In this study, magnetic biochar (MAB) and humic acid (HA)-coated magnetic biochar produced from apple branches without and after cellulase hydrolysis (HMAB and CHMAB, respectively) were prepared and tested as adsorbents of enrofloxacin (ENR) and moxifloxacin (MFX) in aqueous solution. Compared with MAB and HMAB, novel adsorbent CHMAB possessed a superior mesoporous structure, greater graphitization degree and abundant functional groups. When antibiotic solutions ranged from 2 to 20 mg L⁻¹, the theoretical maximum adsorption capacities of CHMAB for ENR and MFX were 48.3 and 61.5 mg g⁻¹ at 35 °C with adsorbent dosage of 0.4 g L⁻¹, respectively, while those of MAB and HMAB were 39.6 and 54.4 mg g⁻¹, and 44.7 and 59.0 mg g⁻¹, respectively. The pseudo-second-order kinetic model and Langmuir model presented a better fitting to the spontaneous and endothermic adsorption process. The maximum adsorption capacity of ENR and MFX onto CHMAB was achieved at initial pH values of 5 and 8, respectively. Additionally, the adsorption capacity of ENR and MFX decreased with increasing concentrations of K⁺ and Ca²⁺ (0.02–0.1 mol L⁻¹). Synergism between the pore-filling effect, π-π electron-donor-acceptor interactions, regular and negative charge-assisted H-bonding, surface complexation, electrostatic interactions and hydrophobic interactions may dominate the adsorption process. This study demonstrated that a novel magnetic biochar composite prepared through pyrolysis of agricultural waste lignocellulose hydrolyzed by cellulase in combination with HA coating was a promising adsorbent for eliminating quinolone antibiotics from aqueous media.

Biomass burning tracers have been widely used to identify biomass burning types, but such tools can sometimes cause large uncertainties in the source attribution studies of PM₂.₅ (particles with an aerodynamic diameter of smaller than 2.5 μm). To quantify the relative importance of the major biomass burning tracers in PM₂.₅ released from biofuels combusted in the North China Plain, combustion experiments under the smoldering and flaming combustion conditions were conducted using nine types of typical household biofuels including two types of agricultural wastes, five types of hardwoods, one softwood, and one mixed wood briquette. PM₂.₅ samples were collected from the combustion experiments and source profiles of PM₂.₅ were thus determined for various biofuels under the two different combustion conditions. Carbonaceous species including organic carbon (OC) and elemental carbon (EC) were the major chemical components of the PM₂.₅ released from combustion of all the tested biofuels, with mass fractions of 37–45% and 4–7% under the smoldering condition and 11–25% and 7–29% under the flaming condition, respectively. Higher mass fractions of water-soluble inorganic ions (WSIIs, e.g., K⁺ and Cl⁻) in PM₂.₅ were observed under the flaming than smoldering combustion condition, while anhydrosugars (levoglucosan (LG) and mannosan (MN)) presented in an opposite pattern. The average LG/MN ratio in PM₂.₅ changed significantly with biofuel type (20–55 for agricultural wastes, 10–22 for hardwoods (except elm) and 3–6 for softwood), but varied little with combustion condition. In contrast, the K⁺/LG ratio in PM₂.₅ varied significantly between smoldering (<0.2) and flaming (>0.6) combustion conditions for all the biofuel types except softwood. Results from this study suggested that the ratio LG/MN was the best tracer for identifying the biofuel types and the ratio K⁺/LG is suitable for identifying the combustion conditions in this region.

The lotic habitats affected by trout farm waste are colonized with a particular invertebrate community of which chironomids are the most abundant group. However, there is little information available regarding how chironomid community structures respond to this type of pollution at the highest taxonomic resolution. Eight fish farms, together with their lotic systems as recipients, were used to test the variability of the chironomid community and its surrogates (taxonomic and functional metrics) across spatially arranged sampling sites to form a gradual decrease in the trout farm influence. The self organizing map (SOM) classified six different types of chironomid communities which were characteristic for both the control and affected habitats. The species indicator analyses listed 32 taxa as positive indicators of water pollution. The SOM and Kruskal-Wallis test revealed that the pattern of chironomid community structure obtained was mainly driven by six environmental parameters (Altitude, conductivity, distance from the outlet, hardness, HN₄-N, NO₃-N). Categorical principal components analysis (CATPCA) derived three models for each type of biotic metric, in which for diversity-, taxonomy- and functional feeding group-based metrics, the first two dimensions explained 55.2%, 58.3% and 55.4%, of the total variance respectively for 315 sampling sites. According to this analysis, the total number of taxa (S), abundance and the Shannon-Wiener index (H′) (as a diversity metric), as well as the proportion of Tanypodinae (as taxonomic group) and grazers/scraper (GRA) and gatherer collector (GAT)(as FFG metrics), were related to the outlet distance gradient, thus showing great potential to be used in the multimetric approach in bioassessment.

