Activated Carbon Content Research Articles

Synergistic Effects of Irrigation and Nitrogen Fertilisation on Maize Photosynthetic Performance and Yield of Rainfed Systems in Drought‐Prone Environments

ABSTRACTMaize, a cereal crop of global significance, encounters cultivation challenges in the subtropical regions of Guangxi, mainly due to variable rainfall and low soil fertility, exacerbating the effects of drought. This study evaluated the effects of irrigation and nitrogen fertilisation on overcoming these challenges and improving maize growth and yield. Between 2020 and 2021, a split‐plot experiment was conducted. The main plots were assigned to two irrigation treatments: irrigated and rainfed. Within each main plot, subplots were treated with different nitrogen levels (0, 150, 200, 250 and 300 kg ha−1). The results showed that nitrogen levels and water regime significantly impacted several key factors, including the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci), photosynthetically active radiation (PAR), carbon‐metabolising enzymes and total carbon (TC) content accumulation. Under drought‐like rainfed conditions, the application of nitrogen, RN300 (rainfed application nitrogen 300 kg ha−1), IN250 (irrigated application nitrogen 250 kg ha−1) significantly enhanced the Pn (10.0%), Tr (3.17%), Ci (3.41%) and Gs (2.6%). Additionally, PAR was significantly influenced by the water regime and nitrogen levels. Under IN250, the capture ratio (Ca) increased (2.36%), while the penetration ratio (Pe) and reflectance ratio (Re) decreased by 13.12% and 46.36%, respectively, compared to RN300. The levels of carbon metabolism enzymes (sucrose phosphate synthase and phosphoenolpyruvate carboxylase) and the TC content were higher under RN300 compared to IN250; however, these differences were not statistically significant. Path analysis revealed that thousand kernel weight had the most significant impact on yield under both water regimes. The effect was stronger under irrigated conditions, with a path coefficient of 0.647, compared to 0.459 under rainfed conditions. Correlation analysis indicated that plant height (0.938), stem diameter (0.906), ear diameter (0.928) and ear length (0.803) were positively correlated with nitrogen levels. In conclusion, maize under IN250 exhibited superior photosynthetic performance and carbon accumulation. This suggests that balanced irrigation and nitrogen management can effectively mitigate the adverse impacts of drought on maize, optimising growth and yield sustainably.

Biological Characterization of Geo-Referenced Soil Samples from Major Rice-Growing Tracts of Southern Kerala

A survey was conducted from January to March 2023 to assess the soil biological fertility index across five agro-ecological units in the rice-growing belts of Southern Kerala. These units included Onattukara sandy loam (AEU 3), Kari soil (AEU 4), Pokkali soil (AEU 5), Southern laterites (AEU 8), and Midland laterites (AEU 9). The study was carried out in the College of Agriculture, Vellayani Thiruvananthapuram. The survey aimed to assess microbial activity and organic carbon content, thereby enhancing our understanding of the biological fertility across these diverse soil types. Twenty geo-referenced surface soil samples @ 0- 15 cm were collected in every AEU by prescribed method. The collected samples were subjected to the characterization of soil biological properties such as dehydrogenase activity, organic carbon, microbial biomass C, microbial biomass N and soil respiratory rate following the standard protocol. The findings showed that organic carbon in AEU 5 with the highest mean value (3.03 %), followed by AEU 4 (2.19 %), AEU 9 (2.01 %), AEU 8 (1.01 %), and AEU 3 (0.56 %). Dehydrogenase activity was highest in AEU 5 (682.54 µg TPF g-1 hr-1), followed by AEU 4, AEU 9, and AEU 8, and lowest in AEU 3 (76.71 µg TPF g-1 hr-1). AEU 5 exhibited the highest microbial biomass carbon and microbial biomass nitrogen activities, while AEU 8 showed the lowest. Soil respiration was highest in AEU 5 and lowest in AEU 3. Based on these soil microbiological indicators, soils were classified into three categories: low, medium, and high fertility. The Biological Fertility Index (BFI) scores indicated favorable conditions in AEU 4 and 5, moderate in AEU 9, and low in AEU 3 and 8. By establishing a comprehensive understanding of soil biological fertility across various agro-ecological units, the research aims to contribute to improved soil health and crop productivity in the region.

