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- 저자 : Daniel C. W. Tsang (검색결과 74 건)
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Stefaniuk, Magdalena,Tsang, Daniel C.W.,Ok, Yong Sik,Oleszczuk, Patryk Elsevier 2018 Journal of hazardous materials Vol.349 No.-
<P><B>Abstract</B></P> <P>The bioavailable PAHs (freely dissolved concentration, Cfree) were determined in sewage sludge (SL) or sewage sludge and biochar (BC) amended soil. SL or SL with a 2.5, 5 or 10% of BC was applied to the soil. The study was conducted as a long-term field experiment. Addition of BC to SL at a dose of 2.5 and 5% did not affect the content of Cfree PAHs in soils. However a significant difference (by 13%) in Cfree PAHs content was noted in experiment with 10% addition of BC. During the experiment, the concentration of Cfree PAHs in SL- and SL/BC-amended soil decreased. In particular sampling terms the content of Cfree PAHs in SL/BC-amended soil was significantly lower comparing to the Cfree PAHs content in SL-amended soil. After 18 months, Cfree PAH content was significantly lower in SL/BC-amended soil than in the experiment with SL alone, and did not differ significantly from the Σ16 Cfree content in the control soil. The largest decrease relative to the soil with sewage sludge alone was observed for 3-, 5- and 6-ring PAHs. This is the first field-based evidence that biochar soil amendment was effective to reduce of the Cfree of PAHs in sewage sludge-amended soils.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Freely dissolved (C<SUB>free</SUB>) PAHs was evaluated in sewage sludge-biochar-amended soil. </LI> <LI> Application of sewage sludge alone increased C<SUB>free</SUB> PAHs content in soil. </LI> <LI> Biochar added with sewage sludge contributed to a decrease in the C<SUB>free</SUB> PAHs. </LI> <LI> Reduction of C<SUB>free</SUB> PAHs depended on biochar contribution in sewage sludge. </LI> </UL> </P>
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Vellingiri, Kowsalya,Tsang, Daniel C.W.,Kim, Ki-Hyun,Deep, Akash,Dutta, Tanushree,Boukhvalov, Danil W. Elsevier 2018 Journal of Cleaner Production Vol.199 No.-
<P><B>Abstract</B></P> <P>In the treatment of spent wastes, seeking extra economic incentives (e.g., through their regeneration into value-added end products) along with environmental protection is a highly ideal option to consider. In this context, a process was developed to utilize spent alkaline battery waste as a source medium of zinc (Zn<SUP>2+</SUP>) ions for the synthesis of a high-value material, metal organic frameworks (MOFs). For this purpose, multiple options including acid leaching and base precipitation were first compared for separation of Zn<SUP>2+</SUP> ions from battery waste. Secondly, MOF-5 synthesis was carried out through two different routes: one using the Zn<SUP>2+</SUP> ions separated from waste batteries (W-MOF-5) and the other using pure chemicals (P-MOF-5). Finally, differences in the structural properties (e.g., crystallinity and morphology) between the two MOF-5 types were assessed through characterization experiments (e.g., FTIR, PXRD, and SEM analyses) and modeling (DFT) studies. W-MOF-5 was found to possess tetragonal lattice parameters which indicated decrease in the Zn<SUP>2+</SUP> ions in the framework. This deficiency increased the interplanar Bragg angles which led to the different size and shape of W-MOF-5. Also, the PXRD spectrum indicated the presence of all peaks at similar position with that of P-MOF-5. Additionally, the preparation of 1 kg of W-MOF-5 requires a low cost (42 USD) when one considers >90% of solvent recovery. Also in terms of materials cost, the synthesis of W-MOF-5 was highly cost-effective than that of ZnO nanoparticles. In light of many compatibilities between MOFs synthesized through the two different routes, the method proposed in this work can be further developed toward a simple, fast, and reliable route for MOF-5 production from battery waste.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Shen, Zhengtao,Fan, Xiaoliang,Hou, Deyi,Jin, Fei,O'Connor, David,Tsang, Daniel C.W.,Ok, Yong Sik,Alessi, Daniel S. Pergamon Press 2019 Chemosphere Vol. No.
