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Waste management is an increasing global concern due to the rise in urbanization and industrialization. This study examines the co-pyrolysis of date pits (DP) and single-use plastics (polypropylene-PP and Styrofoam-PS) as a way to create value-added products. Single, binary, and ternary mixtures were pyrolyzed at three different heating rates to understand the synergy, kinetics, and thermodynamics. The results showed positive synergy and reduced activation energies during co-pyrolysis, due to varying reaction mechanisms. The positive values of ∆H, ∆G, and negative ΔS indicate endothermic non-spontaneous reactions and disorder in the products instead of the reactants during pyrolysis. Future studies should explore upscaling this process for sustainable energy production. [ABSTRACT FROM AUTHOR]

Traditional bulk adsorbents, employed for the removal of dyes and metal ions, often face the drawback of requiring an additional filtration system to separate the filtrate from the adsorbent. In this study, we address this limitation by embedding the adsorbent into the polymer matrix through a process involving dissolution–dispersion, spin-casting, and heat-stretching. Selective dissolution and dispersion facilitate the integration of the adsorbent into the polymer matrix. Meanwhile, spin-casting ensures the formation of a uniform and thin film structure, whereas heat-induced stretching produces a porous matrix with a reduced water contact angle. The adsorbent selectively captures dye molecules, while the porous structure contributes to water permeability. We utilized inexpensive and readily available materials, such as waste polyethylene and calcium carbonate, to fabricate membranes for the removal of methylene blue dye. The effects of various parameters, such as polymer-adsorbent ratio, initial dye concentration, and annealing temperature, were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. The equilibrium data were best represented by the Langmuir isotherm, with maximum adsorption capacity of 35 mg/g and 43 mg/g at 25 °C and 45 °C, respectively. The membranes can be regenerated and recycled with a 97% dye removal efficiency. The study aims to present a template for adsorbent-embedded polymeric membranes for dye removal, in which adsorbent can be tailored to enhance adsorption capacity and efficiency. [ABSTRACT FROM AUTHOR]

One of the primary sources of waste in Qatar is animal waste, which includes poultry litter. Annually, Qatar produces approximately 0.83 x 106 t of poultry litter. Consequently, there is a need for a more sustainable waste treatment approach to handle it. Hence, this study's principal objective is to investigate the suitability of poultry litter as a feedstock for pyrolysis, with a specific emphasis on its potential for biochar generation. The physicochemical evaluations of poultry litter were performed. The potential for biochar formation from poultry litter was assessed using empirical equations at two different pyrolysis temperatures, namely 250 °C and 500 °C. Additionally, an economic analysis was conducted in order to ascertain the potential revenue generated by biochar derived from poultry litter. The composition of poultry litter, characterised by a moderate volatile content of 60 % and a fixed carbon content of 16 %, along with a moderate higher heating value (HHV) of 16 MJ/kg, indicates its potential suitability as a highly suitable feedstock material for biochar generation through pyrolysis. According to the findings of the technical analysis, biochar yields of up to 50 % and 31 % can potentially be achieved at 250 °C and 500 °C, respectively. Moreover, the findings of the study indicate that Qatar has the capacity to generate up to 0.35 x 106 t of biochar annually from its poultry litter. Additionally, the economic analysis suggests that the country can generate annual revenue of about 69 x 106 USD from the selling of biochar. [ABSTRACT FROM AUTHOR]

Green walls and roofs are sustainable building systems with several benefits. However, the irrigation requirements of these building systems conflict with water sustainability goals in water-scarce places. This study investigates using greywater directly to irrigate ornamental species for such situations by examining the effects of freshwater and greywater irrigation on Ruellia tuberosa growth, plant health and soil characteristics. Five replicates for each condition were grown for 91 days. Greywater irrigation led to a 15% higher plant growth height, a 31% higher plant biomass (p = 0.065), and a 71% increase in stem biomass (p < 0.001) compared to freshwater irrigation. However, greywater-irrigated plants had reduced chlorophyll content (10.7%, p < 0.001), and increased leaf chlorosis (p = 0.003), likely caused by stress from laundry and detergent chemicals. Greywater irrigation led to greater mineral content in greywater-irrigated plant biomass and soil for all minerals tested, most notably boron, which was deficient in the soil. Greywater-irrigated soil also had a higher organic content according to FTIR and electron dispersive spectroscopy. Greywater irrigation improved nutritional and soil conditions, including phosphate, which helped Ruellia tuberosa flourish. This study suggests raw greywater can replace freshwater in water-scarce climates for green wall irrigation instead of high-energy onsite greywater treatment systems. [ABSTRACT FROM AUTHOR]