Highly-efficient recovery of silver from industrial cyanide-based plating effluent on TiO2/activated carbon composites

The release of silver-containing wastewater is an economic loss. In this works, the silver ions in the cyanide-based plating effluent of jewelry effluent was systematic recovered by the photocatalytic process using commercial semiconductors (TiO2, ZnO, Bi2O3 and WO3) and activated carbon (AC) enhanced semiconductors as the photocatalysts. The preliminary results demonstrated that the highest photocatalytic silver recovery was achieved via the use of TiO2 nanoparticles (NPs), ascribing to its better textural property that provided abundant active sites to undergo the reaction. The intrinsic property and activity of TiO2 were significantly improved in the presence of proper content of AC. Approximately 94% of silver was recovered within 45 min through the TiO2/AC with 14.9 wt.% AC (TiO2/AC1) under the UV-vis irradiation due to the act of AC as the conductive pathway for electron migration from CB of TiO2 along its surface, thus prolonging the lifetime of electron-hole pairs. Although a marked decrease in photocatalytic activity of the best composite was detected after the 4th use (∼50%), it exhibited an outstanding antibacterial ability compared with TiO2 and fresh one in dark environment. The work offers the avenue to design the photocatalyst for recovering the precious metals from industrial effluent and broaden the application of such recovered metal decorated photocatalyst for practical use.

Adsorption Capacity and Efficiency of Composite Thin Sheet Made of Chitosan-Activated Carbon on The Adsorption of Methylene Blue

Abstract Methylene blue (MB) is a waste dye produced by textile industries. One way to reduce MB in polluting the environment is using MB adsorbent materials, such as chitosan (CS)-based composites. This research aims to investigate the adsorption capacity and efficiency of chitosan-activated carbon composites (CS-AC), which are in the form of thin sheets, on MB adsorption. The composite was made by manually mixing the chitosan and activated carbon, and then the mixture was poured into a dish and dried at around 50 °C until a dry, thin sheet was formed. The composites were prepared with varying activated carbon mass concentrations (25%, 50%, 75%, and 100% of chitosan mass). The MB adsorption measurements were carried out using UV-Vis spectroscopy. Adsorption capacity and adsorption efficiency increase with increasing activated carbon content, and the composite containing activated carbon mass 100% of chitosan mass shows the highest values, namely 11.51 mg/g and 95.93%, respectively. Furthermore, the values of adsorption capacity and adsorption efficiency are also influenced by the initial MB concentration and mass of the adsorbent. The adsorption capacity increases with increasing initial MB concentration but decreases with increasing adsorbent mass. Adsorption efficiency increases with increasing initial MB concentration and adsorbent mass.

Cation selectivity during flow electrode capacitive deionization

Efficient separation of specific ions from aqueous media is crucial for advanced water treatment and resource recovery. Flow electrode capacitive deionization (FCDI) offers potential for selective ion removal through continuous operation. This study evaluates the performance of selective cation separation using a commercial activated carbon slurry in a multi-ion solution of monovalent (Li+, Na+, K+) and bivalent (Ca2+, Mg2+) cations. We assess ion removal and cation selectivity under different operational parameters, such as applied potential, slurry flow rate, and feed water flow rate. Our data show that bivalent cations, namely Ca2+ and Mg2+, are preferentially removal due to their higher charge-to-size ratio, aligning with hydrated ion sizes. The highest separation rate was observed for Ca2+ (5.7 μg cm−2 min−1), and the lowest for Li+ (0.2 μg cm−2 min−1). At the highest applied voltage (1.2 V), charge efficiencies reached 70 %, with an energy consumption of 41 Wh mol−1 for nearly complete cation removal. Optimal conditions were identified with a slurry flow rate of 6 mL min−1, feed water flow rate of 2 mL min−1, activated carbon content of 10 mass%, 1 mass% carbon black, and a cell voltage of 1.2 V. These findings highlight the importance of optimizing operational parameters to enhance ion removal.

