Stipa Tenacissima Research Articles

Single-step pyrolysis of Stipa Tenacissima fibers to hard carbon: A potential route for sodium-ion battery anodes

Hard Carbon (HC) has emerged as a viable candidate for the negative electrode material in sodium-ion batteries (SIBs). This study focuses on the development of a novel HC-negative electrode derived from the pyrolysis of Stipa tenacissima fibers (STF). Prior to pyrolysis, STF underwent a hot water wash pre-treatment, and various pyrolysis temperatures (800 °C, 1000 °C, and 1300 °C) were investigated to elucidate their influence on HC properties and performance. Structural analysis revealed significant differences in the HC structure, highlighting a direct correlation between capacity improvement and the size of accessible micropores for sodium insertion. Composite electrodes were assembled and evaluated in non-aqueous sodium half-cells to assess HC's performance. Notably, increasing the pyrolysis temperature resulted in higher reversible capacity (RC). Specifically, HC prepared at 1300 °C exhibited an RC of 270 mAh g−1, initial coulombic efficiency (ICE) of approximately 60 %, and exceptional reversibility with 99 % capacity retention after 90 cycles at a 25 mA g−1 of current density (CD). These results surpassed those obtained with HC prepared at 800 °C and 1000 °C. Moreover, this study explores the biological, biochemical, biophysical, and structural advantages conferred by STF, making it a promising component in SIBs, with the ultimate goal of establishing long-lasting, high-performance battery systems.

Monitoring vegetation cover trends in the steppe region of western Algeria using MODIS imagery

The steppe region of Chehaima (Tiaret Province, northwestern Algeria) covers an area of 2,202 km², representing 10.94% of the total area of Tiaret. This study identified the ecological state of the area using a spatial theme from a 24-year synchronized moderate-resolution imaging spectroradiometer (MODIS) satellite image campaign (2000–2023). The adopted method consists of analyzing spectral indices (normalized difference vegetative index, low surface temperature (LST), and soil moisture index) from MODIS sensors (MOD13Q1), making it possible to evaluate the spatiotemporal dynamics of the vegetation in the study area and to identify regions degraded by several biotic and abiotic factors. The results show a vegetation cover rate of intense fluctuations in unfavorable conditions over 24 years. The percentage of plant growth recorded does not exceed 32%. The abundance of LST vegetation decreases when the LST exceeds 35°C, with a soil that has a water deficit. The De Martonne aridity index (<em>I</em>) classifies the study area as a lower semiarid bioclimatic zone. These indicators made it possible to determine the spatiotemporal dynamics of vegetation, which modifies the plant cover, leading to the loss of native species such as alfa <em>Stipa tenacissima</em> L. Defensive measures are necessary over large areas of the study area to allow successful protection of steppe rangelands through a sustainable conservation strategy, preserving endemic species, stabilizing dunes, and adopting the steppe rotation system.

Native plant species growing on the abandoned Zaida lead/zinc mine site in Morocco: Phytoremediation potential for biomonitoring perspective.

This study aims to assess the level of metal contamination and the ecological risk index at the abandoned Zaida Pb/Zn mining site in eastern Morocco and identify native plant species found on the site that can be used in site rehabilitation through phytoremediation strategies. Samples from seven native and abundant plant species at the site, along with their rhizospheric soils, were collected and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine the concentrations of various metal(loid)s, including As, Cu, Ni, Cd, Sb, Zn, and Pb. Indicators of soil pollution and ecological risks were also assessed, including the enrichment factor (EF), pollution index (PI), and ecological risk index (ERI). The Biological Accumulation Coefficient (BAC), Translocation Factor (TF), and Biological Concentration Factor (BCF) of plant samples were calculated. The results reveal polymetallic soil contamination, with notably higher concentrations of Pb, Cu and Zn, reaching respectively 5568 mg kg-1 DW, 152 mg kg-1 DW, and 148 mg kg-1 DW, indicating a significant potential ecological risk. The enrichment factor (EF) was also assessed for each metal(loid)s, and the results indicated that the metal contamination was of anthropogenic origin and linked to intensive mining activities in Zaida. These findings are supported by the pollution index (PI) ranging from 1.6 to 10.01, which reveals an extremely high metal(loid)s pollution level. None of the plant species exhibited a hyperaccumulation of metal(loid)s. However, Artemisia herba alba demonstrated a strong capacity to accumulate Pb in its aboveground parts, with a concentration of 468 mg kg-1 DW. Stipa tenacissima, Retama spherocarpa, and Astragalus armatus, showed a significant Pb accumulation in their roots reaching 280, 260, and 256 mg kg-1 DW.respectively. Based on BAC, TF, and BCF, Stipa tenacissima exhibited potential for Ni and Cd phytostabilization, as well as the ability for Zn phytoextraction. Additionally, Artemisia herba alba displayed the capability to phytoextract Cd and had a high propensity to translocate all the studied metal(loid)s. Astragalus armatus has the potential to be used in the phytostabilization of Zn and Ni, as well as for the phytoextraction of As and Sb. These native species from the Zaida site, although not hyperaccumulators, have the potential to contribute significantly to the phytoextraction or phytostabilization of potentially toxic elements (PTEs). Moreover, they can serve as vegetative cover to mitigate the erosion and dispersion of metal(loid)s.

