Organic Solid Waste Research Articles

Assessing the Scope of Black Soldier Fly Larvae (Hermetia Illucens) Incorporating it into Sustainable Development

The aim of the study is to gain comprehensive understanding of the practical ways to use BSFs to convert organic solid wastes into alternative energy sources.

Composting feasibility of organic solid waste ratio of CELSS and associated microbial enhancement effects

Due to the unique environment of the Controlled Ecological Life Support System (CELSS), the type and quantity of organic solid wastes produced during long-term space missions are fixed. However, these mixed materials do not meet the indicators of conventional composting, and the vacuum in CELSS limits bio-degradation due to a shortage of functional microbes. In order to explore the feasibility of the organic solid waste ratio of CELSS and its microbial enhancement effect, composting experiments were setup to compare the actual and optimized material ratios on composting and polluted gaseous emissions, and to investigate the enhancement of microbial inoculation. The results demonstrated that the actual material ratio can be used for composting, whose degradation degree of crude protein, soluble sugar, cellulose, hemicellulose and lignin was better than the optimized treatment. The actual material ratio can also reduce 26.1% of ammonia (NH3) and 66.8% of methane (CH4) emissions. They were attributed to the carbon source in the actual materials, which resulted in higher species abundance, uniformity, and dominance of the microbial community and a stronger overall utilization ability. Moreover, the inoculation of VT microbial agent can further increase the diversity of microorganisms and prolong the duration of high activity, which helps to strengthen the degradation of crude fat, cellulose and lignin, and reduced 50.7% of hydrogen sulfide (H2S) and 33.2% of nitrous oxide (N2O) emissions. Therefore, it is recommended that the aerobic composting technology in CELSS use the proportion of actual organic solid waste to match the material and add VT microbial agent.

Trichoderma yunnanense Isolated from Patchouli plant as a Bio-Conversion Agent for Solid Organic Waste

Trichoderma yunnanense Isolated from Patchouli plant as a Bio-Conversion Agent for Solid Organic Waste

Dose-specific Toxicity of Naphthalene (Polycyclic Aromatic Hydrocarbon) and Subsequent Recovery by Humic Feed-O-Fert on Anabas testudineus (Bloch): Blood Biochemical and Morphological Introspections

Polycyclic aromatic hydrocarbons (PAHs) are pervasive contaminants in aquatic ecosystems, yet their specific effects on blood pathophysiology, including alterations in blood biochemical and morphological introspections, remain largely unexplored. As consequence, the present study is aimed to record the toxicity of naphthalene exposure for 21-d under two selected doses 0.7075mg/L (T1) and 1.415mg/L (T2), i.e., 25 and 50% of LC50 value [2.83mg/L] respectively and subsequent recovery with one improved organic solid waste, feed-promoter Humic feed-o-fert (HF) of 0.5g/L for the same duration of 21-d. The results showed significant increment in values in blood biochemical parameters, viz., cholesterol (CHOLES), glucose (GLU), glutamine pyruvic transmission (GPT), calcium (Ca), alkaline phosphatase (ALP), high density lipoprotein (HDL) and low density lipoprotein (LDL), and some displayed decreasing trend like protein (PRO), albumin (ALB) and triglyceride (Trig) under this exposure. During recovery phase with HF, the nature of biochemical changes became reversed showing significant restoration and repairment in comparison to naphthalene treatment. Morphological alterations of blood cells revealed maximum changes and appearance, such as tear drop-like cells (Tr), sickle cells (Sk), swelled cells (Sc) and vacuolated cells (Va) under two doses of exposure in 21-d, but under recovery with HF the cells approached towards regaining the normal contour of leucocytes (L), erythrocytes (Er) and tear drop like cells (Tr). So, it can be inferred that Humic feed-o-fert (HF) here played an important role to resist the haematological impairments in fish against the naphthalene (PAH) exposure. Further, Humic feed-o-fert (HF) may contribute in aquatic ecosystem restoration against the environmental contaminants, especially PAHs in aquaculture.

