• 한국물환경학회지
• /
• 제20권3호
• /
• pp.241-244
• /
• 2004

Radiation treatment with gamma-rays and electron-beams was used to remove polyvinyl alcohol(PVA), one of the main components of dyeing wastewater. PVA was effectively decomposed by radiation treatment, thus the removal was near 100 % at an initial PVA concentration of 44 mg/L. However, total organic carbon(TOC) removal was less than 5 % due to lower transformation of PVA to $CO_2$. This directly indicates the radiation treatment alone is not appropriate for the complete decomposition of PVA. In this sense, the improvement of biodegradability($BOD_5/COD$) of PVA by radiation treatment was studied. Both gamma-ray and electron-beam treatments significantly increased the biodegradability of PVA by transforming non-biodegradable PVA to biodegradable by-products. This suggests radiation treatment, especially electron-beam treatment that showed better improvement of biodegradability, can be used as a pre-treatment of biological degradation process of PVA.

• 유기물자원화
• /
• 제16권3호
• /
• pp.83-90
• /
• 2008

하수슬러지의 초음파 전처리시 용존성 유기물의 증가와 혐기성 생분해도 향상을 평가하였다. 하수슬러지의 초음파에 의한 가용화는 세포벽의 파괴로 인하여 용해성 화학적 산소요구량, 단백질 및 탄수화물의 농도 증가와 입자크기를 감소시켰다. 혐기성 생분해도 측면에서초음파 전처리는 메탄가스 발생량을 증가시켜 혐기성 생분해를 향상시키는 것으로 나타났다. 하수슬러지의 생화학적 메탄 잠재 발생량 실험결과 초음파 전처리 후 슬러지의 최종 메탄 수율은 294.3 ml $CH_4/gVS$로 나타나 전처리를 하지 않은 경우 211.3 ml $CH_4/gVS$에 비해 약 40 % 향상된 값을 보였다. 이와 같은 결과를 고려 시 하수슬러지의 가용화는 혐기성 생분해도 향상에 효과적인 것으로 나타났다.

• Bulletin of the Korean Chemical Society
• /
• 제35권12호
• /
• pp.3521-3526
• /
• 2014

A magnetic sonophotocatalyst $Fe_3O_4@SiO_2@TiO_2$ is synthesized for the enhanced biodegradability of organophosphate pesticide. The as-prepared catalysts were characterized using different techniques, such as X-ray diffraction (XRD) and transmission electron microscopy (TEM). The radial sonophotocatalytic activity of $Fe_3O_4@SiO_2@TiO_2$ nanocomposite was investigated, in which commercial dichlorvos (DDVP) was chosen as an object. The degradation efficiency was evaluated in terms of chemical oxygen demand (COD) and enhancement of biodegradability. The effect of different factors, such as reaction time, pH, the added amount of catalyst on $COD_{Cr}$ removal efficiency were investigated. The average $COD_{Cr}$ removal efficiency reached 63.13% after 240 min in 12 L sonophotocatalytic reactor (catalyst $0.2gL^{-1}$, pH 7.3). The synergistic effect occurs in the combined sonolysis and photocatalysis which is proved by the significant improvement in $COD_{Cr}$ removal efficiency compared with that of solo photocatalysis. Under this experimental condition, the $BOD_5/COD_{Cr}$ ratio rose from 0.131 to 0.411, showing a remarkable improvement in biodegradability. These results showed that sonophotocatalysis may be applied as pre-treatment of pesticide wastewater, and then for biological treatment. The synthesized magnetic nanocomposite had good photocatalytic performance and stability, as when it was used for the fifth time, the $COD_{Cr}$ removal efficiency was still about 62.38%.

• 유기물자원화
• /
• 제17권3호
• /
• pp.82-90
• /
• 2009

본 연구에서는 기계식 전처리에 의한 하수 슬러지의 가용화 효과를 회분식 실험을 통해 조사하였다. 기계식 전처리를 통한 하수슬러지의 가용화는 세포벽의 파괴로 통해 용존성 화학적 산소요구량, 단백질 및 탄수화물의 농도를 증가시키는 것으로 나타났다. 알칼리와 기계식 전처리를 병행하여 슬러지를 가용화한 결과 기계식 전처리만을 수행한 경우에 비해 용존성 화학적 산소요구량이 높은 것으로 나타났다. 혐기성 생분해도 측면에서 기계식 전처리는 메탄 발생량을 증가시키는 것으로 나타났다. 기계식과 알칼리 및 기계식 전처리를 동시에 수행한 경우 각각 24.1%와 44.5%의 생화학적 메탄 잠재능을 향상시키는 것으로 나타나 하수슬러지의 가용화는 혐기성 생분해도 향상에 효과적이다.

• Journal of Microbiology and Biotechnology
• /
• 제11권2호
• /
• pp.193-198
• /
• 2001

Preparation of antibacterial biopolymer film which is suitable for food packaging film was investigated using K-carrageenan as a base material. K-Carrageenan showed good biodegradability and film-forming characteristic but poor mechanical properties under humid condition. Also, various bacteria grew well on its surface. The poor mechanical properties could be improved by mixing with alginate at a 1:1 ratio and crosslinking with $CaCl_2$ solution. Antibacterial property coul be provided by modifying the K-carrageenan film surface with acrylic acid plasma followed by ion-exchange with $Ag^+$ ions. Such prepared film still showed good biodegradability by various fongi.