Transpiration Dynamics of Esparto Grass (Macrochloa tenacissima (L.) Kunth) in a Semi-Arid Mediterranean Climate: Unraveling the Impacts of Pine Competition.

Macrochloa tenacissima (M. tenacissima), or esparto, is a perennial tussock grass that coexists with Pinus halepensis (P. halepensis) in semi-arid Mediterranean woodlands. This research was carried out to explore diurnal transpiration at leaf level in esparto grass under different levels of pine-esparto competition and in contrasting environmental soil water conditions. The measurement period spanned from the summer of 2020 to the spring of 2021. The relationship between transpiration and competition was conducted in open and closed P. halepensis stands, and the type of leaf (green, senescent) and the maturity of the esparto grass were taken into account. We observed a higher control of transpiration in green leaves, and the correlations between the transpiration and pine competition were noted exclusively in this type of leaf. Our results demonstrated a significant impact of pine competitors (closed stands) on the transpiration of esparto grass, particularly during seasons characterized by scenarios of high water demand: the summer drought period and the commencement of the growing and flowering period (spring). Furthermore, our findings revealed a greater response to transpiration in mature bushes compared to young ones under severe water stress, indicating a higher adaptation to drought by esparto as it ages. Although our results confirmed that PAR increased transpiration in all seasons and in both stands, which is attributable to the heliophilia of esparto grass, the site effects on transpiration could also be attributable to competition for water, especially during periods of drought. These results may have important implications for the dynamics and management of these semi-arid mixed woodlands, as well as the planning of reforestation programs aimed at restoring esparto grass formations.

Ecophysiological traits of seedlings from different accessions of Stipa tenacissima along a climatic gradient

Predicting the future impact of climate change on Stipa tenacissima steppes is of paramount importance to prevent desertification. From this perspective, we selected seven populations, covering a rainfall range from 100 to 600 mm/year at the sites of seed collection, and we grew the seedlings at the same site. Gas exchange measurements of CO2, light response curves, chlorophyll content and isotopic analysis were investigated. Thala and Valencia populations displayed a contrasted gas exchange response. Both populations were subjected to A-Ci curve analysis. No significant difference was detected between these two different populations in the maximum rate of carboxylation (Vcmax) and the maximum rate of electron transport (Jmax). Stipa tenacissima exhibited a variable response in relation to different light intensities. Photosynthesis and chlorophyll fluorescence parameters proved to be significantly different among populations in response to light intensities. All populations exhibited similar chlorophyll content. The isotopic analysis highlighted a different carbon and nitrogen isotopic composition (δ13C and δ15N) and carbon content © among populations. Mesic populations presented a higher gas exchange activity and light response. The xeric populations performed a photosynthesis adjustment along with minimizing chlorophyll content. Under climate change, S. tenacissima limits productivity, which may lead to desertification.

Pushing the limits of C3 intrinsic water use efficiency in Mediterranean semiarid steppes: Responses of a drought‐avoider perennial grass to climate aridification

