luận văn chromium vi removal from aqueous solution by using silver nano activated carbon

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY HA THI LAN ANH CHROMIUM (VI) REMOVAL FROM AQUEOUS SOLUTION BY USING SILVER NANO-ACTIVATED CARBON BACHELOR THESIS Study Mode: Full-time Major: Environmental Science and Management Faculty: Advanced Education Program Office Batch: 2014 - 2018 Thai Nguyen, 25/09/2018 h Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Environmental Science and Management Student name Ha Thi Lan Anh Student ID DTN 1454290001 Thesis title Chromium (VI) removal from aqueous solution by using Silver nano-activated carbon Supervisor(s) Dr Van Huu Tap (Faculty of Environment and Earth Science, Thai Nguyen University of Sciences) Abstract: Chromium (Cr(VI)) is a heavy metal that can cause a serious impact on the environment and human – being The treatment of Cr(VI) was reported through several methods such as chemical precipitation, adsorption, membrane filtration, coagulation/flocculation, ion exchange and absorption However, absorption is considered one of the most idea method for Cr(VI) removal Activated carbon is a low-cost material derived from wood or other organic waste from the shell and coir As the main constituent of coal is carbon, so all the carbon-rich fuels can be used to make activated carbon Besides, silver nano particles as a catalyst for modifying activated carbon to increase the adsorption capacity of activated carbon In this study, the activated carbon loaded silver nanoparticle (AgNPs-AC) was used as a low-cost adsorbent to remove Cr (VI) from the aqueous solution Batch absorption i h experiments were conducted to evaluate the effects of pH, initial concentrations of Cr(VI), contact time and dose of AgNPs-AC on Cr(VI) removal efficiency The results showed that at pH = 4, contact time of 180 min, 20mg AgNPs-AC/25mL of K2Cr2O7 solution with initial Cr(VI) concentration at mg/L were the most suitable conditions for adsorption of Cr VI) from aqueous solutions The optimum adsorption capacity achieved after processing was 27.70mg/g at 20 mg/25mL of AgNPs-AC dose and 40 mg/L initial Cr(VI) The adsorption kinetic data were found to fit well with the pseudo-first and second order models with very high correlation coefficients From this study, it can be concluded that AgNPs-AC is an interesting adsorbent, saving, easy to remove Cr (VI) from the aqueous solution Keywords Silver nano-activated carbon, Chromium, Adsorption capacity, Activated carbon Number of pages: 40 Date of submission: 25/09/2018 ii h ACKNOWLEDGEMENT First of all, I would like to thank you teachers at University of Agriculture and Forestry – University of Thai Nguyen has dedicated teaching me during the period of study at the school I would like to express deep gratitude to the teachers Dr Van Huu Tap whose guidance, encouragement, suggestion and very constructive criticism have contributed immensely to the evolution of my ideas during the project Without his guidance, I may not have this report At the same time, I also want to express my deep gratitude to Dr Vu Xuan Hoa, who gave me a chance to interact with a nanotechnology field I also thank faculty of Environment and Earth Science – Thai Nguyen University of Sciences - Thai Nguyen University has facilitated me throughout the course of the thesis Finally yet important, I took this opportunity to express my deepest appreciation to my families, relatives, friends who encouraged and supported me unceasingly and all who directly or indirectly, have lent their helping hand in this venture Thank you all very much! Thai Nguyen, 25/09/2018 Student Ha Thi Lan Anh iii h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon TABLE OF CONTENTS ACKNOWLEDGEMENT iii TABLE OF CONTENTS iv LIST OF FIGURES vi LIST OF TABLES vii PART I INTRODUCTION 1.1 Research rationale 1.2 Research's objectives: .2 1.3 Research hypotheses: 1.4 Limitations 1.5 Definitions………………………………………………………………………………………….3 PART II LITERATURE REVIEW 2.1 Chromium 2.1.1 Electronic and molecular structure of hexavalent chromium compounds .4 2.1.2 Sources of Chromium .5 2.2 Routes of exposure (Chromium) .5 2.2.1 Air 2.2.2 Drinking-water .6 2.2.3 Food 2.3 Coconut shell activated carbon 2.4 Silver nanoparticles 2.5 Silver nano-activated carbon (AgNPs-AC) .8 PART III METHOD .9 luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon iv h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon 3.1 Materials 3.1.1 Chemicals .9 3.1.2 Adsorbent materials 3.1.3 Laboratory instruments 10 3.2 Location and research time 11 3.3 Research Contents 11 3.4 Adsorption experiments of Chromium (Cr6+) onto (AgNPs –AC) 11 3.4.1 Measurements .15 3.4.2 Data analysis 15 PART IV RESULTS AND DISSCUSSION 16 4.1 Characterization of the nano-activated carbon 16 4.2 Effect of impregnation ratio (AgNPs/AC) on Cr(VI) adsorption capacity .18 4.3 Effect of pH .20 4.4 Effect of contact time 21 4.5 Effect of adsorbent dose 23 4.6 Effect of initial Cr(VI) concentrations 24 4.7 Adsorption isotherm 25 4.8 Adsorption kinetics of AgNPs-AC 31 PART V CONCLUSION .35 REFERENCES 36 luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon v h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon LIST OF FIGURES Figure 4.1 SEM image of (a) AC and (b) AgNPs-loaded activated carbon (AgNPsAC), EDS spectra of (c) AC and (d) AgNPs-loaded activated carbon (AgNPs-AC) 17 Figure 4.2 XRD graph of (a) activated carbon from coconut shells (AC) and (b) AgNPs 2% - loaded activated carbon (AgNPs-AC) 18 Figure 4.3 The effect of the impregnation ratio on chromium adsorption at concentration of 10 mg/L, adsorbent dose: 10 mg AgNPs-AC/25mL Cr6+ solution, Contact time=60 and Temp: 250C 19 Figure 4.4 Effect of pH on the removal of Chromium ion [Cr]=10mg/L, Contact time=60 min, adsorption dose=10mg/25mL, Temp (25C±20C) 21 Figure 4.5 Effect of Contact Time on the Removal of Chromium ion [Cr]=10 mg/L; adsorbent dose=10mg/25mL; pH=4;Temp (25C±20C) 22 Figure 4.6 Effect of adsorbent dose on the removal of Chromium ion [Cr] =10mg/L: Contact time=180 min: pH=4: Temp (25±2oC) 24 Figure 4.8 Adsorption isothermal equilibrium prediction of Cr(VI) onto AgNPs-AC at contact time = 180 min, Ag-AC dose = 20 mg/25mL, initial pH: 4, Temp: 250C) 30 Figure 4.9 Kinetics model of Cr(VI) adsorption onto AgNPs-AC (Co: 10mg/L; adsorbent dosage: 20 mg/25 mL, initial pH: 4, Temp: 250C) 33 luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon vi h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon LIST OF TABLES Table 1: Levels of daily chromium intake by humans from different routes of exposure Table 2: Adsorption isothermal parameters and correlation coefficients of Langmuir, Freundlich and Temkin models for sucrose adsorption on Chromium 31 Table 3: Calculated kinetic parameters of models for adsorption of Chromium onto AgNPs-AC .34 luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon vii h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon PART I INTRODUCTION 1.1 Research rationale Chromium, named for its multicolored compounds, is a transition metal, number 24 in the periodic table of elements This element is found in combination, mainly in chromite ores, and, even if in lower abundant amounts, as crocoites (PbCrO4) and chrome ochre (Cr2O3) Cr is a major element that exists primarily in two different oxidation states, hexavalent and trivalent These oxidation states are denoted as Cr(VI) and Cr(III), respectively The rarely found naturally occurring element has zero oxidation, Cr(0), other oxidation states of Cr are not stable and therefore, are not found in the natural environment Cr(VI) is more flexible than Cr(III) and dificult to remove in water (Elisabeth L Hawley et al, 2004) This chromium (VI) detoxification leads to increased levels of chromium (III) (ATSDR, 1998) Air emissions of chromium are predominantly of trivalent chromium, and in the form of small particles or aerosols (ATSDR, 1998) and (SAIC.PM, 1998) The most important industrial sources of chromium in the atmosphere are those related to ferrochrome production Ore refining, chemical and refractory processing, cementproducing plants, automobile brake lining and catalytic converters for automobiles, leather tanneries, and chrome pigments also contribute to the atmospheric burden of chromium (U.S Environmental Protection Agency, 1998) The general population is exposed to chromium (generally chromium [III]) by eating food, drinking water and inhaling air that contains the chemical The average daily intake from air, water, and food is estimated to be less than 0.2 to 0.4 micrograms (µg), 2.0 µg, and 60 µg, luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon h luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon respectively (ATSDR, 1998) Dermal exposure to chromium may occur during the use of consumer products that contain chromium, such as wood treated with copper dichromate or leather tanned with chromic sulfate (ATSDR, 1998) Occupational exposure to chromium occurs from chromate production, stainless-steel production, chromium plating, and working in tanning industries; occupational exposure can be two orders of magnitude higher than exposure to the general population (ATSDR, 1998) People who live in the vicinity of chromium waste disposal sites or chromium manufacturing and processing plants have a greater probability of elevated chromium exposure than the general population Several technologies have been applied to remove Cr(VI) from aqueous solutions including precipitation, reverse osmosis, ion exchange, filtration, sand filtration, chemical reduction/oxidation, electrochemical precipitation, membrane filtration, solvent extraction, and electrochemical deposition and adsorption (ChiChuan-Kan, 2017) Adsorption is an effective and low cost method Particularly, the problem of chromium pollution in water resources is causing concern in major cities and industrial parks; therefore, it is necessary to have a method to remove Cr from the water environment In this study, Cr was treated by adsorption with the adsorbed material is activated carbon coconut shell 1.2 Research's objectives The purpose of this study was to load silver nanoparticles into activated carbon deriving from coconut shell and application for removing chromium from aqueous solution Research on finding the appropriate impregnated rate, evaluation of appropriate conditions for adsorption, including: pH, sorption time, adsorbent dosages luan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbonluan.van.chromium.vi.removal.from.aqueous.solution.by.using.silver.nano.activated.carbon h