In this work, we report a direct preparation of a few-walled carbon nanotube (FWCNTs) and NiMgAl composites namely FWCNT-NiMgAl by pyrolysis of waste high-density polyethylene (HDPE) plastic at 800 °C with NiMgAl-layered double hydroxide (LDH) as catalysts. The composite formation is carried out in a single step using our lab-developed pyrolysis reactor. The NiMgAl-LDH catalyst was prepared by co-precipitation method and the FWCNTs were grown on the NiMgAl-LDH catalyst with FWCNT yield of 10% and FWCNT-NiMgAl composite yield of 55% whose quality is determined by Raman ID/IG ratio of 2.57. The average outer and inner diameter of the FWCNT are found to be 5.5 nm and 2.9 nm, respectively, from TEM and 2.92 nm from the outer RBM (radial breathing mode) band, which indicates the formation of a few-walled CNTs. FWCNT-NiMgAl is used for the fabrication of flexible supercapacitor electrodes on a polyethylene terephthalate (PET) sheet which achieved a specific capacitance of 432 Fg− 1 in a wide potential range (ΔV = 2) at a scan rate of 5 mV s− 1 in 2 M KOH electrolyte with a high energy density of 240 Wh kg− 1, whereas NiMgAl displayed a capacitance of 200 Fg− 1 with an energy density of 111 Wh kg− 1. The diffusion-type charge storage mechanism (pseudocapacitance) is found to be dominant with contributions of 73.2% and 69.75% for NiMgAl and FWCNT-NiMgAl, respectively. The highest specific capacitance and energy density are obtained for NiMgAl in 2 M KCl and for FWCNT-NiMgAl in 2 M NaOH electrolytes. However, the largest potential window is observed in KOH electrolyte for both NiMgAl and FWCNT-NiMgAl with value of ΔV = 2 V. The electrode material shows good stability in acidic electrolytes and also shows good capacitive stability at high frequencies maintaining a phase angle of 70°. The present work is a novel approach to fabricate low-cost multifunctional carbon composite nanomaterials and will contribute to the research on low-cost waste-derived CNT composite preparation and its application in flexible energy storage devices.

The plastic strategy adopted by the EU in January 2018 was established to implement circular economic policies and the Sustainable Development Goals(SDGs) of the United Nations. The strategy includes the vision and implementation measures to achieve, which are primarily measures to improve recycling and increase demand for recycled plastics. The representative measures include the design that considers recycling possibilities, reinforcement of demand for recycled plastics, suppression of occurrence, and response to micro-plastics. The policies to implement these measures include legislative restrictions and economic measures (EPR, GPP). It is especially desirable that the policies are applied differently depending on the plastic product. The Korean government has established comprehensive measures for all stages from production to recycling, but those measures are not comprehensive compared to the EU’s strategy. The reason is that the refusal of waste collection makes the Korean government establish the approach from the aspect of waste management instead of the implementation of a circular economy or SDGs like the EU. The countermeasures are aimed at achieving a 50% reduction in waste generation amount and a 70% recycling rate. It is considered that the possibility of achieving the goal will increase by examining the measures and policy means in the EU’s plastics strategy.

In this study, the amount of plastic waste produced in Korea and the state of its treatment are analyzed. In addition, trends in sales prices of recyclable resources are identified and used as basic research data in countermeasures for the rejection of recyclable waste collection companies. According to the state of waste generation and disposal nationwide in 2017, the amount of plastic waste generated increased by 7.2% annually over the five-year period starting in 2012, reaching 7.1 million tons in 2016. In the case of composition ratio, 36.7% of household wastes occupy. In the case of the plastic recycling market, the demand for recycled waste plastics and plastics decreased due to sluggish domestic and overseas economies since 2015, and the prices of synthetic resins such as PE, PP, and PS of pellets dropped by about 20%. As for the selling prices of recyclable resources in apartment houses in March 2017, the average selling price including plastics is 1071 won/ month·generation. When plastic was excluded it was 941 won/month·generation, which amounts to about a 130 won/month·generation difference. The average selling price of recyclable resources over the period of March- May 2018 is about 697 won/month·generation. In March 2017, it was found to decrease by about 26% of the sale price.