Abstract Intrinsic water use efficiency (WUEi) reflects the trade‐off between photosynthetic carbon gain and water loss through stomatal conductance and is key for understanding dryland plant responses to climate change. Stipa tenacissima is a perennial tussock C3 grass with an opportunistic, drought‐avoiding water use strategy that dominates arid and semiarid steppes across the western Mediterranean region. However, its ecophysiological responses to aridification and woody shrub encroachment, a major land‐use change in drylands worldwide, are not well‐understood. We investigated the variations in leaf stable isotopes (δ18O, δ13C, δ15N), nutrient concentrations (N, P, K), and culm water content and isotopic composition (δ18O, δ2H) of paired pure‐grass and shrub‐encroached S. tenacissima steppes along a 350 km aridity gradient in Spain (10 sites, 160 individuals). Culm water isotopes revealed that S. tenacissima is a shallow‐rooted grass that depends heavily on recent rainwater for water uptake, which may render it vulnerable to increasingly irregular rainfall combined with faster topsoil drying under climate warming and aridification. With increasing aridity, S. tenacissima enhanced leaf‐level WUEi through more stringent stomatal regulation of plant water flux and carbon assimilation (higher δ13C and δ18O), reaching exceptionally high δ13C values (−23‰ to −21‰) at the most arid steppes. Foliar N concentration was remarkably low across sites regardless of woody shrub encroachment, evidencing severe water and N co‐limitation of photosynthesis and productivity. Shrub encroachment decreased leaf P and K but did not affect S. tenacissima water status. Perennial grass cover decreased markedly with both declining winter rainfall and shrub encroachment suggesting population‐level rather than individual‐level responses of S. tenacissima to these changes. The fundamental physiological constraints of photosynthetic C3 metabolism combined with low foliar N content may hamper the ability of S. tenacissima and other drought‐avoider species with shallow roots to achieve further adaptive improvements in WUEi under increasing climatic stress. A drought‐avoiding water use strategy based on early stomatal closure and photosynthesis suppression during prolonged rainless periods may thus compromise the capacity of semiarid S. tenacissima steppes to maintain perennial grass cover, sustain productivity and cope with ongoing climate aridification at the drier parts of their current distribution. Read the free Plain Language Summary for this article on the Journal blog.

Influence of Anatomy, Microstructure, and Composition of Natural Fibers on the Performance of Thermal Insulation Panels.

The growing interest in environmentally friendly materials is leading to a re-evaluation of natural fibers for industrial applications in order to meet sustainability and low-cost objectives, especially for thermal insulation of buildings. This paper deals with the chemical and physical characterization of fibers extracted from seagrass (Posidonia oceanica) and alfa grass (Stipa tenacissima) for a possible substitution of synthetic materials for thermal insulation. Hemp (Cannabis sativa), a fiber broadly used, was also studied for comparison. The parameters characterized include porosity, thermal degradation, elemental composition, skeletal and particle density of the fibers as well as investigation of the thermal conductivity of fiber-based panels. Several technologies were involved in investigating these parameters, including mercury intrusion, thermogravimetric analysis, fluorescence spectroscopy, and fluid pycnometry. The fibers showed a degradation temperature between 316 and 340 °C for Posidonia, between 292 and 326 °C for alfa, and between 300 and 336 °C for hemp fibers. A high porosity allied with a reduced pore size was revealed for Posidonia (77%, 0.54 μm) compared to hemp (75%, 0.61 μm) and alfa (57%, 2.1 μm) raw fibers, leading to lower thermal conductivity values for the nonwoven panels based on Posidonia (0.0356-0.0392 W/m.K) compared to alfa (0.0365-0.0397 W/m.K) and hemp (0.0387-0.0427 W/m.K). Bulk density, operating temperature, and humidity conditions have been shown to be determining factors for the thermal performance of the panels.

Assessing canopy rainfall partitioning by Mediterranean dryland shrubs under extreme rainfall

AbstractIntense rain events have become more frequent in some regions due to climate change, and this trend is particularly concerning in dryland regions where the ecological and geomorphological impacts of rainfall are intimately tied to its intensity. The interception of rainfall by vegetation is a critical process in the water balance of drylands; thus, this study estimated the canopy interception capacity and interception rates as well as stemflow of three typical Mediterranean shrub species (Rosmarinus officinalis, Thymus vulgaris, and Macrochloa tenacissima) of three size classes in Spain under a simulated extreme rainfall rate (~8 mm min−1, historical return period of >100 years). Given that these plants' canopy structures markedly differ from taller woody plants (i.e., trees), a novel method was developed to assess the stemflow fraction. Results showed significant differences in interception amount, rates, and storage capacity among the shrub species, with variations in plant morphology, such as shrub height and canopy diameter, being the key factors determining interception capacity. R. officinalis had the highest interception fraction per unit canopy area, or ‘specific interception,’ (18.4%). In contrast, the lowest specific interception fraction was measured for M. tenacissima (6.5%). Thymus vulgaris was characterized by the highest stemflow yields per unit canopy area (4.85 mm) and fraction (up to 29.6% of rainfall), which was the lowest for M. tenacissima (1.09 mm, ~1%–4%). Strong linear correlations were found between canopy interception and shrub canopy diameter (|r| > −0.51, max = −0.90), when observations were grouped for size class. These linear correlations between shrub morphology and partitioning enabled multiple‐regression linear models to be developed that predicted canopy interception and stemflow with good accuracy (r2 > 0.64, with a maximum of 0.82) from shrub height, canopy diameter, dry biomass, size class, and species. Despite these measurements being conducted under one extreme storm depth and intensity, the results provide: (i) values of rainfall partitioning for important shrub species in Mediterranean dryland environments; and (ii) a simple but reliable model that may be further developed (e.g., embedding variable rainfall values as weather input or incorporating other morphological parameters) and may be integrated into complex hydrological models.