Simulated warming reduced greenhouse gas emissions by lowering soil moisture in a Pinus tabulaeformis forest of the temperate zone

The forest soil carbon represents the largest carbon pool in the terrestrial ecosystem. To clarify the effect of climate warming on the soil carbon pool of a Pinus tabulaeformis plantation in the northern temperate zone, an Open-Top Chamber was used to study the effects of warming on soil temperature and moisture, soil enzyme activity, soil active organic carbon, and greenhouse gas emissions in different soil layers. The results showed that (1) warming increased the temperature and decreased the moisture content of the atmosphere and soil. Atmospheric temperature increased by 0.9°C on average, and atmospheric moisture decreased by 0.05%. (2) Warming had no significant effect on soil active organic carbon or enzyme activity, but had a significant effect on the active organic carbon content and enzyme activity in individual soil layers in individual months. (3) Warming reduced soil CO2 emissions from the control treatment, from 996.35 to 781.57 g·m−2. The soil of the P. tabulaeformis forest in Daqing Mountain is a sink of atmospheric CH4. Therefore, after the short-term warming treatment, the soil moisture was reduced; greenhouse gas emissions were significantly reduced, and the warming formed a negative feedback with soil greenhouse gas flux.

Spatial variations of annual net ecosystem productivity and its trend over Chinese terrestrial ecosystems based on spatial downscaling.

Annual net ecosystem productivity (NEP), the amount of net carbon sequestration during a year, serves as the basis of terrestrial carbon sink. Quantifying the spatial variations of NEP and its trend would enhance our understandings on the response and adaption of ecosystems to environmental change, which also serves for the regional carbon management targeting at carbon neutrality. Based on process-based model and data-driven model simulating NEP, we selected the optimal simulating NEP mostly representing NEP spatial variations with multiple site eddy covariance measurements to develop the spatial downscaling method and generate high resolution NEP data of China, which was used to examine the spatial variations of NEP and its trend and driving factors during 2000-2017. Compared with process-based model results, data-driven model simulating NEP could mostly represent the spatial variation of site measurements. The random forest regression based on climate, soil, and biological data combining with the simple scaling could successfully downscale NEP to a high spatial resolution. From 2000 to 2017, the total amount of NEP in China was (1.30±0.03) Pg C·a-1, showing a decreasing-increasing pattern with the inflection point in 2009. Chinese NEP decreased from southeast to northwest, showing a descending latitudinal distribution and an ascending longitudinal distribution, with the combined effects of climate and biotic factors. NEP trend decreased from east towards west, which was only accompanied with a slightly ascending longitudinal distribution, while photosynthetically active radiation and soil organic carbon content dominated the spatial variations of NEP trend. Therefore, the spatial patterns of generated NEP obviously differed from those of NEP trend, suggesting the obvious difference between the responses and adaptions of ecosystems to environmental changes.

Ultralight activated carbon/polyimide foam with heterogeneous interfaces for improved thermal stability, mechanical properties, and microwave absorption

AbstractThe activated carbon (AC) has been widely used in the field of electromagnetic protection because of its porous, hollow microstructure and excellent electrical conductivity. In this paper, AC was prepared through KOH activation process. The ACs/polyimide foam (PIF) composite was prepared in situ during the synthesis of PI and the ACs. In this paper, AC was prepared using the potassium hydroxide (KOH) activation process. The AC/PIF composites were prepared by mixing ACs and pyromellitic dianhydride (PMDA) with methylene diphenyl diisocyanate (MDI). The pore structure and surface morphology of the ACs were observed using nitrogen adsorption–desorption isotherms and scanning electron microscopy (SEM). After KOH activation with KOH, the surface area and total pore volume of ACs significantly increased by 79.31% and 0.9539 cm3/g, respectively, mainly were the microporous structure. X‐ray photoelectron spectroscopy (XPS) results confirmed an increase in the oxygen content of ACs after KOH activation, indicating an increase in the relative hydroxyl content on the surface. The SEM resulting of the ACs/PIF composite has a well‐developed open cell structure. Thermal gravimetric analysis (TGA) revealed that ACs significantly improved the thermal stability of the ACs/PIF composite. The compressive strength of the ACs/PIF‐3 increased from 518 to 834 KPa, significantly enhancing its mechanical properties. Simultaneously, the microwave absorption performance can be controlled and regulated by optimizing the impedance gradient of the skeleton. Results showed that when ACs constituted 8 wt% of the PIF, the real permittivity (ɛ′) and imaginary permittivity (ɛ″) of ACs‐PIF‐5 were approximately 2.03 and 0.025, respectively.

