Biomass Solid Waste Research Articles

Heterogeneous La and CeOx co-promoted SAPO-11 catalyst for catalytic upgrading of cellulose-derived volatile and methanol into hydrocarbon-rich fuels

In this paper, a series of La–Ce co-doped SAPO-11 catalysts with various La to Ce ratio were developed via wet impregnation method then employed in catalytic cellulose and methanol co-pyrolysis to produce hydrocarbon-rich biofuels. Comprehensive characterization technologies including X-ray diffraction, X-ray photoelectron spectroscopy, N2 physisorption, scanning electron microscope, transmission electron microscope, ammonia temperature-programmed desorption, Pyridine-infrared, and thermal gravimetric analyzer, were conducted to unveil the physicochemical properties, structure properties and acidity of as-prepared catalysts. Additionally the product content; aromatic selectivity and synergetic effect were also investigated. Additionally possible conversion pathway, deactivation mechanism and reusability were also deduced. La and Ce showed a certain synergetic effect and exhibited superior catalytic deoxygenation activity due to La–O and Ce-Ox species, suitable Brønsted acidity, abundant oxygen vacancies and enhanced mesopores structure, which was facilitated to promote the selectivity of hydrocarbon. Higher La content was fascinated to generate furans and ketones compounds, due to lower Brønsted acid site and smaller specific surface area. In contrast, higher CeOx content was beneficial to hydrocarbon formation via Diels-Alder reaction and dehydro-aromatization due to higher Brønsted acid site, total acidity, higher specific surface area, mesoporous pore volume as well as strong oxygen affinity of CeOx. The maximum proportion hydrocarbon, aromatics and minimum contents coke was obtained over 1La–1Ce/SAPO-11 were 77.96 %, 55.82 % and 9.81 %, respectively. Additionally, 1La–1Ce/SAPO-11 catalyst exhibited outstanding reusability and stability after four cycles; nearly ∼96 % relative content of hydrocarbon was maintained after regeneration test. Hence, the insight into the synergetic catalysis between La and CeOx species could provide a new potential possible pathway for design and synthesized efficient and eco-friendly bimetallic catalyst for selective catalytic deoxygenation organic solid waste biomass for valuable chemicals.

A comprehensive assessment of superabsorbent resin produced using modified quinoa husk and coal fly ash - Preparation, characterization and application

About 200 million tons of coal fly ash (CFA) is not effectively used in China every year. To enhance the utilization of biomass waste quinoa husk (QH) and solid waste CFA and reduce the preparation cost of superabsorbent resin (SAR), a low-cost, biodegradable modified quinoa husk-g-poly (acrylic acid)/coal fly ash superabsorbent resin (MQH-g-PAA/CFA SAR) was synthesized using modified quinoa husk (MQH), acrylic acid and CFA and used to improve the drought resistance and fertilizer conservation ability of soil. The surface morphology and performance of SAR were characterized by Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), which provided evidence for improving the properties of SAR by grafting MQH and adding CFA. In addition, the synthesis conditions were studied and optimized, together with the contents of initiator, crosslinker, MQH, and CFA to acrylic acid as well as the neutralization degree of acrylic acid. After optimization, the optimum water absorbency of SAR in deionized water, tap water, and physiological saline was 1302, 356, and 91 g/g respectively. The swelling and water-retention mechanisms of SARs were analyzed by a dynamic model and the results were in good agreement with the experimental data. In the soil experiment, the addition of SAR improved the drought resistance ability of soil, and reduced the leaching loss of fertilizer in the soil (from 49.5 % to 36.7 %). Therefore, this material exhibits significant potential in the field of agriculture and offers a novel approach with economic benefit for the utilization of MQH and CFA.

