Adsorption performance and mechanisms of mercaptans removal using core-shell AC-based adsorbents.pptx

To investigate a novel method for cross-linking of AC and GO using extract solution from tubers and cereals splinters
To clarify interfacial behaviors and mechanisms of organic pollutants and RGO/AC composite
To synthesize nanoscale zero-valent iron/silver@AC/RGO and its application in trihalomethanes removal from drinking water
To explore interfacial mechanisms of trihalomethanes on the surface of the composite.

1. Application of Graphene/Activated Carbon-based Materials: Removal Characteristics and Mechanisms of Organic Pollutants in Water

2. CONTENTS 1 General introduction 2 Cross-linked activated carbon-graphene oxide composites 3 Optimization of cross-linking process 4 Nanoscale zero-valent iron / silver@activated carbon-reduced graphene oxide 5 Conclusions and recommendation s

3. General Introduction

4. Effect of organic pollutants on human’s life （ 有机污染物对人类生活的影响） Background 研究背景 A potential technology is required for efficiency remove such pollutants from water environment

5. Background 研究背景 Membrane technologies Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis Oxidation Oxidation and filtration Photochemical oxidation Photo catalytic oxidation Biological oxidation In situ oxidation Coagulation Flocculation Adsorption Activated carbon Activated alumina Iron based sorbents Zero valent iron Miscellaneous sorbents Ion exchange Organic pollutants treatment Treatment technologies used to remove organic pollutants from liquid phase ( 去除液相有机污染物的处理技术 ) Adsorption: easy and green operation, regeneration . Disadvantages :U nable to Degrade the pollutants on the surface of adsorbents

6. Activated carbon and graphene oxide Background 研究背景 Activated carbon(AC) Graphene oxide (GO) AC and GO are popular materials used adsorption process. Regardless to their advantages or drawbacks in water treatment, their combination as composite (AC/GO) promote their application in different sectors. Process is very complex Controlling GO content coated on AC Controlling the bond between AC and GO Using chemicals which are no green Thus, the simple and green technology for preparation AC/GO composite is highly required, furthermore the composite should have the degradation ability. Challenges in preparation of AC/GO composite

7. To investigate a novel method for cross-linking of AC and GO using extract solution from tubers and cereals splinters To clarify interfacial behaviors and mechanisms of organic pollutants and RGO/AC composite To synthesize nanoscale zero- valent iron/ silver@AC /RGO and its application in trihalomethanes removal from drinking water To explore interfacial mechanisms of trihalomethanes on the surface of the composite. Objectives 研究目标

8. 2. Cassava flour extracts solution to induce gelatin cross-linked activated carbon-graphene oxide composites: The adsorption performance of dyes from aqueous Media

9. GO : 0.5%, GO 1 : 0.5% GO at 350°C, GO 2 : 0.5% GO at 500°C Finding a promising way of improving the adsorption capacity of AC by linking with desired amount of GO using the extract solution from cassava flours. Experimental and Characterization AC/GO CES 90 o C AC/RGO 500 o C AC+GO

10. Results and discussion Two broad diffraction at 24 and 43 o C are assigned to diffraction from (002) and (100) crystal planes of graphite. AC present slight broadband compare to that of AC-GO. The meso -microporous are presented as key factor for adsorption process. XRD FTIR BET

11. Adsorbents S BET (m 2 g -1 ) Pore volume (cm 3 g -1 ) Pore size (nm) GAC 760.88 0.3678 1.9335 PAC 867.31 0.4212 1.95602 GAC- GO a 735.39 0.3580 1.9474 PAC- GO a 853.11 0.4198 1.9432 GAC- GO b 940.82 0.4590 1.9432 PAC- GO b 1161.67 0.5849 2.0140 Textural parameters Results and discussion

12. Results and discussion Removal efficiency increases with increasing dosage adsorbents MB completely removed within 5 min After regeneration study AC-GO showed a promising potential future application