Enhanced Electromagnetic Energy Conversion in an Entropy‐driven Dual‐magnetic System for Superior Electromagnetic Wave Absorption

AbstractThermochemical conversion is a highly effective method for upgrading organic solid wastes into high‐value materials, contributing to carbon neutrality and peak, carbon emission goals. It also serves as a pathway to develop energy‐efficient electromagnetic wave absorbing (EMWA) materials. In this study, fish skin to successfully in situ nitrify Prussian Blue into Fe3N under external thermal driving condition, resulting in high saturation magnetization is utilized. The resulting Fe3N@C demonstrates outstanding EMWA property, achieving a minimum reflection loss of −71.3 dB. Furthermore, by introducing cellulose nanofiber, a portion of the iron nitride is transformed into iron carbide, resulting in Fe3C/Fe3N@C. This composite exhibits enhanced EMWA properties owing to wider local charge redistribution and stronger electronic interactions, achieving an effective absorption bandwidth (EAB) of 6.64 GHz. Electromagnetic simulations and first‐principles calculations further elucidate the EMWA mechanism, and the maximum reduction value of the radar‐cross section reached 37.34 dB·m2. The design of multilayer gradient metamaterials demonstrated an ultra‐broadband EAB of 11.78 GHz. This paper presents an efficient strategy for atomic‐level biomass waste utilization to prepare Fe3N, provides novel insights into the conversion between metal nitrides and metal carbides, and offers a promising direction for the development of advanced EMWA materials.

Remoción de cromo (VI) de agua residual de curtiembre empleando biomasa orgánica vegetal en un reactor biológico secuencial aerobio

[Introduction]: In the removal of chromium (VI) from tannery wastewater, physicochemical methods are the most used. However, these require high operating costs, and worse still, generate secondary pollutants that again require complementary treatments for their elimination. Given this, the applicability of plant organic biomass (VOB) emerges as an environmental alternative based on the adsorption of chromium (VI), the simplicity of obtaining it, the reduction as waste and, above all, it does not generate secondary pollutants. [Objective]: Use VOB waste in an aerobic sequential biological reactor (SBR) for the removal of chromium (VI) in the treatment of tannery wastewater. [Methodology]: 3 aerobic SBR systems were implemented; 2 controls (SBR1 and SBR2) and 1 study subject (SBR+VOB). Each system was fed with tannery wastewater (18 L) and connected to an aeration system (12.7 L/min). The bacterial inoculum, a fundamental part of an SBR system, was obtained from the selective culture of chromium (VI) reducing bacteria (RBCrVI) taken from the wastewater under study, and integrated into SBR2 and SBR+VOB at 0.6 g/L. The VOB was obtained from Stenotaphrum secundatum residues, fragmented, sieved, sterilized and integrated into the SBR+VOB at 1.5 g/L. [Results]: The SBR+VOB system achieved the highest percentage of chromium (VI) removal (93 %), followed by SBR2 (80.1 %), and finally SBR1 (2.8 %). With respect to COD and TSS, the statistical test (Tukey) showed that there was no significant difference between the system under study and the controls, recording COD removal percentages ranging from 87.8 % to 88.4 %, and TSS ranging from 63.8 % to 69.2 %. [Conclusions]: The viability of using VOB waste to remove chromium (VI) in the treatment of tannery wastewater has been evidenced. The results of this research create a promising panorama to mitigate the effects derived from inadequate management of tannery wastewater and organic solid waste.