A Waste-to-Energy Technical Approach: Syngas–Biodiesel Blend for Power Generation

In this study, a technical analysis of synthesis gas (syngas) and biodiesel blend utilized in an internal combustion engine is presented. The experimental setup is composed of an engine workbench coupled with a downdraft gasifier which was fed with forest biomass and municipal solid waste at a blending ratio of 85:15, respectively. This research paper aims to contribute to the understanding of using fuel blends composed of synthesis gas and biodiesel, both obtained from residues produced in a municipality, since the waste-to-energy approach has been trending globally due to increasing waste generation allied with rising energy demand. The experiments’ controlling parameters regarding the engine are rotation and torque, exhaust gas temperature, and fuel consumption. The gasification parameters such as the oxidation and reduction temperatures, pressures at the filter, hood, and reactor, and the volume of tars and chars produced during the thermochemical process are also presented. Ultimate and proximate analyses of raw materials and fuels were performed, as well as the chromatography of produced syngas. The syngas produced from forest biomass and MSW co-gasification at a blending ratio in mass of 85:15 presented an LHV of around 6 MJ/m3 and 15% of H2 in volume. From the experiment using syngas and biodiesel blend in the engine, it is concluded that the specific consumption at lower loads was reduced by 20% when compared to the consumption of the same engine operating with regular diesel. The development of co-gasification of forest and municipal waste may then be an interesting technology for electrical energy decentralized generation.

Development of data-intensive techno-economic models for the assessment of a biomass, waste heat, and MSW integrated waste-to-electricity facility

This study develops a framework for an assessment of the integrated processing of various types of waste in a single waste-to-energy (W2E) facility. The FUNdamental ENgineering PrinciplEs-based model for Estimation of Cost of Energy from Biomass and Municipal Solid Waste (MSW) (FUNNEL-Cost-Bio-waste) was developed and used to assess the conversion of MSW, agricultural residue, forest residue, and waste heat to electricity via gasification. A geographic information systems (GIS)-based model was developed to estimate the availability of wastes at collection points and the transportation distances to the facility. A case study for Alberta (Canada) was conducted to assess the techno-economic feasibility of a 199 MW gasification-based facility. Depending on whether one or two waste heat sources are used for drying MSW, internal rates of return and the costs of generating electricity were estimated to be 11.18 % and 8.09 % and US $21.90/MWh and US $33.23/MWh, respectively. This information can be used for investment decision-making.

Maximizing Liquid Fuel Production from Reformed Biogas by Kinetic Studies and Optimization of Fischer–Tropsch Reactions

In the current work, the operating conditions for the Fischer–Tropsch process were optimized using experimental testing, kinetic modelling, simulation, and optimization. The experiments were carried out using a Ce-Co/SiO2 catalyst to examine how operating parameters affected the conversion of CO and product selectivity. A power-law kinetic model was used to represent the reaction rates in a mathematical model that was created to replicate the Fischer–Tropsch synthesis (FTS). It was decided to estimate the kinetic parameters using a genetic optimization technique. The developed model was validated for a range of operating conditions, including a temperature range of 200–240 °C, a pressure range of 5–25 bar, a H2/CO ratio of 0.5–4, and a space velocity range of 1000–5000 mL/gcat·h. The mean absolute relative error (MARE) between the experimental and predicted results was found to be 11.7%, indicating good agreement between the experimental data and the predicted results obtained by the mathematical model. Optimization was applied to maximize the production of liquid biofuels (C5+). The maximum C5+ selectivity was 91.66, achieved at an operating temperature of 200 °C, reactor total pressure of 6.29 bar, space velocity of 1529.58 mL/gcat·h, and a H2/CO feed ratio of 3.96. The practical implications of the present study are maximizing liquid biofuel production from biomass and municipal solid waste (MSW) as a renewable energy source to meet energy requirements, reducing greenhouse gas emissions, and waste management.