Natural grassland restoration exhibits enhanced carbon sequestration and soil improvement potential in northern sandy grasslands of China: An empirical study

Vegetation restoration is an effective measure for restoring degraded ecosystems. Soil carbon mineralization, a crucial indicator for evaluating the effectiveness of vegetation restoration, is essential in soil carbon cycling. However, the response of soil carbon mineralization to different vegetation restoration types remains unclear. In this study, grassland (Leymus chinensis and Stipa bungeana), shrubland (Corethrodendron fruticosum), and forestland (Ulmus pumila) with 20 years of consistent restoration in the Xilingol sandy grassland were selected to determine the effects of vegetation restoration types on soil carbon mineralization. The results showed that the soil cumulative carbon dioxide emissions (CCE) and microbial respiration rate (SMR) in grassland and forestland were significantly higher than those in shrubland, while soil carbon mineralization efficiency (CME) and microbial metabolic quotient (MQ) were significantly lower than those in shrubland. Furthermore, soil organic carbon (SOC) and its fractions were influenced considerably by vegetation restoration types, with grassland exhibiting the highest SOC content. The ratios of soil total effective nutrients (C/N, N/P, and C/P) and the content of active organic carbon (DOC, MBC, EOC, and POC) can effectively reflect the changes in soil carbon mineralization and the stability of SOC pools. The variations in CCE were influenced by litter biomass, macroaggregates organic carbon, mineral-associated organic carbon (MAOC), and dissolved organic carbon (DOC), while the changes in SMR were affected by aboveground biomass (AGB), soil total nitrogen and phosphorus ratios (N/P), and microaggregate organic carbon and microbial biomass carbon. The changes in CME were affected by AGB, N/P, pH, MAOC, and DOC, while the changes in MQ were influenced by AGB, N/P, DOC, MAOC, and easily oxidizable organic carbon. Given the higher carbon sequestration benefits and soil quality improvement capability of naturally restored grassland, this study suggests that grassland could be considered the primary vegetation restoration type in the Xilingol sandy grassland.

Optimized Eco-Friendly Foam Materials: A Study on the Effects of Sodium Alginate, Cellulose, and Activated Carbon.

This study focuses on optimizing the physical and mechanical properties of foam materials produced with the addition of sodium alginate as the matrix, and cellulose and activated carbon as fillers. Foam materials, valued for their lightweight and insulation properties, are typically produced from synthetic polymers that pose environmental risks. To mitigate these concerns, this study investigates the potential of natural, biodegradable polymers. Various foam formulations were tested to evaluate their density, compression modulus, and thermal conductivity. The results indicated that an increase in activated carbon content enhanced thermal stability, as indicated by higher Ti% and Tmax% values. Additionally, a higher concentration of sodium alginate and activated carbon resulted in higher foam density and compressive modulus, while cellulose exhibited a more intricate role in the material's behavior. In the optimal formula, where the sum of the component percentages totals 7.6%, the percentages (e.g., 0.5% sodium alginate, 5% cellulose, and 2.1% activated carbon) are calculated based on the weight/volume (w/v) ratio of each component in the water used to prepare the foam mixture. These results indicate that natural and biodegradable polymers can be used to develop high-performance, eco-friendly foam materials.

Synthesis and Analysis of Activated Carbon Structure from Ketaping Fruit Shell Biomass Through X-Ray Diffraction Characterization

Synthesis of activated carbon from ketaping fruit shell biomass aims to produce high-quality active carbon to be applied in various fields. Activated carbon from ketaping fruit shells is synthesized by thermal treatment. It is synthesized through two stages, namely carbonation and activation. The carbonation stage is carried out at 400oC under O2 gas flow. This aims to break down lignol cellulose into carbon with low-quality pores through incomplete combustion. The activation stage is carried out by mixing activated carbon and KOH in varying ratios of 1:1, 1:3 and 1:5 wt. It is carried out by multilevel thermal treatment at 700oC for 3.5 hours to form activated carbon with high pore quality. The activated carbon produced is then subjected to EDS characterization to see the active carbon content and XRD to see the structure of the active carbon with the characteristics of distance between layers, layer height, layer width, and number of layers. The results of EDX analysis show that the active carbon from the shell of the ketaping fruit contains 97.52% carbon and 2.48% oxygen. The results of XRD analysis show that the activated carbon surface area optimum at a molar ratio of 1:3 wt is 1,708.62 mg-1. The distance of the resulting activated carbon layer is 0.3566nm at the 002 peak and 0.2102nm at the 100 peak. The layer height and width of the active carbon layer produced at a 1:3 wt ratio were 0.5489nm and 0.3002nm. Meanwhile, the number of layers of active carbon produced is 3 layers.

