treatment plants (WWTPs). Based on the on-site investigations from 282 municipal WWTPs across 29 countries, the concentrations of EE2 in influent and effluent ranged from n.d-7890 and n.d-549 ng/L, with respective average concentrations of 78.4 and 12.3 ng/L. The average effluent concentration of EE2 was more than 61 times higher than the reported lowest-observed-effect concentration, indicating an urgent need for removing EE2 in WWTPs. The calculated removal efficiencies of EE2 in different wastewater treatment processes varied from -100%-100%. Averagely, 47.5% of EE2 was removed in the primary treatment process, 55.3% by biological filter treatment, 59.4% by lagoon and 71.5% by activated sludge process. The observed removal of EE2 in municipal WWTP could be mainly attributed to adsorption and biodegradation, which could be predicted according to its solid-water distribution coefficients and biodegradation rate constants. However, it should be noted that the predicted removal of EE2 was found to deviate from the in-plant observation, likely attributing to the existence of EE2 conjugates in raw municipal wastewater. Therefore, the effect of EE2 conjugates on the EE2 removal in WWTPs should be taken into account in future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Endocrine disrupting compounds (EDCs) are well known emerging contaminants, which have the capacity to elicit negative effects on endocrine systems of both humans and wildlife. As the conventional wastewater treatment plants cannot stably remove these EDCs, post-treatment with advanced chemical oxidation methods such as ozonation are proven effective to further remove EDCs, but this additional treatment increase the wastewater treatment cost, which is impractical for worldwide application. To find potential alternative effective method, this work presents the importance of EDCs conjugates. Specifically, two important facts are described: 1) concentrations of EDCs conjugates in raw municipal wastewater vary with temperature, and their existence results in underestimated removal performance of WWTPs; 2) Strategies to enhance the cleavage rates of EDCs conjugates are most effective to improve the observed removal performance of conventional WWTPs on EDCs. Further work should be performed to check whether effective solutions can be found to increase their cleavage rates., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Zinc (Zn 2+ ) and cadmium (Cd 2+ ) in water pose serious threats to human health and the environment. In search for a more effective treatment technology, we prepared a type of carboxymethyl cellulose (CMC) bridged chlorapatite (CMC-CAP) nanoparticles and tested the material for removal of Zn 2+ and Cd 2+ from water. CMC macromolecules were attached to CAP by bidentate bridging and hydrogen bonding, preserving the high adsorption capacity of CAP nanoparticles while allowing for easy gravity-separation of the nanoparticles. CMC-CAP showed rapid adsorption kinetics and 22.8% and 11.2% higher equilibrium uptake for Zn 2+ and Cd 2+ , respectively, than pristine CAP. An extended dual-mode isotherm model, which takes into account both sorption and chemical precipitation, provided the best fits to the sorption isotherms, giving a maximum Langmuir sorption capacity of 141.1 mg g -1 for Zn 2+ and 150.2 mg g -1 for Cd 2+ by CMC-CAP. Na + at up to 5 mM showed modest effects on the uptake of the heavy metals, while 2-5 mM of Ca 2+ exerted notable inhibitive effects. Dissolved organic matter (up to 5 mg L -1 as TOC) inhibited the Zn 2+ uptake by 16.5% but enhanced the Cd 2+ removal by 8.6%. Material characterizations and surface binding analyses revealed that ion exchange, surface precipitation, and surface complexation were the removal mechanisms for the heavy metals. This study demonstrates stabilizer bridging may serve as a convenient strategy to facilitate water treatment uses of nanoparticles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Recently, sulfate radical-based advanced oxidation processes (SR-AOPs) have been studied extensively for the removal of pollutants, however, few researches focused on the activation of bisulfite by nanoscale zerovalent iron (nZVI), especially, surface reaction mechanism and sulfate radical-mediated degradation pathway have not been elucidated in detail. In this study, influencing factors, the kinetics, transformation pathway and mechanism of triphenyl phosphate (TPHP) degradation in the nZVI/bisulfite system were systematically discussed. Compared with Fe 2+ , nZVI was found to be a more efficient and long-lasting activator of bisulfite via gradual generation of iron ions. The optimal degradation efficiency of TPHP (98.2%) and pseudo-first-order kinetics rate constant (k obs  = 0.2784 min -1 ) were obtained by using 0.5 mM nZVI and 2.0 mM bisulfite at the initial pH 3.0. Both Cl - and NO 3 - inhibited the degradation of TPHP and the inhibitory effect of Cl - was stronger than that of NO 3 - due to the higher reaction rate of Cl - with •SO 4 - . Furthermore, SEM, XRD and XPS characterization revealed that a thin passivation layer (Fe 2 O 3 , Fe 3 O 4 , FeOOH) deposited on the surface of fresh nZVI and a few iron corrosion products generated and assembled on the surface of reacted nZVI. Radical quenching tests identified that •SO 4 - was the dominant reactive oxidative species (ROS) for TPHP removal. Based on HRMS analysis, six degradation products were determined and a sulfate radical-mediated degradation pathway was proposed. In a word, this study revealed that the nZVI/bisulfite system had a great potential for the TPHP elimination in waterbody., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A multifunctional magnetic composite (0.3Ma-MgMnLDO-a) with the function of Cd 2+ adsorption and paracetamol (PAM) degradation was successfully fabricated. Surface morphology showed that Fe 3 O 4 agglomeration was overcome on composite. The composite had high specific surface area of 105.32 m 2  g -1 and saturation magnetization of 40 emu∙g -1 . 0.3Ma-MgMnLDO-a could reach Cd 2+ adsorption equilibrium within 5 min with 99 % removal rate. The maximum adsorption capacity was 3.76 mmol·g -1 (422.62 mg g -1 ), which apparently higher than that of Fe 3 O 4 -a and MgMnLDO-a, indicating that the Fe/Mn synergism results in excellent ability for Cd 2+ adsorption. Moreover, the composite could efficiently activate peroxymonosulfate (PMS) to rapid degrade PAM with the highest first-order rate constants (k obs  = 0.116 min -1 ) and total organic carbon (TOC) removal rate (67.7 %), which also due to the contribution of Fe/Mn synergism in PMS activation. The cycling of Mn III /Mn IV and Fe II /Fe III played an important role in activating PMS to generateO 2 -• , 1 O 2 and OH for degradation. The composite exhibited both stable adsorption and catalytic performance on wide pH (3-9) and five reuse cycles. Notably, there was mutual promotion between Cd 2+ and PAM adsorption, while the coexistence of Cd 2+ had slight inhibition on PAM degradation. Overall, the magnetic composite had promising application for purifying heavy metals and pharmaceuticals., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Advanced oxidation processes (AOPs), such as hydroxyl radical (•OH) and sulfate radical (•SO 4 - ) mediated oxidation, are proved to be effective methods to remove the organophosphorus esters (OPEs) in wastewater effluents. However, few studies have reported about the bimolecular reaction rate constants between free radicals (•OH and •SO 4 - ) and OPEs. This issue was solved by selecting three OPEs as model compounds, the oxidation of these OPEs in UV/H 2 O 2 and UV/K 2 S 2 O 8 process were studied. Tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(2,3-dichloropropyl) phosphate (TDCPP) can hardly be oxidized through direct irradiation methods using UV lamp, with the oxidation rate less than 30% after 7 h' irradiation. However, TCEP, TCPP, and TDCPP undergo degradation via UV/H 2 O 2 and UV/K 2 S 2 O 8 processes easily, the oxidation rates increased with increasing H 2 O 2 and K 2 S 2 O 8 dosage. The oxidation rates of three OPEs have been studied using competition experiments in the UV/H 2 O 2 and UV/K 2 S 2 O 8 processes. The bimolecular reaction rate constants of TCEP, TCPP and TDCPP with •OH were 2.50 × 10 10 , 3.95 × 10 10 and 2.94 × 10 10 respectively; while •SO 4 - were 3.00 × 10 7 , 1.82 × 10 7 and 2.06 × 10 7 respectively. Results showed that the simplified kinetic model involves only steady state concentration of free radicals and the molecular reaction rate contents are available for calculating the oxidation rates of OPEs in ultrapure water., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Antibiotics have drawn much attention as their wide usage in humans and animals may result in microbial resistance, which is a huge threat to