<P><B>Abstract</B></P> <P>Based on the “waste-treat-waste” concept, biochars were produced from cadmium (Cd)-contaminated rice straw (CRSBs) at 300, 500, and 700 °C (CRSB300, CRSB500, and CRSB700). The risks of the Cd remaining in CRSBs were evaluated and the optimal biochar pyrolysis temperature for Cd removal was investigated. It was observed that 41% of the total Cd in the raw rice straw was exchangeable, which may pose significant risks to crops and humans. Pyrolyzing at 300 °C did not significantly alter the Cd fractions, while the exchangeable fraction of Cd greatly dropped to 5.79% at 500 °C and further to 2.12% at 700 °C. Increasing the highest pyrolysis temperature resulted in CRSBs with higher pH values, greater surface area, and smaller pore sizes, thus providing more rapid and efficient removal of Cd from aqueous solutions. For Cd removal tests, increasing pyrolysis temperature (300–700 °C) increased the total (24.8–55.1 mg/g) and non-exchangeable (18.9–52.8 mg/g) Cd concentrations immobilized on the CRSBs and significantly decreased the exchangeable Cd fraction (23.7%–4.85%). It is suggested based on the study from aqueous solutions that CRSB700 was the most suitable for the remediation of Cd contaminated soil on site due to the lowest risks of remained Cd from feedstock, fastest and highest Cd removal, and most stable immobilization of Cd.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 41% of Cd in raw rice straw was exchangeable, posing great environmental risks. </LI> <LI> Pyrolyzing at 300 °C did not significantly alter Cd fractions remained in biochar. </LI> <LI> Exchangeable fraction of Cd dropped to 5.79% at 500 °C and to 2.12% at 700 °C. </LI> <LI> Increasing temperature decreased exchangeable Cd fraction immobilized on biochar. </LI> <LI> CRSB700 has the fastest and highest Cd removal, and most stable Cd immobilization. </LI> </UL> </P>
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Sulfonated biochar as acid catalyst for sugar hydrolysis and dehydration
Xiong, Xinni,Yu, Iris K.M.,Chen, Season S.,Tsang, Daniel C.W.,Cao, Leichang,Song, Hocheol,Kwon, Eilhann E.,Ok, Yong Sik,Zhang, Shicheng,Poon, Chi Sun Elsevier 2018 CATALYSIS TODAY - Vol.314 No.-
<P><B>Abstract</B></P> <P>This study investigated the use of 30 w/v% H<SUB>2</SUB>SO<SUB>4</SUB> sulfonated wood waste-derived biochar as catalysts for production of value-added chemicals from carbohydrates in water as an environmentally benign solvent. Physicochemical characteristics of the sulfonated biochar were revealed by Fourier transform infrared spectroscopy (FTIR), acid-base neutralization titration, gas adsorption analysis, thermogravimetric analysis (TGA), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Using the sulfonated biochar as catalysts, hydrolysis of maltose at 140–160 °C resulted in the maximum glucose yield of 85.4% and selectivity of 88.2%, whereas dehydration of fructose at 160–180 °C produced the maximum HMF yield of 42.3% and selectivity of 60.4%. A higher range of reaction temperature was required for fructose dehydration due to the higher energy barrier compared to maltose hydrolysis. While increasing the temperature accelerated the catalytic reactions, the maximum product selectivity remained unchanged in the sulfonated biochar-catalyzed systems. The products were stable despite the increase in reaction time, because rehydration and adsorption of products was found to be minor although polymerization of intermediates led to unavoidable carbon loss. This study highlights the efficacy of engineered biochars in biorefinery as an emerging application.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochar catalyst sulfonated by 30% w/v H<SUB>2</SUB>SO<SUB>4</SUB> achieved 42.3% yield and 58.7% selectivity HMF from fructose. </LI> <LI> Maltose hydrolysis to glucose with yield and selectivity of 85.4% and 88.2% was achieved at lower temperatures. </LI> <LI> Higher temperature accelerated the conversion but did not change the maximum yield and selectivity. </LI> <LI> Energy barrier of dehydration is larger than hydrolysis and requires higher temperature or stronger acidity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Igalavithana, Avanthi Deshani,Yang, Xiao,Zahra, Hilda Rizkia,Tack, Filip M.G.,Tsang, Daniel C.W.,Kwon, Eilhann E.,Ok, Yong Sik Elsevier 2018 Science of the Total Environment Vol.630 No.-