Catalytic pyrolysis of hydrolyzed lignin using HZSM-5/MCM-41 supported transition-metal to produce monocyclic aromatic hydrocarbons

Hydrolyzed lignin (HL), one kind of organic solid wastes, comes from the production of hydrolysis of lignocellulosic biomass for high-value chemicals, unsuitable treatment of which not only meaning the waste of resources but also resulting environmental pollution. The pyrolysis of HL has the problem of high oxygen-containing compounds and low hydrocarbons in the products. The HZSM-5/MCM-41 (HM) meso-microporous composite catalyst, containing nickel and molybdenum, was synthesized through impregnation to enhance the production of monocyclic aromatic hydrocarbons (MAHs) during the in-situ catalytic pyrolysis of hydrolyzed lignin. Different transition metals loaded on composite molecular sieves were prepared for comparison. The relationship between catalyst structure and pyrolysis efficiency was studied based on characterization techniques including SEM, BET, and XRD. This study investigated the catalytic properties of modified composite molecular sieves with Ni and Mo at different loaded ratios on the pyrolysis of hydrolyzed lignin. Results indicated that HM loaded with different metals had different catalytic pyrolysis selectivity. The relative yield of MAHs on 3 %Ni-HM was the highest, at 27.78 %, while that of phenolic on 5 %Mo-HM was 51.02 %. Thus, by modifying the co-loading ratios between Ni and Mo, the combined catalytic pyrolysis of hydrolyzed lignin was performed, achieving a 39.24 % yield of MAHs on the catalyst Mo1Ni2-HM, markedly surpassing the 17.69 % yield from unaltered HZSM-5/MCM-41. In addition, the improvement of active sites was caused by transition metals loaded and the synergistic effect between bimetals enhanced the catalytic activity and stability. HZSM-5/MCM-41 loaded with metal oxides promoted the depolymerization of macromolecules in the intermediate products of pyrolysis, and thus improved the relative yield of MAHs among pyrolysis products of hydrolyzed lignin.

Modeling and forecasting biogas production from anaerobic digestion process for sustainable resource energy recovery

Anaerobic digestion (AD) is one of the most extensively accepted processes for organic waste cleanup, and production of both bioenergy and organic fertilizer. Numerous mathematical models have been conceived for modeling the anaerobic process.In this study, a new modified dynamic mathematical model for the simulation of the biochemical and physicochemical processes involved in the AD process for biogas production was proposed. The model was validated, and a sensitivity analysis based on the OAT approach (one-at-a-time) was carried out as a screening technique to identify the most sensitive parameters. The model was developed by updating the bio-chemical framework and including more details concerning the physico-chemical process. The fraction XP was incorporated into the model as a particulate inert product arising from biomass decay (inoculum). New components were included to distinguish between the substrate and inoculum, and a surface-based kinetics was used to model the substrate disintegration. Additionally, the sulfate reduction process and hydrogen sulfide production have been included. The model was validated using data extracted from the literature. The model's ability to generate accurate predictions was testified using statistical metrics. The model exhibited excellent performance in forecasting the parameters related to the biogas process, with measurements falling within a reasonable error margin. The relative absolute error (rAE) and root mean square error (RMSE) were both less than 5 %, indicating a high ability of the current model in comparison with the literature. Additionally, the scatter index (SI) was below 10 %, and the Nash-Sutcliffe efficiency (NES) approached one, which affirms the model's accuracy and reliability. Finally, the model was applied to investigate the performances of the AD of food waste (FW). The findings of this study support the robustness of the developed model and its applicability as a virtual platform to evaluate the efficiency of the AD treatment and to forecast biogas production and its quality, CO2 emission, and energy potential across various organic solid waste types.

Effects of high solid content and straw proportion on volatile fatty acids production from straw, sludge and food wastes: performance and microbial community characteristics

Anaerobic digestion (AD) is an efficient technology for treating organic solid wastes, and the volatile fatty acids (VFAs) produced during AD have significant value due to their wide range of applications and higher added value compared to methane. This study investigated the long-term effects of high solid content and straw proportion in mixed substrates (straw, sludge, and food wastes) on VFAs production through semi-continuous reactors under thermophilic and mesophilic conditions. Results showed that both reactors achieved a maximum VFAs concentration of ~ 22 g/L as the straw proportion increased to 50%. Acetate (48.3 – 64.5%) was the main component of produced VFAs in both reactors, while butyrate and propionate production in thermophilic temperature were superior compared to mesophilic conditions. Microbial community analysis revealed that Defluviitoga plays a pivotal role in acidogenesis within both reactors; besides, unclassified Hungateiclostridiaceae and Caproiciproducen were found to be dominant in thermophilic reactor, while Lachnospiraceae_NK3A20_group and Rikenellaceae_RC9_gut_group were essential for VFAs production under mesophilic conditions. These findings provide valuable insights for the biotechnological exploration of acidogenic fermentation for large-scale mechanized production of VFAs from agricultural wastes.

