Interactions of beet leafhopper (Hemiptera: Cicadellidae), vector of beet curly top virus, and hemp in New Mexico.

The beet leafhopper, Circulifer tenellus (Baker 1896), is the sole vector of beet curly top virus (BCTV). Both the virus and the vector have very wide host ranges, including many crops and weeds. Industrial hemp (Cannabis sativa L.) has been reported as a host for both the virus and leafhopper in the past few years with the legal cultivation of the crop in the United States. This research assessed the interactions of the beet leafhopper and hemp in New Mexico by determining the natural infection of hemp with BCTV in 3 field plots in 2021 and 2022 and monitoring the numbers of leafhoppers using yellow sticky traps. The relative preference of beet leafhopper for hemp types and varieties of hemp was assessed using cafeteria-style choice tests. Higher numbers of beet leafhoppers were trapped in and around hemp fields in 2022 than in 2021 in all 3 locations. BCTV was found to infect all 3 types of hemp (cannabidiol or CBD, fiber, and grain) in 2022 in 1 location and only a single CBD variety of hemp in the other 2 locations. Two BCTV strains were identified in CBD hemp, while an additional BCTV strain was found infecting chile pepper grown at the same location.

Waste-to-wealth application of wastewater treatment algae-derived hydrochar for Pb(II) adsorption.

Hydrochar, as an energy-lean solid waste, is generated from an advanced biofuel conversion technique hydrothermal liquefaction (HTL) and always leads to environmental pollution without appropriate disposal. In this study, HTL-derived hydrochar is recycled and prepared as adsorbent used for Pb(Ⅱ) removal from wastewater. As the original porous structure of hydrochar is masked by oily volatiles remained after HTL, two types of oil-removal pretreatment (Soxhlet extraction and CO2 activation) are explored. The result shows that CO2 activation significantly enhances the adsorption capacity of Pb(Ⅱ), and the maximum adsorption capacity is 12.88 mg g-1, as evaluated using Langmuir adsorption model. Further, apart from oily volatiles, most inorganic compounds derived from wastewater-grown algae is enriched in hydrochar, causing a smaller surface area of hydrochar. An ash-removal alkali treatment following CO2 activation is introduced to dramatically increase the adsorption capacity to 25.00 mg g-1 with an extremely low Pb(II) equilibrium concentration of 5.1×10-4 mg L-1, which is much lower than the maximum level of Pb concentration in drinking water (set by World Health Organization). This work introduces an approach to reuse HTL-hydrochar as an inexpensive adsorbent in Pb-contaminated water treatment, which not only provides another possible renewable adsorbent candidate applied in the field of lead adsorption, but also finds an alternative route to reduce solid waste effluent from HTL process.

Characterization of resin extracted from guayule (Parthenium argentatum): A dataset including GC-MS and FT-ICR MS.

Guayule (Parthenium argentatum), a shrub native to the arid region of the U.S. southwest and Mexico belonging to the Asteraceae family, is a source of high quality, hypoallergenic natural rubber with applications in pharmaceutical, tire, and food industries. Production of rubber results in a substantial amount of resin-containing residues which contain a wide variety of secondary metabolites (sesquiterpene esters, triterpene alcohols, fatty acids, etc.). In order to enhance the economic viability of guayule as an industrial crop, value-added use of the residues is needed and has the potential to reduce gross rubber production costs. The main objective of this research is the characterization of guayule resin using rapid and accurate analytical techniques to identify compounds of potential commercial value. Guayule resin is inherently complex and includes many high-molecular-weight and non-volatile compounds that are not easy to observe using traditional chromatographic techniques. The combination of two mass spectroscopy techniques: gas chromatography mass spectroscopy (GC-MS) and high-resolution Fourier transform ion cyclotron resonance mass spectroscopy (FT-ICR MS), were used to characterize the composition of the extracted resin from guayule (Parthenium argentatum). FT-ICR MS was used to characterize hundreds of compounds with over a wide range of molecular weights and degrees of aromaticity at higher levels of mass accuracy than other forms of mass spectrometry. GC-MS was used to identify volatile compounds like mono- and sesquiterpene compounds.