<P><B>Abstract</B></P> <P>Previous studies indicated that using CO<SUB>2</SUB> as a reaction agent in the pyrolysis of biomass led to an enhanced generation of syngas <I>via</I> direct reaction between volatile organic carbons (VOCs) evolved from the thermal degradation of biomass and CO<SUB>2</SUB>. In addition, the physico-chemical properties of biochar in CO<SUB>2</SUB> were modified. In this current study, biochars generated from red pepper stalks in N<SUB>2</SUB> and CO<SUB>2</SUB> (RPS-N and RPS-C, respectively) were tested for their effects on the immobilization of Pb, Cd, Zn, and As in contaminated soils. Soils were incubated for one month with 2.5% of RPS, and two biochars (<I>i.e.</I>, RPS-N and RPS-C) at 25°C. After the incubation period soils were analyzed to determine the amendment effects on the behavior of metal(loid)s. The potential availability and mobility kinetics of metal(loid)s were assessed by single extraction of ammonium acetate and consecutive extraction of calcium chloride, respectively. Sequential extraction was used to further examine potential changes in geochemical fractions of metal(loid)s. The increased soil pH induced by application of the biochars reduced the potentially available Pb, Cd, and Zn, while RPS-C significantly reduced Pb due to the high surface area and aromaticity of RPS-C. However, RPS-C mobilized potentially available As compared to RPS-N due to the increased soil pH. Biochars reduced the mobility kinetics of Pb, Cd, and Zn, and RPS-N effectuated the greatest reduction of As mobility. The RPS-C increased the Fe and Mn oxides, hydroxide, and organically bound Pb, while both biochars and RPS-N increased residual Cd and Zn, and organically bound As, respectively. When considering the two biochars, RPS-C was highly effective for immobilization of Pb in soils, but it had no effect on Cd and Zn and a negative effect on As. In addition, RPS-C significantly increased the total exchangeable cations in soils.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochars markedly reduced Cd, Pb and Zn mobility in soils. </LI> <LI> Biochar pyrolyzed in CO<SUB>2</SUB> most effectively immobilized Pb. </LI> <LI> Biochar pyrolyzed in CO<SUB>2</SUB> increases As mobility more. </LI> <LI> More siloxane groups present in biochar pyrolysed in CO<SUB>2</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Kim, Hye-Bin,Kim, Seon-Hee,Jeon, Eun-Ki,Kim, Do-Hyung,Tsang, Daniel C.W.,Alessi, Daniel S.,Kwon, Eilhann E.,Baek, Kitae Elsevier 2018 The Science of the total environment Vol.636 No.-
<P><B>Abstract</B></P> <P>To date, studies on the mobility of arsenic (As) in soil amended with biochar have primarily relied on broad empirical observations, resulting in a gap between the behavior of As in amended soil and the chemical mechanisms controlling that behavior. This study focuses on the influence of abiotic factors in As mobility in As-contaminated soils amended with biochar. In order to understand the leaching of DOC and phosphate across a range of biomass feedstock and pyrolysis temperature, rice straw and granular sludge from an anaerobic digester were pyrolyzed at 300, 550, and 700 °C, and subjected to leaching studies by mixing air dried soil with 10 wt% of biochar at a soil: water ratio of 1:1(w/v). The concentration of DOC in the presence of granular sludge biochar and rice straw biochar increased from 190 mg L<SUP>−1</SUP> to 2605 mg L<SUP>−1</SUP> and 1192 mg L<SUP>−1</SUP>, respectively, which considerable accelerated the mobilization of Fe and As. More specifically, DOC drove the reduction of Fe(III) to Fe(II). Our results suggest enhanced release of As via the reductive dissolution of iron oxides, including by the chelating-enhanced dissolution of Fe oxides, and competitive desorption by DOC and phosphate from biochar. The influence of DOC and phosphate was further evaluated using realistic application amounts (1, 3, and 5 wt%) of biochars derived from pyrolysis of granular sludge, rice straw and spent coffee ground at 300 and 550 °C. The results from these experiments further confirm that DOC is a key factor for influencing the mobility of As in the amendment of biochar to As-contaminated soil, which indicates that biochar having low levels of leachable carbon should be amended to As-contaminated soils, and with caution.