Organic municipal solid waste derived hydrogen production through supercritical water gasification process configured with K2CO3/SiO2: Performance study

Cities worldwide face a significant public health and environmental challenge in handling municipal solid waste (MSW). This research exposed an effective utilization of MSW as the source for hydrogen production via a supercritical water gasification process under 450–650 °C at 15–45 min processing time. The impacts of gasification temperature and processing time on the functional properties of hydrogen production are studied. Its results are compared to identify the optimum processing temperature and processing time to adopt the system. Integrating 3 wt% silicon dioxide (SiO2) nanoparticles/3 wt% of potassium carbonate (K2CO3) enhances hydrogen production by increasing the catalyst's surface area and improving the stability of active sites, leading to more efficient gasification reactions. Increasing the gasification temperature from 450 to 650 °C significantly raises the hydrogen molar fraction and gas yield with peak gasification efficiency (GE) and hydrogen efficiency (HE) values. The gasifier functioned with catalyst (3 wt% K2CO3/SiO2) under 650 °C gasification temperature and 45min gasification time influenced better output responses like improved hydrogen gas yield of 63.7 mol/kg, higher gasification efficiency of 59.8 %, better hydrogen efficiency (63.4 %) and increased carbon conversion efficiency of 63.4 and 42.5 % respectively.

The new strategies of using nitrogen and iron modified hydrochar to enhance methane production during co-anaerobic digestion of cow manure and corn straw

The traditional hydrochar shows limited ability to promote methane production during anaerobic digestion of organic solid waste. This study explored the effect of hydrochar modified using nitrogen and iron on methane production and microbial communities during the co-anaerobic digestion (co-AD) of cow manure and corn straw. Compared with unmodified hydrochar prepared from biogas residue (BHC), iron and nitrogen-iron modified hydrochar (BHC-Fe and BHC-N) improved the specific surface area (SSA) and proportion of oxygen-containing functional groups (OCFGs) related to direct interspecies electron transfer. The results showed that, compared to the control group (without hydrochar addition), the total methane production increased by 30 %, 36 %, and 46 % in the BHC, BHC-Fe, and BHC-N groups, respectively. The addition of modified hydrochar improved the microbial diversity and enrichment of Methanobacterium, Methanobrevibacter, and Methanosarcina spp., with BHC-N being the most effective. COD and Methanobrevibacter showed the highest explanation for methane production in AD performance indexes and archaeal genera (66.4 % and 29.3 %). Surface OCFGs of hydrochar had a more significant and direct effect on methane production than the SSA and archaeal genera. Therefore, the addition of BHC-N contributes more to promote methane production during the co-AD of cow manure and corn straw. This study could provide the new strategies for improving the co-AD of cow manure and corn straw performance, further promoting the resourcing and disposal of cow manure and corn straw.

Alleviating heavy metal accumulation and pathogens’ abundance through processing proper ratio of duck feces and food waste by Black solider fly larvae