Thermogravimetric Assessment and Differential Thermal Analysis of Blended Fuels of Coal, Biomass and Oil Sludge

The coupled combustion of biomass and organic solid wastes including oil sludge has attracted much attention. Although the optimal mixing ratio of different coal types and biomass has been extensively studied, little attention has been paid to oil sludge that has undergone co-combustion. In this study, the combustion characteristics of blended fuel for coal, biomass and oil sludge under different mixing ratios are studied via a thermogravimetric test and differential thermal analysis. Kinetic analysis of tri-fuel is performed using the Flynn–Wall–Ozawa (FWO) and Dolye methods. The results show that the bituminous coal combustion process mainly involves the combustion of fixed carbon (236.0–382.0 °C). Wood pellet combustion (383.0–610.0 °C) has two processes involving the combustion of compound carbon and fixed carbon. Blending wood pellets effectively enhances combustion efficiency. Wood pellets from Korla (KOL) have the most obvious effect on reducing the ignition temperature. The blending combustion of bituminous coal (SC), wood pellets from Hutubi (HTB) and oil sludge (OS) have significant synergistic effects. As the OS mixing ratio increases from 10% to 20% with 45% HTB, Ti and Th decrease from 354.9 and 514.3 °C to 269.8 and 452.7 °C, respectively. In addition, f(α) is [−ln(1 − α)]2 for tri-fuel in most mixing ratios when α < 0.5, while f(α) becomes [−ln(1 − α)]3 at α > 0.5. At a high-HTB-level mixing ratio, increasing the OS content causes a decrease in activation energy to 35.87 kJ mol−1. The moderate blending of oil sludge improves the pre-finger factor and the combustion performance.

Effect of Alkaline Salts on Pyrolyzed Solid Wastes in Used Edible Oils: An Attenuated Total Reflectance Analysis of Surface Compounds as a Function of the Temperature

Biochars obtained via the pyrolysis of biomass are very attractive materials from the point of view of their applications and play key roles in the current energy context. The characterization of these carbonaceous materials is crucial to determine their field of application. In this work, the pyrolysis of a non-conventional biomass (solid wastes in used edible oils) was investigated. The obtained biochars were characterized using conventional techniques (TG, XRD, and SEM-EDX), and a deep analysis via ATR-FTIR was performed. This spectroscopic technique, which is a rapid and powerful tool that is well adapted to study carbon-based materials, was employed to determine the effect of temperature on the nature of functional groups on the surface. Moreover, the water washing of the raw sample (containing important quantities of inorganic salts) before pyrolysis evidenced that the inorganic salts act as catalysts in the biomass degradation and influence the degree of condensation (DOC) of PAH. Moreover, it was observed that these salts contribute to the retention of oxygenated compounds on the surface of the solid.

A Review on Advanced Processes of Biohydrogen Generation from Lignocellulosic Biomass with Special Emphasis on Thermochemical Conversion

The utilization of lignocellulosic biomass as an alternative energy source presents a promising opportunity to achieve a future energy system that is clean and free from CO2 emissions. To realize this potential, it is crucial to develop effective techniques for converting biomass and organic solid waste into secondary energy sources. Among the available options, hydrogen production stands out due to its numerous advantages, including its cleanliness, versatility in conversion and utilization technologies, high energy efficiency, and dense energy content per unit weight. This article offers a comprehensive overview of different conversion pathways and important technologies for generating hydrogen from biomass and organic solid waste. It specifically focuses on the thermochemical conversion process, which shows promise as an economically viable approach. While certain thermochemical conversion processes are still in the developmental phase, utilizing organic biomass for hydrogen production is widely recommended due to its ability to yield higher amounts of end products and its compatibility with existing facilities. However, it should be noted that this method necessitates a substantial amount of energy due to its endothermic nature. This article also explores alternative hydrogen conversion technologies and their potential for utilizing organic biomass as a feedstock, while addressing the challenges and limitations associated with these methods.

