Breakthrough of Carbon-Ash Recalcitrance in Hydrochar via Molten Carbonate:Engineering Mineral-Rich Biowaste Toward Sustainable Platform Carbon Materials

The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash remains elusive and hinders the availability of hydrochar.Herein,we propose a facile strategy for breaking the rigid structure of carbon-ash coupled hydrochar using phase-tunable molten carbonates.A case system was designed in which livestock manure and NaHCO3 were used to prepare the activated hydrochar,and NH3 served as the target contaminant.Due to the redox effect,we found that organic fractions significantly advanced the melting temperature of Na2CO3 below 800℃.The Na species steadily broke the carbon-ash interaction as the thermal intensity increased and transformed inorganic constituents to facilitate ash dissolution,rebuilding the hydrochar skeleton with abundant hierarchical channels and active defect edges.The surface polarity and mesopore distribution collectively governed the five cycles NH3 adsorption attenuation process.Manure hydrochar delivered favorable potential for application with a maximum overall adsorption capacity of 100.49 mg·g^(-1).Integrated spectroscopic characterization and theoretical computations revealed that incorporating NH3 on the carbon surface could transfer electrons to chemisorbed oxygen,which promoted the oxidation of pyridine-N during adsorption.This work offers deep insight into the structure function correlation of hydrochar and inspires a more rational design of engineered hydrochar from high-ash biowaste.

Effect of rare earth and Mn elements on the corrosion behavior of extruded AZ61 system in 3.5 wt%NaCl solution and salt spray test

In this study,multiple addition of rare earth(RE)and manganese(Mn)to AZ61 was conducted aiming to find out the influence to corrosion resistance.AZ61 containing different amounts of RE and Mn was investigated by electrochemical measurement in condition of 3.5 wt%NaCl solution at 25°C.Gravimetric measurement was conducted in 5 wt%salt spray at 35°C and 3.5 wt%NaCl solution at 25°C.Samples were characterized by SEM,EDS,OM and XRD.The result shows that with RE addition Al8Mn5 in AZ61 changed into Al10RE2Mn7.The quantity ofβphase is reduced significantly.The multiple addition of RE and Mn improved the corrosion resistance of AZ61.When the ratio of Mn and RE is 0.3,alloy has the best property of corrosion resistance.In addition,the composite addition removed the impurity elements in AZ61 especially Fe.

The Role of Biochar to Enhance Anaerobic Digestion: A Review

Biochar,one of the products of thermochemical conversion of biomass,possesses specific physiochemical properties such as conductivity,pore adsorption,surface functional groups,and cation exchange capacity.Anaerobic digestion(AD)as a classical bio-wastes conversion technology,suffers from inhibitions,process instability,and methanogenic inefficiency which limit its efficiency.With the advantages of pH buffering,functional microbes enrichment,inhibitors alleviating,and direct interspecies electron transfer(DIET)accelerating,biochar suggests a promising application as additives for AD.Herein,this paper reviewed the noting physicochemical properties of biochar,and discussed its roles and related mechanisms in AD.Further,this paper highlighted the advantages and drawbacks,and pointed out the corresponding challenges and prospects for future research and application of biochar amending AD.

Renewable biomass reinvigorates sustainable water-energy nexus

The water-energy nexus has garnered worldwide interest.Current dual-functional research aimed at coproducing freshwater and electricity faces significant challenges,including sub-optimal capacities("1+1<2"),poor inter-functional coordination,high carbon footprints,and large costs.Mainstream water-toelectricity conversions are often compromised owing to functionality separation and erratic gradients.Herein,we present a sustainable strategy based on renewable biomass that addresses these issues by jointly achieving competitive solar-evaporative desalination and robust clean electricity generation.Using hydrothermally activated basswood,our solar desalination exceeded the 100% efficiency bottleneck even under reduced solar illumination.Through simple size-tuning,we achieved a high evaporation rate of 3.56 kg h^(-1)m^(-2)and an efficiency of 149.1%,representing 128%-251% of recent values without sophisticated surface engineering.By incorporating an electron-ion nexus with interfacial Faradaic electron circulation and co-ion-predominated micro-tunnel hydrodynamic flow,we leveraged free energy from evaporation to generate long-term electricity(0.38 W m^(-3)for over 14 d),approximately 322% of peer performance levels.This inter-functional nexus strengthened dual functionalities and validated general engineering practices.Our presented strategy holds significant promise for global human–society–environment sustainability.