지구 부존자원의 채굴량 한계, 산업규모의 증가 등으로 인해 수요에 비해 공급량 부족 현상이 발생할 것으로 예상됨에 따라 이미 사용수명이 다한 폐기물로부터 유효한 자원을 다시 회수하는 재활용 이슈가 부각되고 있다. 특히, 근대화된 도시로부터 발생하는 폐기물은 기하급수적으로 증가하고 있으며, 이 중 자동차와 더불어 전자제품은 주요 ‘도시광산’으로써 중요성이 점점 증가하고 있다. 우리나라는 지난해(2016년) 약 25만 톤의 폐전자제품(냉장고, 세탁기, TV, 에어컨, 휴대폰 등)을 회수하였으며, 정책 및 제도의 개선으로 해마다 회수율은 증가하고 있는 실정이다. 이들 폐전자제품에서 모터, 고철, 비철금속 등은 재사용 및 재활용되고 있지만, 대부분의 합성수지는 압축 처리되어 매립 및 소각되고 있다. 고체 산업폐기물은 소각하여 감용화하고 매립하는 것이 일반적이다. 그러나 폐플라스틱의 소각과 매립은 경제적인 손실뿐만 아니라 환경오염의 거시적인 원인이 되고 있다. 폐플라스틱의 소각에 의한 처리는 일부 열에너지를 이용할 수 있지만 많은 경제적인 손실을 초래하고, 염화수소에 의한 소각로의 부식과 다이옥신 등 각종 유독성 가스를 방출하여 환경문제를 유발할 수 있다. 또한 플라스틱의 매립은 매립 부지의 확보문제뿐만 아니라 유해성분이 용출될 수 있으며, 단위 무게에 비해 부피가 커 매립효율을 저하시키고, 물리･화학적으로 안정되어 있는 난분해성이라 매립지의 조기 안정화와 흙 속에 반영구적으로 잔존하는 문제가 발생한다. 그리고 분해 시 토양오염 및 유해가스를 대기 중에 발생하는 등 여러 가지 문제를 야기 시킨다. 따라서 플라스틱 산업 및 환경보호를 위해서는 재활용 기술개발이 시급히 이루어져야 할 것이다. 본 연구에서는 전자제품의 재활용율 향상을 위해 전자제품에서 발생하는 폐플라스틱을 대상으로 재질분리 연구를 수행하였다. 비중선별 및 정전선별 연구를 수행하였으며, 다양한 조건 변화를 통해 최적 분리조건 및 분리효율을 규명하여 대상 시료의 분리 가능성을 확인하였다.

우리나와 같이 삼면이 바다인 지역은 연안 해역에서의 대규모 어업활동 및 산업화로 인하여 해상 및 해저의 침적 폐기물, 패각류, 퇴적 오염물 등 해양폐기물 발생량의 증가로 인하여 인류의 정화조라 표현되던 해양은 오염이 날로 심각한 상태에 이르고 있다. 본 연구는 해변에 밀려온 해안폐기물을 대상으로 고형연료 활용 가능성 및 활용 보관, 이동성을 확보하기 위한 펠렛 성형 조건을 분석하였다. 해안폐기물은 그물류, 목재류 등 높은 가연성 물질로 고에너지 고형연료 가능성이 높다. 이를 압축성형을 통한 펠렛 고형연료 생산을 위한 강도별 성형 특성을 분석하였으며, 특히, Polyethylene계 해안폐기물은 펠렛 성형, 형태의 유지 등의 평가를 통해 성형 가능성이 높은 반면 Nylon계 해안폐기물은 성형 형태 유지의 어려움이 있다고 판단된다. 해안폐기물이 고형연료 성형시, Polyethylene는 성형바인더 역할을 수행하여, 압축강도는 350 kg/cm² 이상에서 성형 및 형태 유지가 용이한 조건을 나타냈다. 이렇게 생산된 해안폐기물 고형연료는 높은 Carbon 함량 및 휘발분 함량 등으로 저위발열량은 7,000 kcal/kg이상을 나타냈다.

In this study those currently operating SRF (Solid Refuse Fuel) combustion plant were selected for the investigation. The SRF component analysis, and the reaction time to collect contaminants collected and analyzed. As the result, the average caloric value of the SRF was about 8,114 kcal/kg and the result of the analysis was satisfied with the Fuel standard. The SRF could be used as an alternative Coal fuel. However CO, NOx and Dust analysis result was exceeded the emission standard. In case of Hydrogen chloride, high concentration of emission from the facilities was observed. Although normal operation was performed, ineffective the operational management causedt, incomplete blockage of drug injection facilities and personnel management system. To prevent such problems, a regular maintenance of facilities is need to be installed. At the moment applied to the monitoring system (TMS) are installed in waste incinerators with the medium to large capacities, However such as a periodically monitoring system is needed to manage a small solid fuel boliers as well.

There are many stringent environmental regulations on the management of waste electrical and electronic equipments(WEEE) in most developed countries. WEEE directive aims at increasing collection and recycling rate of WEEE whereas,while the restriction of the use of certain hazardous substances (RoHS) aims at restricting hazardous materials duringthe production of electrical and electronic equipment (EEE). TV housing rear covers consist of small portion of brominatedflame retardants (BFRs). Improper management and disposal of such waste can pose impacts on the environment andhuman health. In Korea, there are very few available statistical data regarding BFRs levels in TVs housing rear covers.In order to provide additional measures related to management of BFRs, there is a need for a quantitative material flowstudy on the amount of BFR found in TVs. This can be achieved by the aid of material flow analysis of the TV setsand by studying the Deca-BDE components present in the TV housing read covers. In this study, the relevant data werecollected from the statistical reports and through field site visits to the WEEE recycling facilities with surveys. Staticand dynamic material flow analysis (MFA) was conducted to determine material flow of BFRs (Deca-BDE) in themanagement of waste TVs. According to this study, in 2011, households in Korea use 73,821ton of TV sets of which23,592ton of waste TV sets were collected and recycled by municipalities and producers. Extended ProducerResponsibility (EPR) played a major role in recycling of WEEE. In this study, it was predicted that Deca-BDE in usestage would reach down to 51.73ton by 2016. In addition, the amount of Deca-BDE present at the disposal and recyclingstage is estimated to be approximately 2.45ton by 2018.