Sustainable production of aromatic-rich biofuel via catalytic co-pyrolysis of lignin and waste polyoxymethylene over commercial Al2O3 catalyst

Co-valorization of biomass and multiple solid wastes is essential to environment protection and energy security. Herein, aromatic-rich biofuel was produced from lignin and waste polyoxymethylene (POM) via catalytic co-pyrolysis process. Commercial and cheap γ-Al2O3 catalyst exhibited good catalytic performance. Series characterizations and bench-top pyrolysis experiments were conducted to illustrate the synergism between raw materials and the mechanism of aromatics formation. The TG analysis and thermodynamics calculation revealed that a remarkably positive synergistic effect existed between lignin and POM, which reduce the activation energies and make the reaction more conducive in terms of thermodynamics. Meanwhile, the yields of biochar and bio-oil increased considerably. Additionally, the operating conditions affected the product distributions significantly. The suitable mixing ratio of lignin to POM was around equal (5:5) with the bio-oil yield increased to 28.3 % and aromatic hydrocarbons selectivity increased to > 95 %. Moreover, POM, the precursor for alkylating reagents and hydrogen donors, could promote the deoxygenation reactions of phenolic intermediates and result into aromatic hydrocarbons. The acid sites of γ-Al2O3 promoted series secondary cracking reactions (alkylation, deoxygenation), and thus improved bio-oil quality. Finally, the stability test showed that commercial γ-Al2O3 catalyst was slightly deactivated after 4 cycles because of coke deposits and acid sites loss.

A novel biomass solid waste-based form-stable phase change materials for thermal energy storage

To improve the energy storage capacity of phase change materials, the influence of plant ash, a typical biomass solid waste, with different particle sizes on the encapsulation of palmitic acid has been investigated to find better supporting materials for preparing form-stable phase change material (FSPCM). During the experiment, palmitic acid/Plant ash composites with different mass fractions of palmitic acid were fabricated by the direct impregnation method. And the packaging capability, particle size distribution, surface area, microstructure, chemical compatibility, and thermal properties were investigated systematically. The particle size distribution test shows that the mean-volume diameter of plant ash sieved by 30–60 mesh (PLA-1) and PLA sieved by −60 mesh (PLA-2) is 60.21 and 41.21 μm, respectively. The DSC results show that the enthalpy of PA/PLA-2 FSPCM is 99.7 J/g, which is almost twice that of PA/PLA-1 FSPCM. In short, as-prepared PA/PLA FSPCM exerts a bigger energy storage capacity, which makes it a great candidate for thermal energy storage.

Adsorptive Removal of Dye (Methylene Blue) Organic Pollutant from Water by Pine Tree Leaf Biomass Adsorbent

In this laboratory batch adsorption study, the raw pine tree leaf biomass solid waste adsorbent material was used for the removal of methylene blue (MB) dye from water at different physicochemical process conditions. The characteristics of adsorbents were determined for particle size, surface area, the existence of functional group identification, and the morphology of the adsorbent surface. The adsorption was performed at different process conditions, which include solution pH, dye concentrations, adsorbent doses, and temperature, respectively. In this study, it was found that MB dye adsorption increased with increases in solution pH and adsorbate MB dye concentration but decreased with adsorbent doses and temperature at fixed process conditions. The Langmuir isotherm model was best fitted with the experimental equilibrium data, with a higher linear regression coefficient (R2) value of 99.9% among the two widely used Langmuir and Freundlich adsorption isotherm model equations. The maximum Langmuir monolayer adsorption capacity of raw pine leaf was found to be 36.88 mg/g, which was comparable with other reported adsorbent capacities towards methylene blue (MB) dye adsorption. The value of the separation factor, RL, from the Langmuir isotherm model equation gives an indication of favorable adsorption. Thermodynamic parameters such as standard Gibbs free energy change (ΔG0), standard enthalpy change (ΔH0), and standard entropy change (ΔS0) indicated that the methylene blue (MB) dye adsorption by pine tree leaf biomass was spontaneous and exothermic in nature and that the mechanism of adsorption was mainly physical adsorption. Finally, limitations and future studies are also discussed here. The outcome of this batch adsorption study may result in the valorization of locally available large pine tree leaf residue waste, which could be used in water purification.