Global waste production is significantly rising with the increase in population. Efforts are being made to utilize waste in meaningful ways and increase its economic value. This research makes one such effort by utilizing gas-to-liquid (GTL)-derived biosolids, a significant waste produced from the wastewater treatment process. To understand the surface properties, the biosolid waste (BS) that is activated directly using potassium carbonate, labelled as KBS, has been characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and Brunauer–Emmett–Teller (BET). The characterization shows that the surface area of BS increased from 0.010 to 156 m2/g upon activation. The EDS and XPS results show an increase in the metal content after activation (especially iron); additionally, XRD revealed the presence of magnetite and potassium iron oxide upon activation. Furthermore, the magnetic field was recorded to be 0.1 mT using a tesla meter. The magnetic properties present in the activated carbon show potential for pollutant removal. Adsorption studies of methylene blue using KBS show a maximum adsorption capacity of 59.27 mg/g; the adsorption process is rapid and reaches equilibrium after 9 h. Modelling using seven different isotherm and kinetic models reveals the best fit for the Langmuir-Freundlich and Diffusion-chemisorptionmodels, respectively. Additional thermodynamic calculations conclude the adsorption system to be exothermic, spontaneous, and favoring physisorption. [ABSTRACT FROM AUTHOR]

This study aims to understand the potential of using biosolids produced from the world's largest gas-to-liquid (GTL) plant for water treatment applications. The metal fractionization of the two samples: raw biosolid (BS) and the pyrolyzed biosolid-BS char (BSC) (temperature: 450 °C, heating rate: 5 °C/min, residence time: 30 min) into exchangeables (F1), reducible (F2), oxidizable (F3), and residual (F4) were carried out following the Community Bureau of Reference (BCR) procedure. Characterization showed an increased carbon content and reduced oxygen content in the biochar sample. Additionally, the presence of calcium, magnesium, and iron were detected in smaller quantities in both samples. Based on the extraction results for metals, the environmental risk analysis was determined based on RAC (Risk Assessment Code) and PERI (Potential Ecological Risk Index) indices. Furthermore, leaching studies following the TCLP (Toxicity Characteristic Leaching Procedure) were conducted. The results prove that pyrolyzing stabilizes the metals present in the raw material as BS sample had high F1 fractions, and the BS char had a greater F4 fraction. While the RAC and PERI indices show that the pyrolyzed BS has a 'low risk', much reduced compared to the original BS sample, this is confirmed by the leaching studies that displayed minimal leaching from the pyrolyzed sample. Overall, this study proves that the GTL biosolids can best be applied for water treatment after pyrolysis. [ABSTRACT FROM AUTHOR]

Cucumber waste from the greenhouse is a nutrient and high cellulose-rich biomass that could potentially be used to produce biochar as a valuable resource. Therefore, this study was conducted to produce biochar from cucumber green waste collected from a greenhouse in Qatar. The green waste was cut into small pieces (5 to 10 cm) for oven drying at a temperature of 105 °C for 24 h to remove moisture and was then pyrolysed in a muffle furnace at three temperatures of 300, 350, and 550 °C with a heating rate of 5 °C min-1 and residence time of 30 min. This study focuses on the nutrient analysis of biochar, including yield, pH and electrical conductivity (EC). Additionally, a small-scale pot test with cucumber plants applied 0% (control) and 2% biochar to a coco-peat substrate under a controlled microclimate with an enriched CO2 environment of 1000 ppm in a climate chamber. The pots were irrigated with a nutrient rich solution. Results demonstrate that the biochar produced with a higher pyrolysis temperature has a higher C content of 71%, pH of 10.59 and EC of 12.93 mS cm-1 with more aluminium, copper, and manganese. The lower pyrolysis temperature biochar possessed a higher N content of 3% and improved biochar yield of 48% with maximum potassium and iron concentrations. The application of 2% biochar was found to be linked to a maximum increase of 39% in plant height, 32% in leaf area, 3% in chlorophyll content, and a reduction of 71% in water loss by drainage as compared to the control. Moreover, both low and high temperature biochar applications display good plant growth by reducing water loss, while nutrient loss was more significant in the 2% biochar application at all three temperature conditions than the control. This study demonstrates that a lower fraction of biochar application could be beneficial for sustainable agricultural practices to reduce water drainage and nutrient supply. [ABSTRACT FROM AUTHOR]

Coffee is one of the world's most traded commodities grown in about 80 countries and widely consumed. Accordingly, a high quantity of spent coffee grounds (SCGs) produced from coffee beverage preparation is generated and disposed globally. The high availability and low cost of SCG allow its valorization to obtain a valuable product that could be used as an alternative adsorbent for water treatment applications. This study used dried SCG to produce biochar by pyrolyzing the biomass at three different temperatures: 300, 450, and 600 °C. Pyrolysis was conducted at a slow heating rate of 5 °C.min-1 for 30 min. SCG biomass and biochar were characterized for various properties that would describe the biomass changes during pyrolysis and the effectiveness of biochar for water treatment applications. The SCG biomass was acidic in nature with a pH of 5.54, whereas biochar was mildly alkaline with a pH of 7.5 to 10.6, increasing with pyrolysis temperature. The electrical conductivity of SCG biochar at 600 °C (2,278 µS.cm-1) was higher than that of biomass (550 µS.cm-1). This indicates SCG biochar could have promising ion-exchange capacity. SCG biochar produced at 450 °C has the most negative zeta potential of -57.33 mV, compared to the least negative measure of -30.73 mV for SCG biomass. A negative zeta potential has a strong affinity for positively charged cations and this was confirmed through cation exchange capacity (CEC) measurements. The highest CEC was 29 cmolc.kg-1 for 450 °C SCG biochar, a 58 % increase over that for the SCG biomass. SCG biochar contained 63 % to 88 % of C content for pyrolysis temperatures of 300 to 600 °C, respectively, whereas the SCG biomass had a C content of 43 %. With increasing temperature, the fixed carbon (FC) content of biochar increases and reached 69 % at 600 °C, while in biomass, the FC content was only 13 %. The large change in C content as SCG biomass is pyrolysed indicates large changes in structure and therefore tunability. SCG could be a promising carbonaceous adsorbent to remove organic and inorganic pollutants from polluted water. [ABSTRACT FROM AUTHOR]