Roles of Co-solvents in hydrothermal liquefaction of low-lipid, high-protein algae.

Valorization of algal biomass is often limited by its low lipid content. Here, different alcohols: ethanol, isopropanol, and glycerol, were studied as co-solvents to improve the conversion efficiency of a lipid-poor microalgae, Galdieria sulphuraria, by hydrothermal liquefaction. Bio-crude oil yield increases, from 13 to 73 wt% (on dry algae basis), were attributed to the alcohols facilitating the transfer of algal protein-derived fragments from the aqueous phase into the oil phase. A series of characterization results showed that bio-crude oil formation was mainly the result of alcohols reacting with algal fragments via Maillard reactions, alkylation, and esterification, respectively. Insights into the synergistic effect of low-lipid feed and alcohol provide mechanistic support for choosing an alcohol-rich waste, crude glycerol, to improve bio-crude oil production from HTL of wastewater-grown G. sulphuraria. Promising improvements in yield and energy recovery indicates competitive economics for a low-lipid biomass waste-to-biofuel conversion technique.

Modification of a pilot-scale continuous flow reactor for hydrothermal liquefaction of wet biomass.

A pilot-scale continuous flow reactor (CFR) was modified for hydrothermal liquefaction (HTL) of algae slurry under subcritical conditions to investigate the feasibility of scaling up from batch to continuous processing. Modifications included a novel dual filter system that can remove solids at system pressure and temperature, and undergo in-situ cleaning. Commissioning was carried out to address potential particle settling and clogging problems, and to estimate reactor transport characteristics. CFR performance was evaluated by running 31.4 L algae slurry with solids loadings of 3-5 wt.% under 325-350 °C and 18 MPa for 7 h. C and N elemental yields in HTL aqueous phase reached 39.0 wt.% and 61.8 wt.%, respectively. Future improvements to the CFR system will focus on higher solids loading and addition of in-line HTL liquid upgrading capabilities following the filtration system. •A high-temperature, high-pressure filtration system was designed to remove solids from HTL liquid/gaseous products at near reaction conditions to keep heavy oils in the liquid phase.•Uninterrupted reactor operation was achieved by cycling between the dual filter systems and performing in-situ filter cleaning.•Measured reactor residence time distributions were narrow and close to the calculated theoretical mean time.

Bio-crude oil from hydrothermal liquefaction of wastewater microalgae in a pilot-scale continuous flow reactor.

To explore the feasibility of scaling up hydrothermal liquefaction (HTL) of algal biomass, a pilot-scale continuous flow reactor (CFR) was operated to produce bio-crude oil from algal biomass cultivated in urban wastewater. The CFR system ran algal slurry (5 wt.% solids loading) at 350 °C and 17 MPa for 4 h without any clogging issues. Bio-crude oil chemistry was characterized by high-resolution Fourier transform mass spectroscopy (FT-MS), proton nuclear magnetic resonance spectroscopy (1H NMR), bomb calorimetry, and elemental analysis. Bio-crude oil yield of 28.1 wt% was obtained with higher heating values of 38-39 MJ/kg. The quality of light bio-crude oil produced from the CFR system was comparable in terms of molecular structures to bio-crude oil produced in a batch reactor.

Hydrothermal liquefaction of Galdieria sulphuraria grown on municipal wastewater.