Characterization of solid waste biomass of agar processing plants and scale-up production of bioethanol

Characterization of solid waste biomass of agar processing plants and scale-up production of bioethanol

Green utilization of biomass by-product poplar leaf ash: A novel eco-friendly cementitious material for cement mortar replacement

The use of biomass for power generation is increasing. However, solving the solid biomass waste generated during the combustion process is a challenge. In order to reduce costs and the use of forestry waste, the replacement of cement in cement mortars with the same quality of poplar leaf ash was studied. The present study documents the potential of biomass ash obtained from calcined leaf ash as a supplementary cementitious. By thermogravimetric tests, 20 °C, 310 °C, 470 °C, and 650 °C were selected as the calcination temperatures. The effects of biomass ash on uniaxial compressive strength, crack extension, acoustic emission, and the microstructure of specimens at different curing ages of 7 d and 28 d were investigated. The results show that the strength of specimens mixed with 20 wt% poplar leaf ash is about 60% of cement mortar. The porosity of cement mortar specimens with biomass ash is higher than that of cement mortar. The hydration products of C-S-H and AFt are slightly less than cement mortar. To achieve the same flowability, the water-binder ratio is higher when mixed with biomass ash. As a result, the biomass ash specimens have higher porosity and lower strength. The strength of 310 °C and 470 °C is approximately 8.41% and 4.70% lower than that of 650 °C. The optimum calcination temperature for the pozzolanic activity of poplar leaf biomass ash is 650 ℃. This promotes the efficient use of biomass solid waste and the construction industry is green development.

Costs of Gasification Technologies for Energy and Fuel Production: Overview, Analysis, and Numerical Estimation

During recent years, gasification technology has gained a high potential and attractiveness to convert biomass and other solid wastes into a valuable syngas for energy production or synthesis of new biofuels. The implementation of real gasification facilities implies a good insight of all expenses that are involved, namely investments required in equipment during the project and construction phases (capital expenditures, CapEx) and costs linked to the operation of the plant, or periodic maintenance interventions (operational expenditures, OpEx) or costs related to operations required for an efficient and sustainable performance of a gasification plant (e.g., feedstock pre-treatment and management of by-products). Knowledge of these economic parameters and their corresponding trends over time may help decision-makers to make adequate choices regarding the eligible technologies and to perform comparisons with other conventional scenarios. The present work aims to provide an overview on CapEx associated with gasification technologies devoted to convert biomass or solid waste sources, with a view of reducing the carbon footprint during energy generation or production of new energy carriers. In addition, an analysis of technology cost trends over time using regression methods is also presented, as well as an evaluation of specific capital investments according to the amount of output products generated for different gasification facilities. The novelty of this work is focused on an analysis of CapEx of existing gasification technologies to obtain distinct products (energy and fuels), and to determine mathematical correlations relating technology costs with time and product output. For these purposes, a survey of data and categorization of gasification plants based on the final products was made, and mathematical regression methods were used to obtain the correlations, with a statistical analysis (coefficient of determination) for validation. Specific investments on liquid biofuel production plants exhibited the highest decreasing trend over time, while electricity production became the least attractive solution. Linear correlations of specific investment versus time fitted better for electricity production plants (R2 = 0.67), while those relating the product output were better for liquid biofuel plants through exponential regressions (R2 = 0.65).

Alkaline gases emission estimation and paraconsistent logic techniques application to label bagasse combustion conditions