humans' health. Studies on the occurrence and removals of antibiotics in wastewater treatment plants have been widely performed, but very few covered their main acetylated metabolites. This study developed an effective analytical method for the trace determination of four sulfonamides and three acetylated metabolites in municipal wastewaters, which was validated by linearity (R 2  > 0.995), sensitivity (limit of quantification, LOQ < 0.78 ng/L), recovery (77.7%-148.1%) and precision (relative standard deviation, RSD < 9.6%). All sulfonamides and their acetylated metabolites were detected in municipal wastewaters including influent, primary settling tank and effluent. Removal performances of sulfapyridine (SP), sulfadiazine (SDZ), sulfamethoxazole (SMZ), and N 4 -acetyl sulfadiazine (AC-SDZ) in the municipal wastewater treatment plant were moderate or excellent, whereas the corresponding removals of sulfamethazine (SM2), N 4 -acetyl sulfapyridine (AC-SP), and N 4 -acetyl sulfamethazine (AC-SM2) were poor. The calculated poor removal of SM2 might be attributed to its fluctuation in raw wastewater, whereas the poor removals of AC-SP and AC-SM2 may be due to re-transformation from their parent sulfonamides. Our results showed that monitoring of acetylated sulfonamides in municipal wastewater is important for two reasons. One is that acetylated metabolites are good biomarkers for wastewater-based epidemiology when they are combined with their corresponding parent sulfonamides. The other is that the potential risk of sulfonamides in effluent to the natural environment cannot be accurately evaluated unless their acetylated metabolites are also accounted. This report is the first to address the potential risk of acetylated sulfonamides in effluent of wastewater treatment plants., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Emerging pollutants introduced into surface water pose potential hazards to the safety of drinking water. In this study, the removal performance of three emerging compounds (exemplified by caffeine, diclofenac and octylphenol, with different physico-chemical properties) from synthetic water and source water by combining activated carbon (AC) adsorption and nanofiltration (NF) membrane processes was evaluated and analyzed. Results from synthetic water showed that the adsorption isotherms modeled well with the Langmuir equation. The removal performance of target compounds by AC-NF system was more remarkable than that of NF-AC combination. In the source water system, the integrated AC-NF process with coagulation pretreatment (the alum dosage of 60 mg/L) achieved satisfactory performance (the removal efficiencies of three target compounds reached > 95%). Results showed the electrostatic interaction and pollutant hydrophobicity determined the behavior and the fate of selected PPCPs/EDCs during the sequential treatment process of coagulation, activated carbon adsorption, and NF membrane separation. Finally, the AC and NF membranes were analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy to understand the mechanisms, i.e. electrostatic and hydrophobic effects on the total removal process. It suggests that the integrated AC-NF process with coagulation pretreatment should be a feasible approach for removing emerging compounds in waterworks., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The heavy metal ion adsorption performance of birnessite (a layer-structured manganese oxide) can be enhanced by decreasing the Mn average oxidation state (Mn AOS) and dissolution-recrystallization during electrochemical redox reactions. However, the electrochemical adsorption processes of heavy metal ions by tunnel-structured manganese oxides are still enigmatic. Here, tunnel-structured manganese oxides including pyrolusite (2.3 Å × 2.3 Å tunnel), cryptomelane (4.6 Å × 4.6 Å tunnel) and todorokite (6.9 Å × 6.9 Å tunnel) were synthesized, and their electrochemical adsorptions for Cd 2+ were performed through galvanostatic charge-discharge. The influence of both supporting ion species in the tunnel and tunnel size on the electrochemical adsorption performance was also studied. The adsorption capacity of tunnel-structured manganese oxides for Cd 2+ was remarkably enhanced by electrochemical redox reactions. Relative to K + in the tunnel of cryptomelane, the supporting ion H + was more favorable to the electrochemical adsorption of Cd 2+ . With increasing initial pH and specific