Soil contamination with antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) has becoming an emerging environmental problem. Moreover, the mixed pollutants' transfer and accumulation from soil to tuberous vegetables has posed a great threat against food security and human health. In this work, the application of two absorbing materials (maize biochar and sulfate modified eggshell) was able to reduce the poisonous effect of soil antibiotics on potato root system by stimulate the dissipation of water-soluble antibiotics in soil; and also improve food quality by increasing potato starch, protein, fat, and vitamins. Meanwhile, both amendments could effectively decrease the classes and the accumulative abundance of ARB and ARGs (sulI, sulII, catI, catII, ermA, ermB) in the edible parts of potato. The lowest abundance of ARGs was detected in the biochar application treatment, with the accumulative ARG level of 8.9 × 10² and 7.2 × 10² copies mL⁻¹ in potato peel (sull + catI + ermA) and tuberous root (sulI), respectively. It is the first study to demonstrate the feasibility of biochar and eggshell derived from agricultural wastes as green absorbing materials to reduce soil antibiotic, ARB, and ARGs accumulation risk in tuberous vegetable.

Anaerobic digestion, a promising technology for waste utilization and bioenergy generation, is a suitable approach to convert the shrimp waste to biomethane, reducing its environmental impact. In this study, shrimp chaff (SC) was co-digested corn straw (CS), wheat straw (WS), and sugarcane bagasse (SB). In co-digestion, SC enhanced biomethane production of CS by 8.47-fold, followed by SC + WS (5.67-folds), and SC + SB (3.37-folds). SC addition to agricultural biomass digestion also promoted the volatile solids removal up to 85%. Microbial community analysis of SC and CS co-digestion presented the dominance of phylum Bacteroidetes, Firmicutes, Proteobacteria, and Euryarchaeota. Proteolytic bacteria were dominant (18.02%) during co-digestion of SC and CS, with Proteiniphilum as major bacterial genera (14%) that converts complex proteinaceous substrates to organic acids. Among the archaeal community, Methanosarcina responsible for conversion of acetate and hydrogen to biomethane, increased up to 70.77% in SC and CS digestion. Addition of SC to the digestion of agricultural wastes can significantly improve the biomethane production along with its effective management to reduce environmental risks.

In China, more than 10,000 tons of bean-worm, which is rich in protein (68.5%) and essential amino acids (52.8%), is consumed annually. Thus, a large amount of bean-worm skin waste is generated, and is often indiscriminately disposed of, potentially causing environment problems. In this study, bean-worm skin (BWS) waste was pyrolyzed at 500 °C to produce biochar (BWS-BC), and the surface properties of BWS and BWS-BC were characterized using various spectroscopic techniques. Pb(II) adsorption properties of BWS and the corresponding biochar as a function of solution pH, contact time, and equilibrium concentration of Pb(II) were examined using adsorption isotherm, kinetics and thermodynamics studies. The maximum Pb(II) adsorption capacities based on the Langmuir isotherm model were calculated as 45 and 62 mg g⁻¹ for BWS and BWS-BC, respectively, which were comparable to the values obtained for biochars derived from other agro-wastes. The adsorption feasibility, favorability and spontaneity of Pb(II), as derived from the thermodynamic parameters, indicated that chemisorption and precipitation (e.g., hydroxypyromorphite) were the main adsorption mechanism in case of BWS and BWS-BC, respectively. Thus, conversion of BWS to biochar for Pb(II) adsorption can be considered as a feasible, promising and high value-added approach for BWS recycling.

Pollutants in wastewater and exhaust gas bring out serious concerns to public health and the environment. Biochar can be developed as a sustainable adsorbent originating from abundant bio-wastes, such as agricultural waste, forestry residue, food waste and human waste. Here we highlight the state-of-the-art research progress on pyrochar and hydrochar for the sorption of pollutants (heavy metal, organics, gas, etc) in wastewater and exhaust gases. The adsorption performance of pyrochar and hydrochar are compared and discussed in-depth, including preparation procedures (carbonization and activation), sorption possible mechanisms, and physiochemical properties. Challenges and perspective for designing efficient and environmental benign biochar-based adsorbents are finally addressed.