13.   The kinetic parameters of MB and DR23 adsorption     Pseudo-first-order Pseudo-second-order Intraparticle diffusion Sorbents Sorbates q e exp (mg/g) q e cal (mg/g) K 1 R 2 q e exp (mg/g) q e cal (mg/g) K 2 R 2 C K diff R 2 PAC MB 100.00 1.41 22×10 -1 0.967 100.00 101.00 4.3×10 -2 1.000 0.35 95.0 0.973 DR23 34.73 113.29 55×10 -2 0.876 34.73 38.67 7.9×10 -3 0.998 1.80 6.30 0.980 PAC-GO MB 100.00 13.36 36×10 -1 0.970 100.00 100.00 4.2×10 -3 1.000 0.60 99.0 0.164 DR23 62.14 56.67 21×10 -2 0.976 62.14 68.73 4.5×10 -3 0.997 3.20 11.90 0.863 GAC MB 100.00 81.40 36×10 -2 0.953 100.00 103.84 8.9×10 -3 0.999 3.60 45.52 0.7784 DR23 21.41 16.98 22×10 -2 0.976 21.41 22.99 2.1×10 -2 0.998 0.97 6.30 0.780 GAC-GO MB 100.00 65.98 35×10 -2 0.991 100.00 102.60 1.4×10 -2 0.999 3.00 54.6 0.669 DR23 33.94 135.49 58×10 -2 0.735 33.94 38.46 6.9×10 -3 0.996 1.80 5.10 0.848 Results and discussion

14. Results and discussion q e increases with initial concentration, temperature enhances adsorption process and pH did not affect MB adsorption while DR23 decreased with high pH value.

15. The adsorption isotherm parameters of MB and DR23 adsorption     Langmuir isotherm Freundlich isotherm Sorbents Sorbates q m (mg/g) k L (L/mg) R 2 k F (mg/g)(L/mg) 1/n n R 2 PAC MB 193.80 27×10 -6 0.999 176.7 1.0 0.935 DR23 66.30 35×10 -3 0.997 19.8 4.0 0.987 PAC-GO MB 248.14 106×10 -8 0.999 126.70 15.0 0.701 DR23 114.81 178×10 -3 0.985 19.70 2.9 0.970 GAC MB 167.79 157×10 -4 0.995 122.63 10.90 0.935 DR23 44.33 578×10 -2 0.996 16.90 3.75 0.979 GAC-GO MB 222.72 189×10 -6 0.999 190.65 15.36 0.998 DR23 66.8 42×10 -3 0.996 16.90 3.8 0.988 *Conditions: 0.02 g of adsorbent, 0.05 mL of aqueous solution, temperature = 25 o C, pH = 6.5 Results and discussion

16. Pollutants Adsorbents q m (mg/g) References MB PAC-GO 248.14 This work GAC-GO 222.72 This work GO-AC 147.00 (Abd-Elhamid et al., 2019) Graphene 153.85 (Liu et al., 2012) Magnetic Chitozan /graphene oxide 70.03 (Shi, Li et al. 2014) Magnetic graphene oxide 64.20 (Yao et al., 2010) DR23 PAC-GO 114.81 This work GAC-GO 66.80 This work Cationized sawdust 65.80 ( Hebeish et al., 2011) Corn Stalks 27.00-52.00 ( Fathi et al., 2015) Orange peel 10.70 ( Doulati Ardejani et al., 2007) Comparison of the adsorption capacity ( q m ) for MB and DR23 by adsorbents Results and discussion

17. Conclusions A simple method based on the use of cassava powder extract solution to synthesize activated carbon-graphene was proposed The adsorption mechanisms involved electrostatic interaction, π-π interaction, and van der Vaal’s interaction.