Thermal and Acoustic Performance of Gypsum Plasters Mixed with Different Additives: Influence of Bio-Based, Synthetic, and Mineral Fillers

Due to the high impact of the building sector on the environment, a growing interest focuses on insulating materials able to ensure good thermo-acoustic performance for the building envelope from a sustainable and circular economy perspective. In this context, Moroccan natural gypsum was mixed with local natural waste materials. The thermal and acoustic properties of the samples were measured; they were compared to those of synthetic- and mineral-based gypsum plasters manufactured with the same technique. A Small Hot Box apparatus was used for thermal characterization, whereas acoustic performance was investigated by means of a Kundt’s Tube. Natural and synthetic additives result in a reduction in density and an improvement in thermal performance. Conductivity values in the 0.181–0.238 W/mK range were obtained, depending on the type of natural additive, with respect to 0.275–0.323 W/mK of mineral-based gypsum plasters. The acoustic measurements showed that all the composites have similar performance in terms of acoustic absorption, whereas high transmission loss values were obtained for the natural additives (TL = 35–59 dB). Petiol of Palm and Stipa Tenacissima were found to be materials able to improve both thermal and acoustic properties.

“Greener” homogeneous esterification of cellulose isolated from Stipa tenacissima plant located in the Eastern region of Morocco using ionic liquids as reaction medium

“Greener” homogeneous esterification of cellulose isolated from Stipa tenacissima plant located in the Eastern region of Morocco using ionic liquids as reaction medium

Short-term Macrochloa tenacissima response understory Pinus halepensis Mill forest after early prescribed burns in a semi-arid landscape

Climate change has led to altered fire patterns in the Mediterranean basin due to rising temperatures and greenhouse gas emissions, diminishing the resilience of forest ecosystems. To address this threat, forest management increasingly employs preventive measures like controlled burns, aiming to mitigate wildfire damage. However, understanding the impact of prescribed burns on vegetation remains crucial.Our study focuses on assessing the ecological effects of early-season prescribed burns on Macrochloa tenacissima communities within Pinus halepensis Mill forests on the Iberian Peninsula. These forests, with southeast-facing slopes and arid soils, heavily rely on alpha grass for post-fire recovery, acting as a shield against runoff and erosion. Yet, the presence of highly flammable resprouting species can lead to rapid combustible material accumulation. We evaluated parameters like coverage, floral diversity (α-diversity), aboveground plant biomass, photosynthetic activity, and chemical leaf properties of alpha grass, a year after a low-intensity controlled burn. Comparing burnt and unburnt areas revealed significant changes in α-diversity and ecophysiology of Macrochloa tenacissima due to early-season prescribed burns. These short-term shifts underscore the need for further exploration of underlying mechanisms.Our analysis also showed distinct shifts in alpha grass leaf chemical composition between the two plot types, potentially impacting post-fire recovery strategies. Although prescribed burning might not be optimal for reducing fire risk in resprouting species-dominated forests, it conserves native plants and enhances ecosystem diversity, providing valuable ecological benefits.In conclusion, our research deepens our understanding of early-season burning's repercussions on flammable vegetation dynamics and combustible material availability in semi-arid landscapes. It contributes to standardized management protocols, aiding effective forest service administration and wildfire risk reduction.