Effect of Mineral Fertilizers on the Biological Activity of Soils using Direct Seeding Technology

In the field, the effect of liquid mineral fertilizers and carbamide ammonium nitrate (LMF and CAN) in the agrocenoses of peas, chickpeas, coriander and flax on the biological activity of chernozems treated for a long time using null technology was studied. Among the biological parameters, the activity of enzymes involved in the carbon cycle (invertases, dehydrogenases), the intensity of soil respiration, the number of microorganisms, and the content of active carbon were evaluated. There is a difference in the effects of fertilizers on crops and different parameters of biological activity. The biological activity of the studied soils varied depending on the type of mineral fertilizer, as well as the cultivated crop.

Activated carbon-reinforced polyurethane composite foams with hierarchical porosity for broadband sound absorption

The generation of various noise has caused severe noise pollution issues across a wide frequency spectrum, urgently requiring the development of sound-absorbing materials. Herein, we introduce composite polyurethane (PU) foams incorporating extremely nanoporous activated carbon (AC) including both meso- and macro-sized pores as an eco-friendly sound-absorbing material with superior and broadband sound absorption capabilities. The composite foam absorbs 95.8 % of the incident acoustic waves in the 2,000–5,000 Hz frequency range, i.e., the most sensitive range for the human auditory system, far outperforming pristine PU foam, which absorbs only 70.6 %. We demonstrate that sound absorption properties can be fine-tuned by adjusting the pore type and content of the AC. Significantly, the optimized composite foam structure absorbs 100 % of the incident waves at a specific frequency of 2,550 Hz. Collectively, we propose a master curve for the sound absorption properties derived from various composite foams, demonstrating that the properties can be precisely predictable and subsequently used for designing the pore characteristics and content of AC. Incorporating AC can also improve the mechanical properties of foams through interfacial adhesion phenomena. Our methodology provides valuable insights into the fabrication of composite foams with tunable sound absorption properties as a promising solution to noise pollution.

Synergistic adsorption of methylene blue with carrageenan/hydrochar-derived activated carbon hydrogel composites: Insights and optimization strategies

The study explores the use of hydrochar-derived activated carbon (AC) to improve the adsorption capacity and mechanical properties of carrageenan (CAR) hydrogel beads. Four distinct samples, with carrageenan to activated carbon ratios of 1:0 (CAR), 2:1 (CAC2), 4:1 (CAC4), and 10:1 (CAC10), were prepared. These polymeric beads underwent comprehensive evaluation for their methylene blue (MB) adsorption capacity, gel content (GC), and swelling ratio (SR). Increasing activated carbon content up to 50 % of carrageenan mass significantly enhanced GC and SR by 20.57 % and 429.24 %, respectively. Various analytical techniques were employed to characterize the composites, including FTIR, XRD, Raman Spectroscopy, BET, SEM, and EDS-Mapping. Batch adsorption tests investigated the effects of pH, contact time, dye concentration, and temperature on MB adsorption. Maximum adsorption capacities for CAR, CAC10, CAC4, and CAC2 were 475.48, 558.54, 635.93, and 552.35 mg/g, respectively, under optimal conditions. Kinetic models (Elovich and pseudo-second-order) and isotherm models (Temkin for CAR and Freundlich for CAC10, CAC4, and CAC2) fitted well with the experimental data. Thermodynamic analysis showed spontaneous, exothermic MB adsorption. Primary mechanisms include electrostatic attraction, hydrogen bonding, n-π, and π-π stacking. The study highlights enhanced adsorption capacity of carrageenan hydrogel via carrageenan/activated carbon composites, providing cost-effective wastewater treatment.