18. 3. Optimization cross-linking of activated carbon and reduced graphene oxides by extract solution of fermented waste flours and its application for ibuprofen and bisphenol A removal from aqueous solution

19. Experimental Images of the f ermentation processes Preparation of flour and extract solution (ES) by fermentation and nonfermentation processes for both tubers and cereals Effect of ES from fermented sweet potatoes (a 1 ), nonfermented fermented sweet potatoes (a 2 ), fermented Irish potatoes (b 1 ), nonfermented Irish potatoes (b 2 ), fermented cassava (c 1 ), and nonfermented cassava (c 2 ), fermented sorghums (d 1 ), nonfermented sorghums (d 2 ), fermented wheat (e 1 ), nonfermented wheat (e 2 ), fermented maize (f 1 ), and nonfermented maize (f 2 ) on the cross-linking of AC and GO; effect of temperature (g 1 -g 3 ), acid (h), alkaline (j), and salinity (k) on the cross-linking of AC and GO ES from both fermented tuber and cereal wastes displays good cross-linking performance, especially from cassava and wheat.

20. Results and discussion SEM XRD FTIR Raman FTIR SEM , XRD, FTIR, and Raman results confirm the cross-linking of AC-GO. The targeted pollutants were adsorbed on surface of AC-GO as confirmed by FTIR results.

21. Adsorbents S BET (m 2 g –1 ) Pore volume (cm 3 g –1 ) Pore size (nm) AC 760.88 0.37 1.93 RGO/AC a 921.62 0.46 2.08 RGO/AC b 899.04 0.45 4.29 RGO/AC c 897.21 0.45 1.99 RGO/AC d 926.86 0.48 2.05 RGO/AC e 888.41 0.43 1.95 RGO/AC f 893.62 0.46 2.04 RGO/AC 1 965.80 0.48 3.41 RGO/AC 2 970.70 0.47 3.64 Textural properties of AC and RGO/AC composites a = cassava ES, b = sweet potato ES, c = Irish potato ES, d = Wheat ES, e = Sorghum ES, f = Maize ES, 1 = GO ratio of 2.3%, and 2 = GO ratio of 3.4% Results and discussion The surface increased after linking GO with AC. The surface area increase with the concentration of GO

22. Elemental composition of AC-based adsorbents Samples C wt. % H wt. % O wt. % N wt. % S wt. % AC 81.15 1.86 13.53 0.16 0.077 GO/AC 1 86.35 2.23 21.20 0.48 0.980 RGO/AC 1 79.83 2.95 9.05 0.41 0.072 GO/AC 2 87.22 2.44 16.50 0.27 0.073 RGO/AC 2 86.56 2.63 12.34 0.30 0.063 Results and discussion The number of elements increased after cross-liking. The big amount Sulfur in GO/AC 1 , generated from CES. The reduction process was confirmed by decreasing of element in RGO/AC 1,2 . C1s XPS peak is graphitic carbon , other peaks are C–O and C = O. the presence of carbon functional group promotes the hydrophilicity of RGO/AC and improve hydrogen bonding during the adsorption process.

23. Effect of adsorbent dosage on the BPA removal efficiency (a) and IBP removal efficiency (b) Results and discussion Adsorption increases with high amount of dosage and decreased with the increasing of pH.

24. Experimental conditions: adsorbent dosage: 0.4 g/L, temperature: 25 °C, pH = 7.0, and C = 50 mg/L Results and discussion The BPA and IBP are removed in a single system within a shorter time than in a binary system, likely due to the competitive effect between the molecules. The adsorption of BPA and IBP by AC/RGO is dominated by pseudo-second-order kinetics.

25. Experimental conditions: adsorbent dosage: 0.4 g/L, temperature: 25 °C, 35 °C, 45 °C, and 60 °C, pH = 7.0, C = 40 mg/L, 50 mg/L, 60 mg/L, and 80 mg/L) Results and discussion BPA adsorption is reduced as the temperature increases. This result is likely attributed to lower adsorption forces between binding active sites on the surface of AC, RGO/AC and BPA molecules . The adsorption competence of BPA on the surface of RGO/AC composites in binary system was low. The adsorption of BPA by AC/RGO is dominated by Freundlich isotherms in both single and binary systems .