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dissolved organic carbon from biochar increased mobility of As in soil. </LI> <LI> Biochar enhanced reductive dissolution of Fe oxides in soil. </LI> <LI> Dissolved organic carbons extract Fe via chelating enhanced dissolution. </LI> <LI> Phosphate enhanced As mobility via competitive desorption </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Biodiesel synthesis using chicken manure biochar and waste cooking oil
Jung, Jong-Min,Lee, Sang-Ryong,Lee, Jechan,Lee, Taewoo,Tsang, Daniel C.W.,Kwon, Eilhann E. Elsevier Applied Science 2017 Bioresource technology Vol.244 No.1
<P><B>Abstract</B></P> <P>This study laid an emphasis on the possible employment of biochar generated from pyrolysis of chicken manure to establish a green platform for producing biodiesel. To this end, the pseudo-catalytic transesterification reaction using chicken manure biochar and waste cooking oil was investigated. Compared with a commercial porous material (SiO<SUB>2</SUB>), chicken manure biochar generated from 350°C showed better performance, resulting in 95.6% of the FAME yield at 350°C. The Ca species in chicken manure biochar imparted strong catalytic capability by providing the basicity for transesterification. The identified catalytic effect also led to the thermal cracking of unsaturated FAMEs, which decreased the overall FAME yield. For example, 40–60% of converted FAMEs were thermally degraded. To avoid undesirable thermal cracking arising from the high content of the Ca species in chicken manure biochar, the fabrication of chicken manure biochar at temperatures ≥350°C was highly recommended.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biodiesel synthesis using chicken manure biochar. </LI> <LI> Establish a green platform for producing biodiesel using chicken manure biochar. </LI> <LI> Enhanced yield of biodiesel using chicken manure biochar due to strong catalytic capability. </LI> <LI> 95.6% of the FAME yield using chicken manure biochar generated from 350°C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Chen, Season S.,Wang, Lei,Yu, Iris K.M.,Tsang, Daniel C.W.,Hunt, Andrew J.,Jé,rô,me, Franç,ois,Zhang, Shicheng,Ok, Yong Sik,Poon, Chi Sun Elsevier 2018 Bioresource technology Vol.247 No.-
<P><B>Abstract</B></P> <P>This study aims to produce levulinic acid (LA) from paper towel waste in environment-friendly and economically feasible conditions, and evaluate the difference using solid and aqueous Brønsted acids. Direct dehydration of glucose to LA required sufficiently strong Brønsted acidity, where Amberlyst 36 demonstrated rapid production of approximately 30Cmol% of LA in 20min. However, the maximum yield of LA was limited by mass transfer. In contrast, the yield of LA gradually increased to over 40Cmol% in 1M H<SUB>2</SUB>SO<SUB>4</SUB> at 150°C in 60min. The SEM images revealed the conversion in dilute acids under microwave at 150°C resulting in swelling structures of cellulose, which were similar to the pre-treatment process with concentrated acids. Further increase in reaction temperature to 200°C significantly shortened the reaction time from 60 to 2.5min, which saved the energy cost as revealed in preliminary cost analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 30% of levulinic acid (LA) yielded from paper towel over Amberlyst 36 in 20min. </LI> <LI> Maximum yield of LA was comparable using dilute sulphuric acid at 150 and 200°C. </LI> <LI> Cellulose underwent swelling in dilute acid with microwave heating at 150°C. </LI> <LI> Conversion at 200°C shortened reaction time and reduced total energy consumption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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