Comparison of cover crop termination methods for small-scale organic vegetable production: effect on soil fertility and health

Termination methods and the timing of the termination of the cover crops are critical factors determining the efficacy of cover crops in improving soil fertility and quality. We hypothesized that different termination methods will produce varying quantities of organic residue which will affect microbial diversity and thereby nutrient cycling and availability. The objective of this study was to compare termination methods (roller-crimper, flail mowing, rotary mowing, sickle bar mowing, and occultation using black tarps) for fall-grown cover crop combination (hairy vetch-cereal rye) under organic vegetable production. Field experiments were carried out in three consecutive years (2018–2021) and soil samples were collected from 0 to 15 cm and processed for analysis. Soil organic matter content, nutrients, health parameters, enzymes, and microbial diversity were measured. Flail mowing significantly enhanced the potentially mineralizable nitrogen, available phosphorus, and active carbon. Total Phospholipid Fatty Acid (PLFA) analysis showed a 24% increase for flail mowed, 17% for rotary mowed, and 15% for sickle bar mowed termination methods. There was a significant increase in active carbon content which ranged from 38.9% (rotary mowed), 25.4% (sickle bar mowed), 23.5% (flail mowed), 16.4% for crimper rolled method, and with 2.8% (occultation) respectively. Individual termination methods had varying effects on select enzyme activities. Results indicated that integrating cover crops has the potential to modify soil microbial community structure and increase soil enzyme activities. In this study, flail mowing appeared to be a good method for managing cover crops of choice in terms of soil microbial functionality and fertility.

Vertical distribution characteristics of soil organic carbon and vegetation types under different elevation gradients in Cangshan, Dali.

The Cangshan National Nature Reserve of Dali City was adopted as the research object to clarify the vertical distribution characteristics of soil organic carbon (SOC) and vegetation types at different elevations in western Yunnan. The contents of SOC, light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and water-soluble organic carbon (WSOC) in the 0-30 cm soil layer at different elevations (2,400, 2,600, 2,800, 3,000, 3,200, 3,400, and 3,600 m) were determined, and the above-ground vegetation types at different elevations were investigated. Results showed that the SOC content was the highest in 0-20 cm surface soil and gradually decreased with the deepening of the soil layer. It increased then decreased with the increase in elevation, and it peaked at 3,000 m. The LFOC content was between 1.28 and 7.3515 gkg-1. It exhibited a decreasing trend and little change in profile distribution. The HFOC content ranged between 12.9727 and 23.3708gkg-1; it increased then decreased with the increase in profile depth. The WSOC content was between 235.5783 and 392.3925 mgkg-1, and the response sensitivity to elevation change was weak. With the increase in elevation, WSOC/SOC and LFOC/SOC showed a similar trend, whereas HFOC presented an opposite trend. This observation indicates that the active organic carbon content at 3,600 m was lower than that at 2,400 m, and the middle elevation was conducive to the storage of active organic carbon. Meanwhile, the physical and chemical properties of soil affected the distribution of organic carbon to a certain extent. The vegetation type survey showed that the above-ground dominant species within 2,400-2,800 m were Pinus yunnanensis and Pinus armandii. Many evergreen and mixed coniferous broadleaf forests were distributed from 3,000 m to 3,200 m. Species of Abies delavayi were mainly distributed from 3,400m to 3,600m. This research serves as a reference for the study of forest soil carbon stability in high-elevation areas and plays an important role in formulating reasonable land use management policies, protecting forest soil, reducing organic carbon loss, and investigating the carbon sequestration stability of forest ecosystems.

Graphite-TiO2-doped coated sand granules for efficient continuous removal of methylene blue dye: Combining adsorption and photocatalytic degradation

This manuscript focuses on the development of coated sand granules, consisting of a thin layer of graphite doped with activated carbon (AC) and titanium oxide (TiO2) for continuous removal of methylene blue dye. The coating process was carrried out by using polyvinylpyrrolidone (PVP), AC and titanium isopropoxide (TiP). The graphitic surface was activated using 1.0 M KOH solution. Increasing the sand granules' weight from 5 to 10 g considerably enhanced adsorption capacity, with minimal improvements observed at 20 g. Calcination temperatures above 500 °C exhibited no significant impact on adsorption capacity, as samples prepared at 650 and 800 °C showed similar dye removal efficiency to the 500 °C sample. Increasing the amounts of TiP and PVP linearly improved adsorption capacity, albeit at a modest rate. The incoorporation of AC particles distinctly enhanced dye removal process, with the highest enhancement observed at 1 g AC content, further augmented by light irradiation. Flow rate studies revealed that maintaining a flow rate of 4 ml/min.cm2 resulted in continuous and stable removal (90 % removal for 90min). Increasing the flow rate to 8 ml/min.cm2 led to a linear reduction in removal rate (77 % removal after 90min), while a flow rate of 18 ml/min.cm2 showed an S-shaped adsorption isotherm, reaching 35 % removal after 90min.