To meet human food and fiber needs in an environmentally and economically sustainable way, we must improve the efficiency of waste, water, and nutrient use by converting vast quantities of agricultural and food waste to renewable bioproducts. This work converts waste cherry pits, an abundant food waste in the Great Lakes region, to biochars and activated biochars via slow pyrolysis. Biochars produced have surface areas between 206 and 274 m²/g and increased bioavailability of Fe, K, Mg, Mn, and P. The biochars can be implemented as soil amendments to reduce nutrient run-off and serve as a valuable carbon sink (biochars contain 74–79% carbon), potentially mitigating harmful algal blooms in the Great Lakes. CO₂-activated biochars have surface areas of up to 629 m²/g and exhibit selective metal adsorption for the removal of metals from simulated contaminated drinking water, an environmental problem plaguing this region. Through sustainable waste-to-byproduct valorization we convert this waste food biomass into biochar for use as a soil amendment and into activated biochars to remove metals from drinking water, thus alleviating economic issues associated with cherry pit waste handling and reducing the environmental impact of the cherry processing industry.

In Dhaka, Bangladesh, fine particulate matter (PM₂.₅) air pollution shows strong seasonal trends, with significantly higher mean concentrations during winter than during the monsoon (winter = 178.1 μg/m³ vs. monsoon = 30.2 μg/m³). Large-scale open burning of post-harvest agricultural waste across the Indo-Gangetic Plain is a major source of PM₂.₅ air pollution in northern India during the non-monsoon period. This study evaluates the extent to which the seasonal differences in PM₂.₅ pollution concentrations in Dhaka are accounted for by biomass-burning vs. fossil-fuel combustion sources. To assess this, an index was developed based on elemental potassium (K) as a marker for biomass particulate matter, after adjusting for soil-associated K contributions. Alternatively, particulate sulfur was employed as a tracer index for fossil-fuel combustion PM₂.₅. By simultaneously regressing total PM₂.₅ on S and adjusted K, the PM₂.₅ mass for each day was apportioned into: 1) fossil-fuels combustion associated PM₂.₅; 2) biomass-burning associated PM₂.₅; and, 3) all other PM₂.₅. The results indicated that fossil-fuel combustion contributed 21.6% (19.5 μg/m³), while biomass contributed 40.2% (36.3 μg/m³) of overall average PM₂.₅ from September 2013 to December 2017. However, the mean source contributions varied by season: PM₂.₅ in Dhaka during the monsoon season was dominated by fossil-fuels sources (44.3%), whereas PM₂.₅ mass was dominated by biomass-burning (41.4%) during the remainder of the year. The contribution to PM₂.₅ and each of its source components by transport of pollution into Dhaka during non-monsoon time was also evaluated by: 1) Conditional bivariate (CBPF) and pollution rose plots; 2) Concentration weighted trajectories (CWT), and; 3) NASA satellite photos to identify aerosol loading and fire locations on high pollution days. The collective evidence indicates that, while the air pollution in Dhaka is contributed to by both local and transboundary sources, the highest pollution days were dominated by biomass-related PM₂.₅, during periods of crop-burning in the Indo-Gangetic Plain.

The active use of solid fossil fuels (coal) in the production of heat and electricity has led to significant pollution, climate change, environmental degradation, and an increase in morbidity and mortality. Many countries (in particular, European ones, China, Japan, the USA, Canada, etc.) have launched programs for using plant and agricultural raw materials to produce heat and electricity by burning them instead of or together with traditional fuels. It is a promising solution to produce slurry fuels, based on a mixture of coal processing, oil refining and agricultural waste. This paper presents the results of experimental research into the formation and assessment of the most hazardous emissions (sulfur and nitrogen oxides) from the combustion of promising coal slurry fuels with straw, sunflower and algae additives, i.e. the most common agricultural waste. A comparative analysis has been carried out to identify the differences in the concentrations of sulfur and nitrogen oxides from the combustion of typical coal, coal processing waste, as well as fuel slurries with and without plant additives. It has been shown that the concentration of sulfur and nitrogen oxides can be reduced by 62–87% and 12–57%, respectively, when using small masses of plant additives (no more than 10 wt%) and maintaining high combustion heat of the slurry fuel. However, the use of algae and straw in the slurry composition can increase the HCl emissions, which requires extra measures to fight corrosion. A generalizing criterion of slurry fuel vs. coal efficiency has been formulated to illustrate significant benefits of adding plant solid waste to coal-water slurries containing petrochemicals. Straw and sunflower waste (10 wt%) were found to be the best additives to reduce the air pollutant emissions.