The citrus industry is considered one of the main contributors to agricultural waste. Peels are commonly used in the food industry or as feedstock in biorefining. In this study, the potential of waste orange peel biochar for agricultural applications in sandy soil was investigated. This will not only increase the percentage of agricultural waste recycling, but also lead to more sustainable agriculture with environmental benefits such as carbon sequestration. Biochar was produced through slow pyrolysis in the temperature range 300–600°C and at two holding durations (10 min and 60 min). Both factors had a significant impact on the physicochemical characteristics of biochar in the heating region 300–450°C. However, varying the holding time for pyrolysis temperatures beyond 450°C had a diminishing effect on biochar properties compared with the impact of increasing pyrolysis temperature. The study also looked at certain properties that are specific to agricultural application not previously reported for orange peel. Very high cation exchange capacities of 70 cmol kg−1 were achieved at 300°C, whereas water holding capacity was not strongly influenced by pyrolysis conditions. Preliminary planting tests indicate potential for improving agricultural sustainability in sandy soils. The technoeconomic analysis of biochar showed that the pyrolysis process can be profitable with sufficient plant capacity. [ABSTRACT FROM AUTHOR]

A study of sorption of aqueous organics by aquifer materials was undertaken with an objective to correlate sorption parameters with the octanol-water partition coefficient (KOW) of aqueous samples. In the first phase, synthetic samples were equilibrated with the aquifer material collected from the river bank filtration (RBF) site located on the bank of the river Alaknanda at Srinagar, Uttarakhand, India. In the second phase, water from the river Hindon at Barnawa, Uttar Pradesh, India, was stirred with the Srinagar aquifer material, and a sample of water from the Elbe River was mixed with the aquifer material from the RBF site in Torgau, Germany. The fraction of organic carbon content (foc) in the aquifer material from Srinagar and Torgau was 0.018 and 0.0027 mg=mg, respectively. The hydrophilic and hydrophobic nature of the synthetic samples and the water samples from the rivers Hindon and Elbe were determined by measuring KOW and specific ultraviolet absorbance (SUVA). Empirical correlations between log KOW and (1) adsorption capacity (Qm), (2) soil-water partition coefficient (Kd), and (3) organic carbon-water partition coefficient (logKOC) for hydrophilic and hydrophobic samples have been developed. The values predicted from the model and experimental observations were statistically analyzed by the regression analysis model (RAM) and analysis of variance (ANOVA). The analysis did not indicate a significant difference between the experimental data and computed data of sorption parameters from log KOW. The similarity between log KOC from (1) Kd (slope of the sorption isotherm) and (2) log KOW was within a 95% confidence limit. The Freundlich isotherm constant (KF) has been found to increase with an increase in KOW, whereas no such correlation was noted for the Langmuir isotherm constant (KL). A correlation between the sorption parameters (Qm, Kd, and KOC) and SUVA was not observed. [ABSTRACT FROM AUTHOR]

This study investigates the production of high-performance activated carbon (AC) from coconut shells (CS) through acid and base activation processes, along with pre- and post-functionalization of the biochar, aiming to effectively remove dyes from aqueous solutions. The resulting AC exhibited outstanding adsorption capabilities, with the Langmuir model providing a good fit to the experimental data. Maximum adsorption capacities were observed at different temperatures: 805 mg g -1 at 298 K, 904 mg g -1 at 318 K, and 1000 mg g -1 at 338 K for NaOH-activated AC, and 252 mg g -1 at 298 K, 295 mg g -1 at 318 K, and 305 mg g -1 at 338 K for H 2 SO 4 -activated AC. The presence of active sites and functional groups on the surface of AC facilitated dye adsorption. The influence of various parameters, including adsorbent dosage, dye concentration, pH, and temperature, on the adsorption process were also examined, identifying the ideal conditions for dye removal. Thermodynamic analysis confirmed the endothermic nature of the adsorption process, with higher temperatures leading to increased adsorption capacities. Overall, the research highlights the potential of various activation routes for the production of high-value AC as a sustainable and effective adsorbent for dye removal from wastewater., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)