ABSTRACT The efficient and sustainable utilization of duck feces is critically essential in China, given its expansive livestock and poultry breeding industry. While the use of black solider fly (BSF) larvae for composting duck feces has gained recognition, public apprehensions concerning the nutritional value and safety of the resultant by-products remain prevalent. This study presents the inaugural assessment of potential risks and quality of resource-based products derived from various proportions of food waste and duck feces processed by BSF larvae. Our findings indicate that mixed substrate A2 yielded BSF larvae with the highest level of N and P, alongside the lowest accumulation of As, Pb and Cd, as well as reduced total pathogen abundance in the remaining substrate when compared to other mixed substrates (A3 and A4). This suggests that an appropriate nutrient composition ratio in the substrates not only facilitated effective conversion but also diminished heavy metal accumulation by BSF larvae. Additionally, a significant negative correlation was observed between N, P, and Cd (R 2 = −0.989, −0.996, p < 0.01), implying that elevated N and P concentrations in BSF larvae may enhance immune function and while further mitigating heavy metal enrichment. Overall, achieving a suitable nutrient ratio of duck feces and food waste is imperative for their scientific and safe utilization, providing valuable insights for the bioconversion of organic solid waste through BSF larvae.

Enhancement of Biocrude Quality Using Fecal Sludge and Organic Solid Waste Through Two-Stage Hydrothermal Liquefaction Technique

The escalating global challenge of managing unmanaged fecal sludge (250-300 million tonnes/year) and organic solid waste (600-700 million tonnes/year) necessitates innovative and sustainable waste-to-energy solutions. Hydrothermal liquefaction (HTL) of FS &amp; OSW to produce biocrude has been seen as a double-edged sword to substitute fossil fuel and address the issues relating to unmanaged waste (GHG emission, global warming, climate change). Through this study, an approach was taken to improve the biocrude production and enhance the biocrude quality by introducing a two-stage heating in HTL of FS and OSW separately. Four different runs were comprised in this study where one run was in conventional one stage, at 320℃ for 60 min. In terms of the other three runs, in the first stage, 100, 200, and 300℃ were retained for 30 min respectively and the second stage was conducted at 320℃ for 30 min. Results indicate a substantial improvement in biocrude yield of 15% &amp;18% through two-stage heating during HTL (30 min at 200℃, and then 30 min at 320℃) compared to conventional single-stage HTL processes of FS &amp; OSW respectively with a biomass conversion rate of 70%. From the analysis of biocrude maturity &amp; intensity of oil we observe a high potential for crude oil formation being classified as Kerogen type I. GC-FID shows that increasing heat in the first stage tends to produce a lighter fraction (at 300℃ in the first stage produces biocrude with a lighter fraction&gt;80% from FS &amp; OSW feedstocks) in biocrude. In addition to improving the overall efficiency of converting organic waste to biocrude, the two-stage system offers a more flexible platform that allows the biofuel composition to be customized to match the needs of individual applications. The results show that a two-stage HTL process is a feasible and effective technique for converting difficult waste streams into biofuels, with implications for both environmental sustainability and energy security. Journal of Engineering Science 15(1), 2024, 95-105

Catalytic Valorization of Organic Solid Waste: A Pilot-Scale Run of Sugarcane Bagasse

Organic solid waste treatment is crucial for enhancing environmental sustainability, promoting economic growth, and improving public health. Following our previous organic solid waste upgrading technique, a further two-step pilot-scale run, using sugarcane bagasse as the feedstock, has been successfully conducted with long-term stability. Firstly, the sugarcane bagasse was treated under mild conditions (400 °C and 1 bar of CH4), and this catalytic Methanolysis treatment resulted in a bio-oil with a yield of 60.5 wt.%. Following that, it was subjected to a catalytic Methano-Refining process (400 °C and 50 bar of CH4) to achieve high-quality renewable fuel with a liquid yield of 95.0 wt.%. Additionally, this renewable fuel can be regarded as an ideal diesel component with a high cetane number, high heating values, a low freezing point, low density and viscosity, and low oxygen, nitrogen, and sulfur contents. The successful pilot-scale catalytic upgrading of sugarcane bagasse further verified the effectiveness of this methane-assisted organic solid waste upgrading technique and confirmed the high flexibility of this innovative technology for processing a wide spectrum of agricultural and forestry residues. This study will shed light on the further valorization of organic solid waste and other carbonaceous materials.

