The disposal of organic pollutants is one of the important research topics. Some of the studies in this field are based on the degradation of organic pollutants with a catalytic agent. The cobalt tetraoxide/peroxymonosulfate system is an important catalytic system used for the radical degradation of organic pollutants. To increase the catalytic efficiency of such reactions, graphitization of activated carbon used as a support solid and nitrogen doping to the carbon structure are commonly used methods. In this study, cobalt tetraoxide production, N-doping and graphitization were carried out in a single step by heat treatment of activated carbon doped with the phthlocyanine cobalt (II) complex. The catalytic performance of the catalyst/ peroxymonosulfate system was investigated by changing the pH, catalyst, and PMS concentration parameters on rhodamine B and 1,3,5 trichlorophenol, which were used as models. It was seen that the catalysts had 97% activity on rhodamine B in 16 min and 100% on 1,3,5 trichlorophenol in 6 min. It was observed that the catalysts continued to show high catalytic activity for five cycles in reusability studies and had a very low cobalt leaching rate. These results are in good agreement with previously published studies. In line with these results, the synthesized N-doped graphitic carbon/Co3O4 catalyst can be used as an effective catalyst for wastewater treatments.

In this study, a bipolar visible light responsive photocatalytic fuel cell (PFC) was constructed by loading a Z-scheme g-C3N4/ carbon black/BiOBr and a Ti3C2/ MoS2 Schottky heterojunction on the carbon brush to prepare the photoanode and photocathode, respectively. It greatly improved the electron transfer and achieved efficient degradation of organic pollutants such as antibiotics and dyes simultaneously in two chambers of the PFC system. The Z-scheme g-C3N4/carbon black/BiOBr formed by adding highly conductive carbon black to g-C3N4/BiOBr not only effectively separates the photogenerated carriers, but also simultaneously retains the high reduction of the conduction band of g-C3N4 and the high oxidation of the valence band of BiOBr, improving the photocatalytic performance. The exceptional performance of Ti3C2/ MoS2 Schottky heterojunction originated from the superior electrical conductivity of Ti3C2 MXene, which facilitated the separation of photogenerated electron–hole pairs. Meanwhile, the synergistic effect of the two photoelectrodes further improved the photocatalytic performance of the PFC system, with degradation rates of 90.9% and 99.9% for 50 mg L− 1 tetracycline hydrochloride (TCH) and 50 mg L− 1 rhodamine-B (RhB), respectively, within 180 min. In addition, it was found that the PFC also exhibited excellent pollutant degradation rates under dark conditions (79.7%, TCH and 97.9%, RhB). This novel pollutant degradation system is expected to provide a new idea for efficient degradation of multiple pollutant simultaneously even in the dark.

Polymeric carbon nitride (p-C3N4) is a promising platform as a metal-free photo-catalyst for various reactions. The p-C3N4 can be produced by thermal poly-condensation of organic precursors. Their morphological and chemical structures depend on reaction conditions during the poly-condensation. In this study, two p-C3N4 materials are produced by heat treatment of urea under different gaseous conditions with air (urea-derived carbon nitride under air, UCN-A) and N2 (UCN-N), respectively. UCN-A and UCN-N samples are mesoporous materials and show excellent photocatalytic activities for degrading rhodamine B, an organic pollutant, under the irradiation of visible light. The UCN-A shows the better photocatalytic activity than UCN-N. Various characterizations reveal that more porous structures and larger surface areas of UCN-A are reasons for the better photocatalytic performance.

Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of CODMn, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

Activated carbon was prepared from pre-carbonized petroleum coke. Textural properties were determined from studies of the adsorption of nitrogen at 77 K and the surface chemistry was obtained using the Fourier-transform infrared spectrometer technique and the Boehm titration process. The adsorption of three aromatic compounds, namely phenol (P), p-nitrophenol (PNP) and benzoic acid (BA) onto APC in aqueous solution was studied in a batch system with respect to contact time, pH, initial concentration of solutes and temperature. Active carbon APC obtained was found to possess a high surface area and a predominantly microporous structure; it also had an acidic surface character. The experimental data fitted the pseudo-second-order kinetic model well; also, the intraparticle diffusion was the only controlling process in determining the adsorption of the three pollutants investigated. The adsorption data fit well with the Langmuir and Freundlich models. The uptake of the three pollutants was found to be strongly dependent on the pH value and the temperature of the solution. Most of the experiments were conducted at pH 7; the pH(PZC) of the active carbon under study was 5.0; the surface of the active carbon was negatively charged. The thermodynamic parameters evaluated for APC revealed that the adsorption of P was spontaneous and exothermic in nature, while PNP and BA showed no-spontaneity of the adsorption process and that process was endothermic in nature.