When some renewable energy sources are used, such as biomass solid waste, it is necessary to measure and control pollutant emissions. Since raw sugarcane comes from a wide variety of supply sources, it is necessary to monitor the behavior of the biomass residues during the burning process to control flame stability, emissions, and combustion efficiency. The variation in the combustion temperature of biomass affects the combustion efficiency and also the emission of alkaline metals, such as potassium (K) and sodium (Na), which can cause corrosion in boilers. The objective of the present work is to estimate the content of alkali gases in the flames during the burning of solid biomass residues, specifically sugarcane bagasse in this case. The flame emission spectroscopy (FES) spectrometry technique is used and flame emission spectra is captured during the combustion of bagasse in a pilot furnace. The flame temperature is calculated using the two-color method together with the inverse Levenberg-Marquard method. Models and correlations from literature are used to obtain a database of emission content of sodium and potassium. Using paraconsistent logic techniques, a predictor algorithm is implemented and bagasse samples were labeled to identify similar physical combustion conditions. The results of the emission of sodium and potassium estimated for groups labeled using the algorithm of paraconsistent logic are compared and show good agreement between them. A good and reasonable agreement was found in the estimation of the emission content of potassium and sodium.

Phosphate and ammonia nitrogen recovery from sewage sludge supernatants by coupled MgO-biomass ash and its potential as heavy metal adsorbent

Aiming at the problem of complex treatment for energy solid waste—biomass ash (BA) from thermal power plant and difficult recovery for phosphorus and ammonia nitrogen in sewage sludge supernatants, a coupled MgO-biomass ash (CMBA) was established. CMBA composites were synthesized by in situ thermal-precipitation modification method, which simultaneously achieved recovery of phosphorus and ammonia nitrogen and BA resource utilization, and explored the potential of recovered CMBA (RCMBA) containing phosphate and ammonia nitrogen to remove heavy metal from wastewater. The results showed that magnesium oxide could be effectively loaded on the surface of BA at an MgCl2 concentration of 1.25 M and calcination temperature of 400 °C. pH, adsorbent dosages and initial concentration affected the adsorption capacity of phosphate and ammonia nitrogen by 400CMBA. The existence of K+, Ca2+ and Mg2+ ions promoted the removal of phosphate by 400CMBA, but hindered the removal of ammonia nitrogen. The existence of Cl-, NO2- and SO42- ions affected the removal of phosphate by 400CMBA. The adsorption processes of 400CMBA for phosphate and ammonia nitrogen can be used with the Langmuir-Freundlich model and the pseudo-second-order model reaching a maximum adsorption capacity of 262.88 mg/g and 122.39 mg/g, respectively. The adsorption behavior was controlled by several processes, spontaneous and thermogenic chemisorption. The saturated adsorbent can be effectively regenerated in 0.1 M HCl solution. After the fifth regeneration, the phosphate and ammonia nitrogen removal rates were less than 50% and 25%, respectively. The adsorption mechanisms of phosphate and ammonia nitrogen by 400CMBA were mainly physical adsorption, electrostatic attraction, ion exchange, complexation reaction and chemical precipitation, among which chemical precipitation was dominated by struvite crystallization was dominant. In addition, RCMBA had a specific removal effect on heavy metal in solutions. Overall, this work provides a feasible way for the resource utilization of energy solid waste-BA from thermal power plant.

Techno‐economic and policy analysis of hydrogen and gasoline production from forest biomass, agricultural residues and municipal solid waste in California

AbstractTechno‐economic and policy analyses were performed of hydrogen and gasoline production from forest biomass (FB). They were compared with fuels produced using agricultural residues and municipal solid waste in California. Twelve process designs were analyzed, with and without carbon capture and storage, and life‐cycle analysis was performed, using California's Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) 3.0 model, to calculate the average life‐cycle carbon intensity of different process designs for hydrogen and gasoline. Discounted cash flow models were developed to assess profitability in terms of the net present value and internal rate of return (IRR). The results showed that forest‐to‐fuel pathways (positive IRR between 2%−16%) were the least competitive biomass‐based pathway option. Sensitivity analysis was performed on economic parameters including feedstock price and renewable identification number (RIN) credit price. In the case of RIN credits, profitability declined significantly as the proportion of FB from federal lands increased given existing statutory limitations. Given the importance of increasing forest management to reduce wildfire risks, the necessary additional policy incentives were quantified to equalize the cost of forest‐to‐fuels pathways with the other biofuels pathways. To ensure FB‐to‐fuels pathways are cost competitive with agricultural residues, policymakers could increase the low carbon fuel standard (LCFS) credit price for forest fuels (additional credit price support of $41–75 t/CO2e), give additional credit to lifecycle emissions reductions from forest fuels (additional carbon intensity decrease of 19–76 gCO2e MJ−1), provide concessionary debt or equity with a target weighted average cost of capital (WACC) = 3–4%, subsidize capital costs (12–22% of costs), or subsidize FB delivery ($35–66 per dry ton delivered).

