• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.57-68
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• 2023

In this study, coffee waste was recycled into nitrogen-doped porous carbon fibers as an active material for high-energy EDLC (Electric Double Layer Capacitors). The coffee waste was mixed with polyvinylpyrrolidone and dissolved into dimethylformamide. The mixture was then electrospun to fabricate coffee waste-derived nanofibers (Bare-CWNF), and carbonization process was followed under a nitrogen atmosphere at 900℃. Similar to Bare-CWNF, the as-synthesized carbonized coffee waste-derived nanofibers (Carbonized-CWNF) maintained its fibrous form while preserving the composition of nitrogen. The electrochemical performance was analyzed for carbonized coffee waste (Carbonized-CW)-, carbonized PAN-derived nanofibers (Carbonized-PNF)-, and Carbonized-CWNF-based electrodes in the operating voltage window of -1.0-0.0V, Among the electrodes, Carbonized-CWNF-based electrodes exhibited the highest specific capacitance of 123.8F g^-1 at 1A g^-1 owing to presence of nitrogen and porous structure. As a result, nitrogen-contained porous carbon fibers synthesized from coffee waste showed excellent electrochemical performance as electrodes for high-energy EDLC. The experimental designed in this study successfully demonstrated the recycling of the coffee waste, one of the plant-based biomass that causes the environmental pollution into high-energy materials, also, attaining the ecofriendliness.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.509-515
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• 1998

Activated coffee chars were prepared from coffee waste by chemical activation with zinc chloride. In this study, the following processes were carried out ; roasting step, carbonization step, chemical activation step, and washing and drying step. The roasting step of coffee waste was carried out at $300{\sim}400^{\circ}C$ for 10 minutes. The optimum condition of carbonization was at $650^{\circ}C$ for 1 hour. The most important parameter in chemical activation of coffee char was found to be the chemical ratio of activation agents. Activated coffee chars prepared by various activation methods were characterized in terms of the nitrogen BET surface area, the BJH pore volume and pore size distribution at 77 K. The $N_2$-BET surface areas and total pore volume of coffee chars prepared by the chemical activation with $ZnCl_2$ were determined as about $1110{\sim}1580m^2/g$ and $0.51{\sim}0.81cm^3/g$, respectively. Scanning Electron Microscopy (SEM) was used to observe the porosity and surface of activated coffee chars. From the results of SEM analysis, it was shown that active surface and many pores were formed after the chemical activation. The preparation of the activated coffee char from coffee waste was successfully carried out, which previews a possibility for exploitation of resources by recycling the waste.

• The Korean Journal of Food And Nutrition
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• v.12 no.6
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• pp.602-607
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• 1999

과일 및 한약재 폐기물을 이용하여 중금속 제거력을 조사하기 위하여 Cd, Pb 용액에서 사과껍질 모과 밤내피(밤 친껍질) 인삼, 키위껍질, 대추, 원두커피가루의 입자별, 농도별, 온도별 흡착정도를 조사한 결과는 다음과 같다 입자의 크기가 작아질수록 사과껍질을 제외한 모든폐기물에 있어서 중금속 흡착력은 증가되었고 중금속별 제거량은 Cd는 인삼폐기물이 3,506-4.659mg/g Pb은 밤 친 껍질이 9.189-9.582mg/g으로 다른 과일 및 한약재 폐기물보다 높았다 농도별 중금속 흡착력은 중금속의 농도가 높을수록 증가하였는데 Cd은 인삼 폐기물이 1,929-3.800mg/g. Pb은 밤 친 껍질이 0.930-9.3685mg/g으로 다른 과일 및 한약재 폐기물보다 높았다. 온도별 중금속 흡착량은 온도가 높아질수록 증가하여 껍질이 9.368-9.613mg/g으로 다른 과일 및 한약재 폐기물보다 증가하였다. 이상의 결과로부터 물에 함유된 중금속을 제거하는데 과일 및 한약재 폐기물을 이용할 수 있을것으로 생각된다.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.2
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• pp.44-49
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• 2014

In order to remove the heavy metals from synthetic wastewater containing Pb, Cr, and Cd, the experiment was conducted with a variety of concentration and pH by using the washed and dried coffee grounds as adsorbent. Almost of the heavy metals were removed in thirty minutes and the removal efficiency was maximized to the 80 percents following the different pH conditions. Furthermore, in the case of Cr, the removal efficiency was declined with the increasing of pH. As a result of this study, coffee grounds is proved to be a very good adsorbent to remove the heavy metals.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.185-194
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• 2022

Coffee is one of the most consumed beverages in the world and is the second largest traded commodity after petroleum. Due to the great demand of this product, large amounts of waste is generated in the coffee industry, which are toxic and represent serious environmental problems. This study aims to study the possibility of recycling spent coffee grounds (SCG) as a mineral admixture by replacing the cement in the manufacturing of concrete. To recycle the coffee g rounds, the SCG was dried to remove moisture and fired in a kiln at 850 ℃ for 8 hours. Carbonized coffee grounds are produced as coffee grounds ash (CGA) through ball mill grinding. The chemical composition of the prepared coffee grounds ash was investigated using X-ray fluorescence (XFR). According to the chemical composition analysis, the major elements of coffee grounds ash are K₂O(51.74 %), CaO(15.92 %), P₂O₅(14.39 %), MgO(7.74 %) and SO₃(6.89 %), with small amounts of F₂O₃(0.66 %), SiO₂(0.59 %) and Al₂O₃(0.31 %) content. To evaluate quality and mechanical properties, substitutions of 5, 10, and 15 wt.% of coffee grounds ash (CGA) were tested. From the quality test results, the 28-day activity index of CGA5 reached 80 %, and the flow value ratio reached 96 %, which is comparable to the minimum requirement for second-grade FA. From the test results of the mortar, the optimal results have been found in specimens with 5 wt-% coffee grounds ash, showing good mechanical and physical properties.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.48-59
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• 2018