A data-based review on norfloxacin degradation by persulfate-based advanced oxidation processes:Systematic evaluation and mechanisms

Persulfate-based advanced oxidation processes(AOPs)have obtained increasing attention due to the generation of sulfate radical(SO_(4)-)with high reactivity for organic contaminants degradation,Numerous activation methods have been used to activate two common persulfates:peroxymonosulfate(PMS)and peroxydisulfate(PDS).However,the comparisons of activation methods and two oxidants in the comprehensive degradation performance of the target contaminant are still limited.Thus,taking norfloxacin(NOR)as the target contaminant,we proposed five key parameters(the observed pseudo-first-order rate constant,kobs;average mineralization rate,rm;utilization efficiency of catalyst,Ucat;utilization efficiency of oxidant,Uox;and net utilization efficiency of oxidant,Uox')to quantify the comprehensive degradation performance of NOR.The irradiation affected target pollutants,catalysts,and oxidants,leading to an improved degradation performance of NOR.Various heterogeneous catalysts were compared in terms of the key elements contained.Fe,Co,and Mn-based materials performed better,while carbon-based catalysts performed poorly on NOR degradation.The overall degradation performance of NOR was different for PMS and PDS,which can be ascribed to their varied reaction pathways towards NOR,but stemmed from different properties of PMS and PDS.Besides,the effect of pH on the degradation efficiency of NOR was investigated.A neutral solution was optimal for PMS system,while an acidic solution worked better for PDS system.Finally,we analyzed the molecule structure of NOR by density functional theory(DFT)calculation to study the sites easy to attack.Then,we summarized four typical degradation pathways of NOR in SO_(4)^(-)-based AOP systems,including defluorination,piperazine ring cleavage,piperazine ring oxidation,and quinoline group transformation.

Waste bio-tar based N-doped porous carbon for supercapacitors under dual activation:performance,mechanism,and assessment

Bio-tar extra-produced from biomass pyrolysis is prone to pose a threat to environment and human health.A novel N-doped porous electrode from bio-tar was produced under dual-activation of urea and KOH in this study.Onepot dual-activation played significant roles in N-functional group and micro-mesoporous structure,which resulted in the carbon material with the highest of nitrogen content(4.08%)and the special surface area(1298.26 m^(2)·g^(−1)).Specifically,the potential mechanisms of pore formation and N-doping in the one-pot dual-activation strategy were also proposed as a consequence,the one-pot dual-activated carbon material displayed excellent electrochemical performance with the highest capacitance of 309.5 F·g^(−1) at 0.5 A·g^(−1),and the unipolar specific capacitance remained with cyclic characteristics of 80.1%after 10,000 cycles in two-electrode symmetric system.Furthermore,the one-pot dual-activation strategy could create a profit of$1.64-$2.38 per kilogram of bio-tar processed without considering the initial investment and labor costs,which provides new perspectives for the utilization of waste bio-tar.

Heteroatom-doped biochar devised from cellulose for CO_(2) adsorption:a new vision on competitive behavior and interactions of N and S

Biochar,as a potential CO_(2) adsorbent,is of great significance in addressing the problem of global warming.Previous studies have demonstrated that the CO_(2) adsorption performance of biochar can be improved by nitrogen and sulfur doping.Co-doping can integrate the structure and function of two elements.However,the physicochemical interaction of nitrogen and sulfur during doping and the CO_(2) adsorption process remains unclear in co-doped biochar.In this study,the heteroatom-doped biochar was prepared with different additives(urea,sodium thiosulfate,and thiourea)via hydrothermal carbonization,and the physicochemical interaction of nitrogen and sulfur in co-doped biochar was investigated extensively.The findings revealed that nitrogen and sulfur competed for limited doped active sites on the carbon skeleton during the co-doping process.Interestingly,thiourea retained the amino group on the surface of biochar to a great extent due to carbon-sulfur double bond breaking and bonding,which facilitated the formation of pore in the activation process.Significantly,co-doping had no significant improvement effect although nitrogen and sulfur doping separately enhanced the CO_(2) adsorption performance of biochar by 11.9%and 8.5%.The nitrogencontaining and sulfur-containing functional groups in co-doped biochar exhibited mutual inhibition in the process of CO_(2) adsorption.The findings of this study will have pertinent implications in the application of N/S co-doped biochar for CO_(2) adsorption.