Development of Sasirangan Liquid Waste Treatment System Using Ozonization Method Using Composite Ceramic Filter Media Based on Water Chestnut (Eleocharis Dulcis)

Sasirangan Liquid Waste (SLW) contains heavy metals and chemicals with BOD and COD concentrations exceeding the waste water quality standards in accordance with the Minister of Environment and Forestry Regulation Number P.16 of 2019. The aim of this research is to design and develop a SLW processing system using filter media and composite ceramics made from water chestnut (Eleocharis dulcis). Based on previous research, using the filtration method; filtration and adsorption; filtration, adsorption, sedimentation and ozonization. Filtration method can remove solid particles and sediment from water, so the water appears clearer. The water purification process that involves a filtration method using slow sand filter (SSF), which additional processes are needed either before or after the SSF is carried out. Meanwhile, the use of water chestnut has been carried out by several researchers due to its high active carbon content, namely 50.68%. In this research, we combine several methods including filtration, sedimentation, and ozonization. Water chestnut has a bound carbon content of 84.53% after being activated with an H2SO4 activator, where the largest porosity is found in ceramics with activated charcoal composite materials with variations of the H2SO4 activator. Apart from that, chestnut also has a cellulose content of 35.32% so it has the potential to be effective as a ceramic composite material in sasirangan liquid waste processing filters, especially as an adsorbent. The benefits obtained from the results of this research can be a scientific reference for the use of water chestnut as a filter media and composite ceramic.

Study Progress on the Ecological Effects of Biochar in Soil

Soil is an indispensable and important part of human production and life, and biochar, as an important form of utilization of biomass energy, can be widely used in soil conditioning and crop conditioning. Currently, a systematic framework for studying biochar's ecological impact on soil is still required. This paper briefly introduces the basic preparation method of biochar, structural characterization of biochar, and briefly describes its basic properties. By adsorbing pollutants with a high specific surface area and strong adsorption, biochar can be used to clean up heavy metal contamination in soil. It can also boost soil fertility by increasing enzyme activity and organic carbon content, as well as by reducing bulk weight and increasing cation exchange to increase soil fertility retention capacity. In addition the moderate addition of biochar can also play a positive role in crop conditioning to a certain extent. The purpose of this paper is to summarize the basic theories and research related to the study of the ecological effects of biochar in soil by introducing the typical preparation methods and basic properties of biochar, so as to facilitate the subsequent further research.

The relative dominance of surface oxygen content over pore properties in controlling adsorption and retrograde behavior of gaseous toluene over microporous carbon

The adsorption potential of activated carbon (AC) derived from macadamia nut shells (product code of Procarb-900: namely, AC-P) has been investigated using gaseous toluene as the target pollutant. The powder AC-P with high-microporosity (96%) and oxygen content (5.62%) exhibited very high adsorption capacity (214 mg·g−1) and partition coefficient (PC: 25 mol·kg−1·Pa−1) against 100 ppm (10 Pa) toluene at 99% breakthrough levels (1 atm dry N2). The factors governing toluene adsorption were explored with respect to the key variables such as surface functional groups, pore size distribution, sorbent bed mass (50, 100, and 150 mg), and particle size (i.e., 0.212–0.6 mm (powder AC: PAC)) vs. 0.6–2.36 mm (granular AC: GAC)). Accordingly, the adsorption process was physical, mainly due to the non-polar interactions (i.e., π-π interactions) between the adsorbent and adsorbate molecules. The high affinity of AC-P at low breakthrough levels was obtained through a combination of smaller particle size (PAC) and larger adsorbent mass (i.e., 150 mg) with the appearance of a very pronounced retrograde phenomenon (e.g., at < 1% breakthrough level). As such, toluene adsorption appeared to be affected more sensitively by particle size and adsorbent mass (especially at low breakthrough levels) than by high microporosity. Most importantly, the oxygen content of AC emerges as one of the key factors governing the maximum capacity, as the changes in pore volume are not crucial to explain the observed adsorption patterns of toluene.