• Environmental Engineering Research
• /
• 제16권2호
• /
• pp.103-109
• /
• 2011

This work experimentally determined the effect of thermal and microwave pretreatments on the anaerobic digestion of mixtures of municipal primary and secondary sludges in semi-continuous mesophilic digesters at hydraulic retention times (HRT) of 20, 15, 10, 7, and 5 days. The ratio of soluble chemical oxygen demand (COD) to total COD in thermally pretreated and microwaved sludges at $80^{\circ}C$ was 2.7 and 3.2 times higher than that of raw sludge, respectively. The volatile solids (VS) and COD removal efficiencies in all three digesters fed with raw (control), thermally pretreated (TM), and microwaved (MW) sludges decreased as the HRT was reduced. The highest relative improvement in VS removal compared to the control occurred at the HRT of 5 days in the TM and MW (29 and 41% higher than the control, respectively). At this HRT, improvement in the COD removal efficiencies in the TM and MW compared to the control was 28 and 53%, respectively. Improvements in biogas production compared with the control increased in both the TM and MW as the HRT was reduced to 5 days. The relative improvement in daily biogas production compared to the control from the TM and MW was 33 and 53% higher than the control at the HRT of 5 days, respectively. The results show that microwave pretreatment is more effective than thermal pretreatment in increasing the solubilization degree and mesophilic anaerobic biodegradability of sewage sludge.

• 한국축산시설환경학회지
• /
• 제17권3호
• /
• pp.197-204
• /
• 2011

돈 분뇨 슬러리를 대상으로 하여 기계적 분쇄와 캐비테이션 그리고 오존을 적용하여 원료의 특성 변화와 생분해도 그리고 메탄 생성잠재성 변화를 측정한 시험결과를 요약한 주요 내용은 다음과 같다. 1. 분쇄방법과 캐비테이션의 방법의 경우 큰 입자 및 미세입자를 줄일 수 있는 효과가 있었다. 2. 오존처리의 방법의 경우 용존물질의 부분산화, 미세입자의 부분산화 및 가용화 촉진을 통해 혐기성 소화의 첫 단계인 가수분해를 더욱 촉진할 것으로 사료된다. 3. 입도분포 변화에 따른 메탄생성량의 변화는 분쇄처리할 경우가 캐비테이션과 오존 처리방법에 비해 더 양호한 메탄생성효율을 보였다.

• Environmental Engineering Research
• /
• 제24권4호
• /
• pp.662-669
• /
• 2019

Anaerobic digestion is a popular sewage sludge (Ss) treatment method as it provides significant pollution control and energy recovery. However, the low C/N ratio and poor biodegradability of Ss necessitate pretreatment methods that improve solubilization under anaerobic conditions in addition to anaerobic co-digestion with other substrates to improve the process efficiency. In this study, three pretreatment methods, namely microwave irradiation, ultrasonication, and heat treatment, were investigated, and the corresponding improvement in methane production was assessed. Additionally, the simplex centroid design method was utilized to determine the optimum mixture ratio of food waste (Fw), livestock manure (Lm), and Ss for maximum methane yield. Microwave irradiation at 700 W for 6 min yielded the highest biodegradability (62.0%), solubilization efficiency (59.7%), and methane production (329 mL/g VS). The optimum mixture ratio following pretreatment was 61.3% pretreated Ss, 28.6% Fw, and 10.1% Lm. The optimum mixture ratio without pretreatment was 33.6% un-pretreated Ss, 46.0% Fw, and 20.4% Lm. These results indicate that the choice of pretreatment method plays an important role in efficient anaerobic digestion and can be applied in operational plants to enhance methane production. Co-digestion of Ss with Fw and Lm was also beneficial.

• Biomaterials and Biomechanics in Bioengineering
• /
• 제5권1호
• /
• pp.65-86
• /
• 2020

As conventional drug delivery system is being improved rapidly by target-based drug delivery system, finding suitable Drug Delivery System (DDS) for new drugs remains a challenge. Although there are many drug delivery vehicles in existence, a significant improvement is required to some DDS such as for local, implant-based treatments used for musculoskeletal infections. Many polymers have been considered for providing the improvement in DDS. Synthetic polymer, for example, has gained popularity for broad-spectrum physicochemical and mechanical properties. This article reviews the biomedical applications of Poly(TriMethylene Carbonate-co-Caprolactone) (PTMCC), which has attracted attention due to its biocompatibility, biodegradability and rubber-like properties. Its synthesis, physical properties, and degradation are also discussed here. Although it is relatively new in biomedical applications, it is readily usable for the fabrication of differing format of DDS of superior mechanical strength and degradation properties. The use of PTMCC is expected to increase in coming years as more is revealed about its potentials.

• Macromolecular Research
• /
• 제15권1호
• /
• pp.44-50
• /
• 2007

This study investigated the effect of ultrasound irradiation on the blend of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). The blends of PLA/PBAT(50/50) (PBAT50) were prepared in a melt mixer with an ultrasonic device attached. Thermal, rheological, and mechanical properties, morphology, and biodegradability of the sonicated blends were analysed. The viscosity of the sonicated blends was increased by the ultrasound irradiation owing to the strong interaction. The morphology of the sonicated blends was significantly dependent on the duration o the ultrasound irradiation. For PBAT50, the phase size reduction was maximized when the blends were ultrasonically irradiated for 30 sec. At longer duration of ultrasound irradiation, the PBAT phase underwent flocculation. Measurement of the tensile properties showed an increased breakage tensile stress and an enhanced Young's modulus when the blends were properly irradiated. This improvement was ascribed to better adhesion between the PLA matrix and the PBAT domain and to better dispersion of the PBAT phase. However, the tensile properties were maximized after excessive energy irradiation, which was ascribed to an emulsifying effect leading to coalescence of the PBAT phase. Impact strength was increased to reach a peak with the ultrasound irradiation, and was higher than the untreated sample for all sonicated samples due to the difference of failure mechanism between the tensile test and the impact test.