LIVESTOCK AND POULTRY MANURE MANAGEMENT FROM THE PERSPECTIVE OF CARBON NEUTRALITY IN CHINA

The rapid growth of the livestock and poultry production in China has led to a rise in manure generation,which contributes to the emissions of GHGs(greenhouse gases including CH_(4),N_(2)O and CO_(2))and other harmful gases(NH_(3),H_(2)S).Reducing and managing carbon emissions has become a critical global environmental imperative due to the adverse impacts of GHGs.Unlike previous reviews that focused on resource recovery,this work provides an unique insight of transformation from resource-oriented manure treatment to integration of resource recovery with pollution reduction,carbon accounting and trading,focusing on the sustainable development of manure management system.Considering the importance of accounting methodologies for carbon emission and trading system toward carbon neutrality society,suggestions and strategies including attaching high importance to the development of more accuracy accounting methodologies and more practical GHG emission reduction methodologies are given in this paper.This work directs the establishment of carbon reduction methodologies and the formulation of governmental policies for livestock and poultry manure management system in China.

VALORIZATION OF LIVESTOCK WASTE AND CARBON NEUTRALITY

Livestock production has rapidly developed along with improvements in living standards and people’s desire for a better life.Intensive livestock production is important to guarantee supply of meat,eggs and milk,and even vegetable production,in the modern society of China.Recently,the Ministry of Agriculture and Rural Affairs jointly with the National Development and Reform Commission,the Ministry of Finance,and the Ministry of Natural Resources in China formulated and released the National Modern Facility Agriculture Construction Plan(2023‒2030)[1],which proposed the construction of modern animal husbandry facilities with efficient and intensive operations,encouraging the development of three-dimensional facility farms for pigs and poultry,and promoting using multistory buildings according to local conditions.However,large-scale livestock and poultry farms have faced many challenges impacting its green and sustainable development,such as production environment,air quality,manure and sewage treatment and resource utilization.

Treatment of recalcitrant wastewater and hydrogen production via microbial electrolysis cells

A large amount of real complex wastewaters are generated every year,which leads to a great environmental burden.Various treatment technologies were deployed to remove the contaminants in the wastewaters.However,these actual wastewaters have not been sufficiently treated due to their complex properties,high-concentration organics,incomplete utilization of hard-biodegradable substrates,the high energy input required,etc.Recently,microbial electrolysis cells(MECs),a great potential technology,has emerged for various wastewater treatment,because not only do they demonstrate satisfactory performance during wastewater treatment,but they also generate renewable H2 as a clean energy carrier.Unlike previous reviews,this review introduced the characteristics of every complicated wastewater,and focused on analyzing and summarizing MEC development for wastewater treatment.The performances of MECs were systematically reviewed in terms of organics removal,H2 production,Columbic efficiency,and energy efficiency.MEC performances for treating actual complex wastewaters and producing H2 can be optimized through operation parameters,electrode materials,catalyst materials,etc.In addition,the challenges and opportunities including complexity of wastewaters,instability of H2 production,robust microorganisms,effect of membrane on two-chamber MEC,and integration of MEC with other treatment processes were deeply discussed.Except for the technical feasibility,both environmental feasibility and economic feasibility also need to meet social requirements.This review can indeed provide a basis for high-efficiency treatment and practical commercial applications of recalcitrant wastewaters via MECs in the future.

Temporal changes in the characteristics of algae in Dianchi Lake,Yunnan Province,China

Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restoration Act of China.Hydrothermal liquefaction allows a promising and direct conversion of algal biomass into biocrude oil.In this study,algal samples were collected from Dianchi Lake after a separation procedure including dissolved air flotation with polyaluminum chloride and centrifugation during four months,April,June,August and October.The algal biochemical components varied over the period;lipids from 0.7%to 2.1%ash-free dry weight(afdw),protein from 20.9%to 33.4%afdw and ash from 36.6%to 45.2%dry weight.The algae in June had the highest lipid and protein concentrations,leading to a maximum biocrude oil yield of 24.3%afdw.Biodiversity analysis using pyrosequencing revealed different distributions of microbial communities,specifically Microcystis in April(89.0%),June(63.7%)and August(84.0%),and Synechococcus in April(2.2%),June(12.0%)and August(1.0%).This study demonstrated remarkable temporal changes in the biochemical composition and biodiversity of algae harvested from Dianchi Lake and changes in biocrude oil production potential.