Two strains of Galdieria sulphuraria algae, 5587.1 and SOOS, were grown on municipal wastewater to develop energy-positive treatment systems. Hydrothermal liquefaction (HTL) of 5-10 wt% algal biomass solids was conducted at 310-350 °C for 5-60 min to produce bio-crude oil. HTL product yields and energy recovery were compared to those from previous studies using G. sulphuraria grown on a modified Cyanidium medium. Total bio-crude oil yields were lower (11.2-23.0 wt%) and char yields were higher (22.6-36.4 wt%) for HTL of algae grown on actual wastewater compared with that grown on media (31.4 wt% and 4.8 wt%, respectively), indicating a potential limitation for using yields from media-based studies. High-resolution mass spectroscopy of bio-crude oil provides new insights into differences in composition based on growth media. Energy recovery in total bio-crude oil and char at 350 °C was 17-28% and 14-19%, respectively, for the 5587.1 strain, and 23-27% and 14-25%, respectively, for the SOOS strain.

Short-term leachability of salts from Atriplex-derived biochars.

Disposal of concentrate from brackish water desalination is limited by concerns of salt leaching into fresh water sources. Prevention of salt from leaching can greatly increase desalination concentrate management costs, as there are few options to recover those costs. An option for concentrate disposal is to grow halophyte crops using the concentrate as irrigation water. The purpose of this study was to determine how much of the Ca, Mg, Na, and K taken up by Atriplex species during growth can be stabilized by pyrolysis, thus preventing those cations from returning into the soil solution after harvest. Results show that salts in the biomass are concentrated into the biochars and that pyrolysis conditions affect the amount of salt that can be leached with water. Ca was the most retained of the cations: 100% and 94% were retained in A. canescens biochars and A. lentiformis 600 °C biochar, respectively. Mg retention was similar: 100% and 93% retained for A. canescens and A. lentiformis 600 °C biochars, respectively. Increasing pyrolysis temperature increased the retention of Ca and Mg; trends for K and Na were inconsistent. Soil application of these biochars will still be problematic due to low retention of Na against short-term leaching, thus limiting the potential for on-site sequestration to enable land utilization for crop production. With more understanding of the salt formation and retention mechanisms within biomass, higher amounts of salt might be sequestered longer, while taking advantage of the carbon sequestration and soil quality benefits of biochars.

Hydrothermal liquefaction of high- and low-lipid algae: Mass and energy balances.

Hydrothermal liquefaction (HTL) of high-lipid microalgae Nannochloropsis salina (N. salina) and low-lipid microalgae Galdieria sulphuraria (G. sulphuraria) were run under subcritical conditions (310-350 °C and 10-17 MPa) in a 1.8 L batch autoclave system. HTL mass and energy balances for both species were compared under different operating conditions to predict the optimum reaction conditions for new algae strains based on their feedstock composition. Bio-crude oils and chars were characterized by bomb calorimetry, elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA). Under the optimized conditions, 59 wt% and 31 wt% bio-crude oil yields were obtained from HTL of N. salina and G. sulphuraria, while 85% and 59% of the feedstock energy were partitioned into N. salina-derived and G. sulphuraria-derived bio-crude oils, respectively. More favorable energy balances were related to shorter reaction times and higher algal solid contents.

Ex-situ catalytic pyrolysis of wastewater sewage sludge - A micro-pyrolysis study.

Concerns over increasing amounts of sewage sludge and unsustainability of current disposal methods have led to development of alternative routes for sludge management. The large amount of organics in sewage sludge makes it potential feedstock for energy or fuel production via thermochemical pathways. In this study, ex-situ catalytic pyrolysis using HZSM-5 catalyst was explored for the production of olefinic and aromatic hydrocarbons and nutrient-rich char from sewage sludge. The optimal pyrolysis and catalysis temperatures were found to be 500°C and 600°C, respectively. Carbon yields of hydrocarbons from sewage sludge were higher than for lignocellulose; yield differences were attributed to the high extractives content in the sludge. Full recovery of most inorganic elements were found in the char, which suggests that catalyst deactivation maybe alleviated through ex-situ catalytic pyrolysis. Most of the nitrogen was retained in the char while 31.80% was released as ammonia, which suggests a potential for nitrogen recycling.

Extent of pyrolysis impacts on fast pyrolysis biochar properties.

A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization.