상세정보

친환경적이고 저비용의 특성을 갖는 바이오차 (biochar)는 메틸렌 블루 흡착제로써 많은 연구가 진행되고 있습니다. 그러나 바이오차는 흡착제로 이용 후 회수의 문제가 있으며, 이는 2차 오염의 높은 발생 가능성과 낮은 재사용 효율을 야기합니다. 본 연구에서는 바이오차를 칼슘 알지네이트와 멜라민 스펀지를 이용하여 복합형 흡착제로 (BAMS) 제작하였습니다. 흡착능을 고려하여, 볏짚을 300 ℃에서 열분해한 바이오차가 다양한 열분해 온도 (300-800 ℃)에서 생성된 바이오차 중 복합형 흡착제의 원료로 적합하였습니다. 최적의 바이오차/소듐 알지네이트의 무게 비는 수용액 내에서 바이오차의 효과적인 포획과 메틸렌 블루 제거율을 평가하여 1:1로 선정하였습니다. 298-313 K에서 BAMS의 흡착 모델은 Pseudo-second order model과 Langmuir isotherm model에 적합하였습니다. BAMS의 8회 재사용 효율은 82.09 %로써, 기존에 보고된 바이오차 보다 높은 재사용 효율을 보였습니다. 따라서 BAMS는 산업 폐수 응용 분야의 바이오차 활용에 큰잠재력을 가지고 있었습니다. 

Biochar, an inexpensive and eco-friendly material, has been broadly studied to remove various contaminants from wastewater. However, it causes secondary environmental pollution and low reuse efficiency due to recovery challenges after the adsorption process. In this study, biochar was immobilized on a melamine sponge supported by a calcium alginate matrix to make BAMS. Considering the adsorption capacity, biochar which was produced from rice straw at 300 ℃ was determined to be the suitable adsorbent among various biochars (300-800 ℃). Optimum ratio of biochar/sodium alginate for entrapment of biochar was determined as 1:1 (w/w) by evaluating the methylene blue removal rate. Adsorption process was expressed through the Langmuir isotherm and Pseudo-second-order models. The reuse efficiency of BAMS was significantly enhanced (82.09 %) after 8 cycles compared to biochar in the previous studies. Therefore, it has a great potential for biochar application in wastewater treatment.

Contents

Abstract	………………………………………………………………...i
국문요약	…………………………………………………………….....ⅱ
Contents	………………………………………………………………ⅳ
List of Figures	………………………………………..……………….ⅵ
List of Tables	……………………………………………………….ⅸ


1. Introduction	………………………………………………………...1

2. Materials and methods	…………………………………………….5
2.1. Materials	………………………………………………………...6
2.2. Preparations of biochar from rice straw…..	…………………….6
2.3. Preparation of Biochar-Alginate composite based on Melamine Sponge (BAMS)………………………………………………………..7
2.4. Characterization….……………………………………..…….....8
2.5. Adsorption experiment…………..……………………………...8
2.6. Regeneration test……….…………………………………….....9

3. Results and discussion	…………………………………………….12
3.1. Optimization of manufacturing conditions for BAMS…………13
 3.1.1 FT-IR analysis and Elemental analysis of biochar produced from rice straw………..……………………………………………….13
 3.1.2 Adsorption of biochar based on rice straw…………………..15
 3.1.3 The determination of the optimum BAMS ratio (biochar-sodium alginate) for entrapment of biochar	…………………………..20 
3.2. Methylene blue adsorption of optimized BAMS……………….26
3.2.1 Analyis of the adsorbent characteristics	………………….....26
3.2.2 Effect of BAMS dose and initial solution pH on adsorption	………...................................................................................................30
3.2.3 Effect of the contact time on adsorption: Kinetic studies…….34
3.2.4 Effect of initial concentration of methylene blue on adsorption: Isotherm studies……………………………………………………….42
3.2.5 Thermodynamic study of BAMS……………………………45
3.2.6 Reuse efficiency test of BAMS……………………………...50

4. Conclusions	………………………………………………………..57

References	……………………………………………………………59