Assessing the degradability of biodegradable-packaging base material through the insertion of organic solid waste deriving from composting process

The intensification of the use of plastic materials in recent decades has caused several environmental impacts, becoming direct incentives for research and development of alternatives that minimize the massive amount of plastics used by societies. In this context, so-called biodegradable materials emerge, with emphasis on starch-based compounds, which, although they have limited mechanical properties and low water resistance, allow the mixture with various reinforcing agents, in order to overcome the deficiencies for their application in larger scales without detracting from its focus on biodegradability. In this sense, the present study aimed to evaluate the biodegradability of a starch-based biopolymer, with the addition of different proportions of malt bagasse, this residue from the production process of beer; evaluating and monitoring parameters of the composting process of this mixture with organic solid waste. Biodegradation was determined from the visual assessment of the material, monitoring parameters such as pH, temperature, humidity and organic matter, being recorded in an electronic spreadsheet for descriptive analysis. The results obtained, when compared to the control composting unit, indicate a lower biological activity on the compost, consequently, a greater resistance to biodegradation. After three weeks of composting, it was difficult to identify the material and after four weeks, it was not possible to identify the biopolymer, indicating its biodegradation and incorporation into the substrate. It was observed that the material showed changes in its mechanical properties during composting. It is concluded that the material is totally biodegradable in all malt bagasse compositions, under composting conditions.

Enhancing oil production via radical reactions during hydrothermal coliquefaction of biomass model compounds and plastics: A molecular dynamic simulation study

Recently, hydrothermal coliquefaction of biomass and plastic waste has attracted considerable research interest. However, there is a notable gap in understanding the fundamental reaction mechanisms between biomass and plastics during coliquefaction. This study focused on the coliquefaction of biomass model compounds and plastic polymers using ReaxFF molecular dynamics simulations under both subcritical and supercritical water conditions. Molecular-level tracking and probing of the reaction mechanisms between biomass model compounds and plastics were conducted to purposefully enhance oil production. The study observed related radical reactions between by-product molecules, with detailed mechanisms primarily involving (1) ▪OH radicals released by aqueous phase molecules from biomolecules, transferring as H2O molecules and facilitating plastic depolymerization, and (2) C1–C4 radicals in the gaseous phase, emitted from biomolecule and plastic, colliding and subsequently recombining to form oil molecules. Moreover, the yield of multiple products from various mixtures were evaluated by considering the key reaction parameters including reaction temperature and feedstock blended ratio. An exploration into the effect of coliquefaction on oil yield was conducted to precisely identify the optimal coliquefaction conditions. The positive effect of coliquefaction was more pronounced between biomass model compounds and aromatic polymers compared to aliphatic polymers. Analysis of reaction mechanisms and product outcomes has shown that hydrothermal coliquefaction is a viable approach to improving oil production from multi-source organic solid waste.

Sustainable pyrolytic carbon negative electrodes for sodium-ion batteries

Considering both sustainability and potential applications in various industrial sectors, pyrolytic carbon from the recycling of organic solid wastes can play a significant part in the unfolding energy revolution. Further innovations in circular-economy waste loops can facilitate higher economic benefits and lower environmental impacts, where a number of opportunities for improving pyrolytic carbon by choices of precursors, easy regulation of pyrolysis conditions and potential post-treatments. Here we propose a method to synthesize sustainable high-quality nanotube-like pyrolytic carbon using waste pyrolysis gas from the decomposition of waste epoxy resin as precursor, and conduct the exploration of its properties for possible use as a negative electrode material in sodium-ion batteries. The obtained pyrolytic carbon shows better cycling and rate performance than benchmark commercial hard carbon, retaining ∼105 mA h g−1 after 2000 cycles at 100 mA g−1 and exhibiting ∼57 mA h g−1 at 1 A g−1. Since the slope-dominated nature of pyrolytic carbon leads to high performance dependence on defects and pore structure, we therefore also investigate the preferred design of pore structure via pore-forming by post-treatment. It is found that reversible adsorption/desorption on defect sites and optimal pore structure are highly needed for pyrolytic carbon toward practical applications. This work highlights the potential of waste pyrolysis gas itself as a valuable feedstock for the production of value-added carbon materials.