This study was conducted to suggest the effective management and recycling processes of coffee waste, which can be easily obtained from coffee shops and coffee-related products industries. Prior to the fabrication of pellets, the potential of coffee waste as a raw material of pellet was investigated through the examination of its chemical compositions and fuel characteristics. Major gradient included in coffee waste was holocellulose, followed by fat/oil and protein. Coffee waste contained a small quantity of ash (0.7%), such as calcium, sodium, potassium and magnesium. Interestingly, coffee waste was easily dried probably due to its porous structure. Pellets fabricated with coffee waste and larch sawdust showed good fuel characteristics, such as moisture content, ash content, density and durability. The pellets exceed greatly the minimum requirements of $1^{st}$-grade wood pellet standard designated by National Institute of Forest Science (NIFOS). Particularly, the high calorific value of coffee waste showed the potential as a raw material of pellet. However, owing to high nitrogen and sulfur contents, coffee waste is like to be used as a raw material of wood pellet for combined heat and power plants equipped with a reduction system of $NO_x$ and $SO_x$ gases. On the other hand, 91 wt% larch sawdust and 9 wt% coffee waste are required to fabricate the $1^{st}$-grade wood pellets designated by NIFOS. Pellets fabricated with the conditions are estimated to have nitrogen content of 0.298% and sulfur content of 0.03%. Lastly, if amounts of coffee waste and sawdust in the production of wood pellets are adequately adjusted according to its purchasing price, the manufacturing cost of pellet can effectively be reduced. In addition, it is expected tp prepare the effective recycling process of waste and to relieve the environmental burden with the reduction of waste from the commercialization of coffee waste/larch pellets.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.426-433
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• 2023

Capacitor performance was considered using coffee grounds-based activated carbon produced through oil extraction and KOH activation to increase the utilization of boiwaste. Oil extraction from coffee grounds was performed by solvent extraction using n-Hexane and isopropyl alcohol solvents. The AC_CG-Hexane/IPA produced by KOH activation after oil extraction increased the specific surface area by up to 16% and the average pore size by up to 2.54 nm compared to AC_CG produced only by KOH activation without oil extraction. In addition, the pyrrolic/pyridinic N functional group of the prepared activated carbon increased with the extraction of oil from coffee grounds. In the cyclic voltage-current method measurement experiment, the specific capacitance of AC_CG-Hexane/IPA at a voltage scanning speed of 10 mV/s is 133 F/g, which is 33% improved compared to the amorphous capacity of AC_CG (100 F/g). The results show improved electrochemical properties by improving the size and specific surface area of the mesopores of activated carbon by removing components from coffee grounds oil and synergistic effects by increasing electrical conductivity with pyrrolic/pyridinic N functional groups. In this study, the recycling method and application of coffee grounds, a bio-waste, is presented, and it is considered to be one of the efficient methods that can be utilized as an electrode material for high-performance supercapacitors.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.544-549
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• 2017

The spent coffee grounds (SCG) are considered valuable by-products because they contain various bioactive compounds. The SCG extraction (SCGE) was irradiated at doses ranging between 30 and 50 kGy. The deep dark-brown color of SCGE was changed to a bright yellow color by gamma irradiation. The content of the bioactive compounds of gamma-irradiated SCGE was analyzed by high-performance liquid chromatography. Interestingly, the content of quinic acid was increased by gamma irradiation, whereas other compounds were decreased. Although the contents of bioactive compounds were changed by gamma irradiation, the biological activities (radical scavenging activity and whitening effects) of SCGE were unaffected. Our findings suggest that gamma irradiation can effectively improve the color values of SCGE without the loss of biological activities. Consequently, gamma irradiation can be a useful tool for improving the utilization of SCGE in the cosmetic industry.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.15-21
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• 2016

This experiment was conducted to test desorption and recycling characteristics for silver ion adsorbed into waste coffee grounds by using various desorbing agents such as nitric acid, ethylene diamine triacetic acid (EDTA) and nitrilo triacetic acid (NTA). It is appeared that the highest desorption efficiency for silver ions was obtained as about 97.8 % by 1.0 M of nitric acid solution. Also, in the case of less than 1.0 of the ratio of solid and liquid (S/L) (g/L), silver ions adsorbed onto coffee grounds was desorbed as about 98~100 %, and most of desorption process was completed within 60min. In addition, adsorption capacity of reused waste coffee grounds for silver ions was highly maintained as about 43.9 mg/g until the $2^{nd}$ cycle, as compared with the adsorption capacity with 45.9 mg/g of the adsorption capacity for virgin waste coffee grounds.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.212-216
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• 1993

Agricultural and forest wastes were tested as substrate for the production of Flammulina velutipes. Among the meranti, pine tree, mixed sawdust, coffee waste and peanut hull tested, coffee waste was the best basal substrate for the production of basidiocarps. When various supplements, such as ricebran, brewer's grain, defatted corn flour, defatted soybean flour and defatted rapeseed flour were tested, defatted corn flour was chosen for the production of basidiocarps. Maximum yield of basidiocarps(129.38 g/bottle) was obtained from the mixed medium at 4 : 1 ratio of coffee waste and defatted corn flour.