surface area, the electrochemical adsorption capacity of cryptomelane increased. The cryptomelane electrode could be regenerated by galvanostatic charge-discharge in Na 2 SO 4 solution. Due to the differences in their tunnel size and supporting ion species, the tunnel-structured manganese oxides follow the order of cryptomelane (192.0 mg g -1 ) > todorokite (44.8 mg g -1 ) > pyrolusite (13.5 mg g -1 ) in their electrochemical adsorption capacities for Cd 2+ ., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Nanoscale zero-valent iron (nZVI), an environmentally benign material, has been used to remove heavy metals and metalloids from the aqueous phase because of its high reactivity and abundant reactive sites. To improve the stability of nZVI, nanoscale zero-valent iron supported by amino-modified biochar (ZVIA-BC) was prepared and characterized. Its ability to remove heavy metals and metalloid was investigated. Fourier transform infrared spectroscopy analyses showed that the amino group was chemically bound to the functional groups of biochar. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction revealed that zero-valent iron was loaded on the biochar surface. High-resolution transmission electron microscope images showed that the particle size of iron was ∼50 nm and the particles consisted of roughly spherical cores covered with a shell that was uniformly 2- to 3-nm thick. Furthermore, measuring the zeta potentials at various pH values indicated that the iso-electric points occurred within the pH range of 7.50 to 7.56. Additionally, heavy metals and metalloids, including Cd(II), Ni(II), Cu(II), Cr(VI) and As(V) adsorption isotherms, on ZVIA-BC were significantly nonlinear, and ZVIA-BC exhibited a superior ability to remove these heavy metals and metalloids, especially for Cr(VI) and As(V). Characterization with high-resolution XPS revealed that reduction of heavy metals and metalloids occurred on the surface of ZVIA-BC. The main mechanisms for removal were reduction, complexation, co-precipitation, and electrostatic interaction., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

This work aims at preparing oil spill sorbent (TCS, Trichoderma viride-modified corn stalk) through solid-state fermentation of corn stalk by Trichoderma viride. Single-factor experiments, including the effect of modification time, solid-liquid ratio of modification and modification temperature, and adsorption experiments simulating oil spill condition, were carried out. The results indicated that the maximum oil adsorption of TCS, 13.84 g x g(-1), could be obtained under the conditions of 6 days of modification, with a solid-liquid ratio of 1:4 and a modification temperature of 25 degrees C. This oil absorption was 110.33% of that of the raw material (RCS, Raw Corn Stalk). Comparing RCS and TCS by means of Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD), the results separately showed that TCS had rougher surface, lower cellulose content and higher instability, which explains the increase of oil absorption. Also, the component analysis indicated that bio-modification could reduce the contents of celluloses and hemicelluloses from corn stalk. Besides, sorption kinetics and oil retention performance test showed that, TCS, which could reach adsorption equilibrium after 1 h of 80 r x min(-1) oscillating, had fast oil adsorption rate, and it also had good oil retention performance, which could keep 74. 87% of the initial adsorption rate when trickling 10 min after reaching adsorption equilibrium.

Corn stalk was modified using graft copolymerization to produce absorbent (AGCS), which was characterized by elemental analysis, fourier transform infrared, X-ray diffraction, solid-state CP/MAS (13)C NMR spectra, thermogravimetric analysis and differential scanning calorimeter. AGCS, having cyano group (-CN) after grafted successfully, exhibits more high adsorption potential for Cd(II) than unmodified forms. The efficiency of AGCS for removal of cadmium ions was evaluated. Factors affecting Cd(II) adsorption such as pH value and adsorbent dosage were investigated. More than 90% removal was achieved at pH 3.0-7.0 and the adsorption increased from 16.0% to 99.2% with increase of adsorbent dose. In addition, two isotherm models, namely, Langmuir and Freunlich were also analyzed to determine the best fit equation for adsorption of Cd(II) on AGCS., ((c) 2010 Elsevier Ltd. All rights reserved.)