The treatment of piggery wastes was carried out at pilot scale using a multilayered metal-activated carbon system followed by carbon bed filtration. The physicochemical properties were obtained from treated samples with aqueous solutions containing metallic ions such as Ag+, Cu2+, Na+, K+ and Mn2+, which main obsevations are subjected to inspect surface properties, color removal properties by Uv/Vis and EDX. Multilayered metal-activated carbons were contacted with waste water to investigation of the simultaneous catalytic effect for the COD, BOD, T-N and T-P removal. The removal results for the piggery waste using multilayered metal-activated carbon bed was achieved the satisfactory removal performance under permitted values of Ministry of Environment of Korea. The high efficiency of the multilayered metal-activated carbon bed was determined by the performance of this material for trapping, catalytic effect and adsorption of organic solid particles.

Graphene oxide (GO)-titania composites have emerged as an attractive heterogeneous photocatalyst that can enhance the photocatalytic activity of TiO2 nanoparticles owing to their potential interaction of electronic and adsorption natures. Accordingly, TiO2-GO mixtures were synthesized in this study using a simple chemical mixing process, and their heterogeneous photocatalytic activities were investigated to determine the degradation of airborne organic pollutants (benzene, ethyl benzene, and o-xylene (BEX)) under different operational conditions. The Fourier transform infrared spectroscopy results demonstrated the presence of GO for the TiO2-GO composites. The average efficiencies of the TiO2-GO mixtures for the decomposition of each component of BEX determined during the 3-h photocatalytic processes were 26%, 92%, and 96%, respectively, whereas the average efficiencies of the unmodified TiO2 powder were 3%, 8%, and 10%, respectively. Furthermore, the degradation efficiency of the unmodified TiO2 powder for all target compounds decreased during the 3-h photocatalytic processes, suggesting a potential deactivation even during such a short time period. Two operational conditions (air flow entering into the air-cleaning devices and the indoor pollution levels) were found to be important factors for the photocatalytic decomposition of BEX molecules. Taken together, these results show that a TiO2-GO mixture can be applied effectively for the purification of airborne organic pollutants when the operating conditions are optimized.

가스성 오염물질의 지표를 제공하는 이산화탄소를 시료로 사용하여, 식물의 공기정화 능력을 분석한 실험 결과는 다음과 같다. 공시 6가지 식물 모두 광합성이 활발한 낮 시간 동안에는 식물이 오염원을 흡수함에 따라, 이산화탄소 농도가 빠르게 감소하였다. 호흡작용을 통해 이산화탄소가 방출되므로 빛이 차단되는 밤 시간에는 농도가 다시 증가하였고, 특히 18시 ~ 20시 사이에는 급격한 농도 증가율을 보였다. 다음 날 아침 빛을 쬐기 시작하면 다시 오염원이 흡수되면서 농도가 감소한다. 이러한 이산화탄소 농도의 교환 현상을 통해, 빛의 양이 증가함에 따라 식물의 광합성량이 증가하며 그 결과 이산화탄소 제거율 역시 증가함을 알 수 있었다. 24시간 동안 측정한 식물별 광합성량과 호흡량을 가감한, 식물별 이산화탄소의 정화총량은 엽면적 1000 cm2 당 Ficus benjamina 49 ppm, Epipremnum aureum 99 ppm, Chamaedorea elegans 34 ppm, Fatsia japonica 123 ppm, Spthiphyllum spp. 115 ppm, Hedera helix 42 ppm으로 나타났다. 이산화탄소 순간소모량의 최대치를 보인 시간대는 각 식물별로 상이한데, 대개의 경우 광량 0.67 ~ 1.54 mW/cm3의 조건에서 가장 활발한 이산화탄소 흡수율을 보였다. Epipremnum aureum의 경우, 이산화탄소의 흡수가 비교적 높은 속도로 장기간 지속되었으며, 다른 식물에 비해 상대적으로 낮은 호흡량을 보였다. Fatsia japonica는 매우 대칭적인 이산화탄소 농도변화곡선을 보여, 광합성과 호흡이 일정하게 일어남을 알 수 있었다. 광량의 변화에 그리 민감하지 않아 폭넓은 광량조건의 실내공간에도 적합하다고 판단된다. Spthiphyllum spp. 역시 장기간에 걸쳐 비교적 안정적으로 광합성이 일어났다. Hedera helix는 1.24 mW/cm3이상의 광조건에서 상당히 높은 이산화탄소 흡수율을 보였으나, 1.00 mW/cm3이하에서의 낮은 제거율로 보아 저광도 실내공간보다는 고광도의 전이공간이나 실외에 적합하다고 판단된다. 위의 연구결과를 통하여 이산화탄소 제거에는 Fatsia japonica, Spthiphyllum spp., Epipremnum aureum 순서로 효과적임을 알 수 있었다.