Rapid Reduction of Phytotoxicity in Green Waste for Use as Peat Substitute: Optimization of Ammonium Incubation Process.

The rapid growth of the horticultural industry has increased demand for soilless cultivation substrates. Peat, valued for its physical and chemical properties, is widely used in soilless cultivation. However, peat is non-renewable, and over-extraction poses serious ecological risks. Therefore, sustainable alternatives are urgently needed. Ammonium incubation, a novel method to reduce phytotoxicity, offers the potential for green waste, a significant organic solid waste resource, to substitute peat. This study optimized the ammonium incubation process to reduce green waste phytotoxicity. It systematically examined different nitrogen salts (type and amount) and environmental conditions (temperature, aeration, duration) affecting detoxification efficiency. Results show a significant reduction in phytotoxicity with ammonium bicarbonate, carbonate, and sulfate, especially carbonate, at 1.5%. Optimal conditions were 30 °C for 5 days with regular aeration. Under these conditions, ammonium salt-treated green waste significantly reduced total phenolic content and stabilized germination index (GI) at a non-phytotoxic level (127%). Using treated green waste as a partial peat substitute in lettuce cultivation showed promising results. This low-cost, low-energy method effectively converts green waste into sustainable peat alternatives, promoting eco-friendly horticulture and environmental conservation.

Photocatalytic removal of rhodamine B using a novel g–C3N4–organic solid waste biochar composite: Pathway, key factors, and mechanism

Over the past decades, water pollution caused by organic dyes has attracted extensive attention. The development of efficient, environmental friendly photocatalysts is a promising route for wastewater purification. Herein, a novel wild jujube shell derived biochar/g-C3N4 (BC/CN) composite has been prepared via a one-step calcination route. Although the specific surface area (9.37 m2/g) and pore size (14.57) of the BC/CN composite are smaller than those of g-C3N4, it exhibits enhanced photocatalytic activity. Especially, the 0.25-BC/CN composite (sour jujube shell powder/melamine ratio = 0.25) displays excellent photocatalytic activity, and can degrade ∼97.1 % of RhB under 40 min light irradiation, which is ∼46.51 times to that of pure g-C3N4. The actives species of h+, ·OH, ·O2− and 1O2 active species play the important roles in the photocatalytic system of the BC/CN composite. The results mechanistic study demonstrates that the enhanced photocatalytic activity of the BC/CN composite can be mainly attributed to the improved light absorption and charge separation efficiency of the catalyst. This work provides a simple method for preparing of novel highly efficient g–C3N4–based photocatalyts for wastewater purification, and provides a new idea for the recycling, and high-value utilization of the organic solid waste from traditional Chinese medicine.

Unlocking the photothermal conversion capacity of lignin and lignin-derived materials

Lignin is the most prevalent polyphenolic organic solid waste generated by the pulping and biorefining industries. It confers upon woody biomass a remarkable combination of physical, chemical, and biological resilience, while simultaneously exhibiting considerable potential for photothermal conversion. In recent years, the utilization of technical lignin and lignin by-products to develop photothermal materials has emerged as a research hotspot. This review introduces the industrial separation processes and characterization of different types of lignin, highlighting the chemical structures of lignin and its derivatives linked to their photothermal conversion mechanisms. The evaluation pathways for photothermal conversion are summarized and critically assessed, as guided by mathematical descriptions of best practices in lignin-derived materials. This review covers and reflects on recent and emerging advances in materials and energy sciences that demonstrate how lignin can be utilized to maximize solar-to-thermal conversion and versatility in desalination, electricity generation, therapy, and intelligent and environmentally friendly building materials. Finally, the challenges and proposed future directions for the development of lignin-derived photothermal materials are identified with the objective of challenging the prevailing notion that lignin is merely an organic solid waste.