From the conventional to the intermittent biodrying of orange solid waste biomass

Biodrying is an innovative solution in the search for ecologically viable and economically attractive drying processes. However, biodrying processes often have long operating times, which makes them unsuitable for some applications. Thus, the objective of this work was to evaluate the biodrying of orange solid waste biomass in three operation modes: conventional full load and long operation time (CFLT); conventional partial load and short operating time (CPST); and intermittent partial load biodrying with homogenization (IPST). The results showed that the oxidative biological activity promoted temperature peaks greater than 50 °C for the CFLT operation, and 45 °C for the CPST and IPST operations. Both, CFLT and CPST, presented irregular distribution of the gaseous phase in the bed and poor water removal. The IPST operation, however, promoted a significant improvement in the moisture transport mechanisms. Comparatively, orange solid waste with an initial moisture of (3.0 ± 0.1) db. had an average final moisture of (2.5 ± 0.1) db. for CFLT (t = 500 h), (2.2 ± 0.1) db. for CPST (t = 48 h), and (1.6 ± 0.1) db. for IPST (t = 48 h). We concluded that the IPST operation is advantageous over CFLT and CPST, presenting higher moisture reduction with a significant reduction in operating time from 500 h to 48h

Conversion of corn shell as biomass solid waste into carbon species for efficient decontamination of wastewater via heavy metals adsorption

Biomass-based solid residuals can be of serious hazardous environmental impacts if left for natural degradation. Thus, the proper utilization of such residuals is highly recommended. Therefore, one of solid residuals: namely, corn shell, was used in this study to synthesize carbon species (labeled as CS-C) as an adsorbent for efficient removal of heavy metal ions from aqueous solution. The structural properties and the textural characteristics of the prepared carbon species were verified. The present charges on the carbon surface were acquired via zeta potential analysis. The performance of CS-C, as adsorbent, was investigated through batch technique. Adsorption isotherm was optimally described using the Langmuir model reflecting that the removal process occurs at the homogenous surface of CS-C through a chemical reaction (surface complexation mechanism). The equilibrium state for the sorption process was reached after 4 h of interaction. The kinetic studies revealed the nice fit of heavy metal removal process to Pseudo-second-order model and the thermodynamics is matched to endothermic, spontaneous, and feasible sorption process. The displayed results could emphasize the high potentiality of CS-C to act as a remarkable sorbent for efficient tackling of water contaminants.

Synthesis of hierarchically porous carbon materials by zinc salts-assisted carbonization of biomass and organic solid wastes

Hierarchically porous carbons (HPCs) with multimodal pores have attracted considerable attention due to their unique physical and chemical properties and various application potentials in heterogeneous catalysis, environmental treatment, and energy storage and conversion. Herein, we report a general and simple zinc salts-assisted method for the synthesis of HPCs with varied porosity and chemical functionalities by the direct carbonization of diverse biomass and wastes. During the carbonization, zinc salts are thermally decomposed into nanoparticles that serve as in-situ templates to introduce nanopores in carbons. The prepared HPCs exhibit high specific surface areas (up to 2432 m2 g−1), large pore volumes (up to 4.30 cm3 g−1), and broad pore size distributions. Moreover, the zinc salts can be recovered and recycled, supporting the sustainable production of HPCs on large scale. The prepared HPCs-supported catalysts with atomically dispersed metal sites exhibit promising electrocatalytic performance for the oxygen reduction reaction.