26. Experimental conditions: adsorbent dosage: 0.4 g/L, temperature: 25 °C, 35 °C, 45 °C, and 60 °C, pH = 7.0, C = 40 mg/L, 50 mg/L, 60 mg/L, and 80 mg/L) Results and discussion The IBP removal efficiency for all the AC-based adsorbents decreases with increasing initial concentrations due to a constant number of adsorptive sites. The IBP adsorption capacity decreases as the temperature increases, which suggests an exothermic process. IBP adsorption by AC in a single system is better described by the Langmuir model than the Freundlich model, while better fitted to the Freundlich isotherm model for IBP adsorption by RGO/AC composites.

27. Physical regeneration conditions ( sintered at 400 °C ), chemical regeneration ( 90% ethyl ether and 10% methanol, C = 50 mg/L, and pH = 7.0) Results and discussion The BPA and IBP adsorption efficiencies obtained using a physically regenerated sample are higher than those obtained using a chemically regenerated sample. The occupied active sites, including the pores, are well recovered after pyrolyzing and decomposing adsorbed adsorbate molecules into carbon oxides and H 2 O.

28. Effect of Cl – , NO 3 – , ethanol on BPA (a, c, e) and IBP (b, d, f) removal by AC-based adsorbents from aqueous solution. ( Experimental conditions: adsorbent mass: 0.4 g/L, and temperature: 25 °C) Results and discussion The efficiency of BPA and IBP removal by the RGO/AC composites first increases and then decreases as the concentration of NaCl increases. NO 3 – favors the BPA and IBP adsorption process, implying the lack of interference between adsorbate molecules and NO 3 – on the surface of the RGO/AC composites. With increasing proportions of ethanol in the solvent, the BPA and IBP removal efficiency is apparently decreased. This outcome shows that the weakening polarity of the solvent, i.e., the weakening hydrophobic property of BPA or IBP molecules, is positively correlated with the BPA and IBP adsorption performance.

29. Conclusions The fermentation pretreatment is conducive to enhancing the cross-linkage property of these wastes A relatively high temperature, pH solution, and salinity are beneficial for good cross-linking phenomena The BPA and IBP adsorption characteristics for RGO/AC are prone to heterogeneous chemical processes that are different from those obtained using AC The electrostatic force and hydrophobic force are primary interactions for both BPA and IBP

30. 4. Synthesis of Nanoscale Zero-valent Iron / Silver@Activated Carbon-Reduced Graphene Oxide: Adsorption and Degradation of Trihalomethanes from Drinking Water

31. Preparation of AC-GO, AC-RGO, and A nZVI / Ag@AC-RGO composites *c-chemical reduction method; t-thermal reduction method Experimental The THMs molecules could not be degraded by AC The THMs removal efficiency should be enhanced .

32. SEM images (a–d), EDS analysis and mapping images (e), XRD patterns (f) and N 2 adsorption-desorption isotherm curves (g) of pristine AC, AC-RGO, nZVI@AC-RGO , and nZVI / Ag@AC-RGO composites and the XRD patterns of the treated samples. XPS survey (a), decomposed Fe2p spectrum (b), decomposed O1s spectrum (c), and Ag3d spectrum (d) of the raw nZVI / Ag @AC-RGO composite. Results and discussion

33. Adsorbents S BET (m 2 g ‒1 ) Pore volume (cm 3 g ‒1 ) Pore size (nm) AC 760.88 0.37 1.93 AC-RGOT 940.82 0.42 1.96 nZVI@AC-RGO T 776.30 0.38 1.96 nZVI/Ag@AC-RGO T 770.54 0.38 1.95 AC-RGO C 735.39 0.36 1.95 nZVI/Ag@AC-RGO C 632.31 0.59 2.01 *T-GO reduced by thermal treatment , *C-GO reduced by chemical treatment Results and discussion Textural properties of AC and RGO/AC composites

34. Experimental conditions: dosage = 0.1 g/L, t = 720 min, pH = 7.0, C = 800 μg /L, T = 25°C AC-RGO@nZVI/Ag prepared using combination of pyrolysis and liquid reduction exhibited a better performance. The optimal dosage is 0.1 g/L. Results and discussion

35. The modified composite enhanced the THMs removal efficiencies. The difference on removal efficiency of THMs between the modified and pristine AC decreased as the number of Br atoms increased. Results and discussion

36. Results and discussion The adsorption of THMs was fitted to Pseudo-second-order kinetic, and this process is prone to chemical adsorption. The adsorption of CHCl 3 and CHBrCl 2 was fitted to Elovich kinetic, furtherly demonstrating a chemical process.

37. The adsorption isotherm is fitted to Freundlich model, indicating adsorption is a heterogeneous, multilayer and chemical adsorption. Temperature brings a little influence on THMs adsorption. Anions such as NO 3 – 、 SO 4 2 – and Cl – illustrate a slight influence on THMs adsorption. Results and discussion

38. Fe Degree of iron surface oxidation deepened after adsorption of THMs due to reaction between iron and THMs molecules. Results and discussion O

39. Ag Degree of silver surface oxidation slightly changed after adsorption of THMs molecules. Apparent appearance of Cl - and Br - was observed after treatment of the composite. Results and discussion

40. Results and discussion The concentration of CHCl 3 decreases along by prolonging contact time, coinciding with the contact time effect. CHCl 3 degraded to CH 2 Cl 2 as this chemical presented in solution.

41. Results and discussion The concentration of CHBrCl 2 decreases along by prolonging contact time, coinciding with the contact time effect. CHBrCl 2 molecules are decomposed to CH 3 Cl and can be degraded into CH 2 Cl 2 .

42. Results and discussion The concentration of CHBr 2 Cl decreases along by prolonging contact time, coinciding with the contact time effect. CHBr 2 Cl, molecules are decomposed to CH 3 Cl and CH 2 Cl 2 .

43. Results and discussion The concentration of CHBr 2 Cl decreases along by prolonging contact time, coinciding with the contact time effect. CHBr 3 degraded into dibromomethane (CH 2 Br 2 ) as new peak appear at 24.629 min.

44. Results and discussion Physical factors such as surface area, pore structure etc. could determine the adsorption mechanism. The adsorption mechanisms also determined by the chemical interaction such as H-Bond, pi-interaction, hydrophobicity and degradation reaction provided by bimetallic on surface of RGO/AC

45. The removal efficiency of THMs by modified activated carbon was significantly improved, The order of adsorption capacity of modified activated carbon toward THMs was: CHBr 3 > CHBr 2 Cl > CHBrCl 2 > CHCl 3 . The adsorption of THMs by modified activated carbon is mainly heterogeneous, multilayer and chemical adsorption. As the number of Br atoms in the THMs molecule increases, the degree of surface oxidation deepens. The efficiency improvement may be related to the hydrophobicity, bond energy and other factors of THMs. The C-X (Cl, Br) bonds were decomposed into smaller molecules, Cl− and Br− by nZVI/Ag@AC-RGO composite. Conclusions

46. 5. Conclusion s and R ecommendation s

47. The green and simple method by using cassava flour extract solution to induce cross-linking between Activated carbon and graphene oxide. by this method activated carbon- reduced graphene oxide (AC-RGO) was successful synthesized and then applied in removing dyes in water solution. The optimization of synthesis of AC-GO(RGO/AC), the extract solution from fermented and nonfermented root tubers and cereals splinters waste flour was investigated to induce the cross-linking between AC and GO. The optimized RGO/AC composites presented a high efficiency in simultaneous removal BPA and IBP form aqueous solution. The AC-GO was modified by nanozerovalent iron –silver bimetallic to enhance its degradation ability of THMs from drinking water. The nZVI/Ag@AC-RGO presented the high removal efficiency compare to the pristine AC. Conclusions

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