EFFECT OF ALKALINE TREATMENT ON MECHANICAL PROPERTIES OF ALFA FIBER/UNSATURATED POLYESTER COMPOSITE

Researchers are showing increasing interest in plant fiber reinforced composites due to their eco-friendliness, low density, low cost and amazing mechanical properties. However, some challenges remain for researchers in this field, most notably poor adhesion between the polymer matrix and the plant fibers, which reduces the mechanical properties of composites reinforced with these fibers. This study aims to improve the adhesion between the matrix and the reinforcement by chemically treating Alfa fibers (Stipa tenacissima) with a 3 wt% NaOH solution at different times (1, 3, 5 and 24 h). FTIR, DRX, GTA and tensile tests were conducted. XRD tests showed that the crystallinity index of 3% alkali treated Alfa fibers for 5 h increased by 36.26%, compared to that of untreated fibers. The results also revealed that the mechanical properties of composites reinforced with treated fibers outperformed those reinforced with untreated fibers. These findings can contribute to the development of high mechanical performance composites, which can be competitive with those prepared with synthetic fibers.

Exploring the impact of water on the morphology and crystallinity of xylan hydrate nanotiles

There has been a resurgence of studies on xylan particles describing various properties and exploring new applications. The aim of this study was to analyze xylan hydrate crystals in the wet state and after air-drying using state-of-art imaging techniques in order to assess the impact of water on both crystallinity and particle morphology. Xylan from esparto grass (Stipa tenacissima) was crystallized and formed convex platelets, termed ‘nanotiles’. Fully hydrated xylan crystals were examined in a layer of vitreous ice by cryogenic electron microscopy. Selected area electron diffraction of the xylan hydrate crystals revealed an oriented crystalline core, unlike the dried crystals that showed no orientation. The surface topographies and thickness of wet and air-dried xylan nanotiles were observed using atomic force microscopy imaging in both liquid and in air. X-ray diffraction was used to assess the crystallinity of xylan nanotiles after drying to varying levels. Air-dried crystals gave diffraction maxima corresponding to xylan hydrate, while wet crystals gave diffraction maxima corresponding to xylan dihydrate. This study offers new insight into xylan hydrate particles, focusing on the role of water on their crystallinity, ultrastructure, and orientation of the crystalline layers.

Valorization of the use of natural Alfa (Stipa tenacissima L.) fiber in composite reinforcing plates based on natural fibers and metal fabric

Valorization of the use of natural Alfa (Stipa tenacissima L.) fiber in composite reinforcing plates based on natural fibers and metal fabric

Development of BioPolyurethane Coatings from Biomass-Derived Alkylphenol Polyols-A Green Alternative.

Bio-based polyols were obtained from the thermochemical liquefaction of two biomass feedstocks, pinewood and Stipa tenacissima, with conversion rates varying between 71.9 and 79.3 wt.%, and comprehensively characterized. They exhibit phenolic and aliphatic moieties displaying hydroxyl (OH) functional groups, as confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. The biopolyols obtained were successfully employed as a green raw material to produce bio-based polyurethane (BioPU) coatings on carbon steel substrates, using, as an isocyanate source, a commercial bio-based polyisocyanate-Desmodur® Eco N7300. The BioPU coatings were analyzed in terms of chemical structure, the extent of the reaction of the isocyanate species, thermal stability, hydrophobicity, and adhesion strength. They show moderate thermal stability at temperatures up to 100 °C, and a mild hydrophobicity, displaying contact angles between 68° and 86°. The adhesion tests reveal similar pull-off strength values (ca. 2.2 MPa) for the BioPU either prepared with pinewood and Stipa-derived biopolyols (BPUI and BPUII). Electrochemical impedance spectroscopy (EIS) measurements were carried out on the coated substrates for 60 days in 0.05 M NaCl solution. Good corrosion protection properties were achieved for the coatings, with particular emphasis on the coating prepared with the pinewood-derived polyol, which exhibited a low-frequency impedance modulus normalized for the coating thickness of 6.1 × 1010 Ω cm at the end of the 60 days test, three times higher than for coatings prepared with Stipa-derived biopolyols. The produced BioPU formulations show great potential for application as coatings, and for further modification with bio-based fillers and corrosion inhibitors.

Box-Behnken design optimization of xylanase and cellulase production by Aspergillus fumigatus on Stipa tenacissima biomass

ABSTRACT Optimization of xylanase and cellulase production by a newly isolated Aspergillus fumigatus strain grown on Stipa tenacissima (alfa grass) biomass without pretreatment was carried out using a Box-Behnken design. First, the polysaccharides of dried and ground alfa grass were characterized using chemical methods (strong and diluted acid). The effect of substrate particle size on xylanase and carboxymethylcellulase (CMCase) production by the selected and identified strain was then investigated. Thereafter, experiments were statistically planned with a Box-Behnken design to optimize initial pH, cultivation temperature, moisture content, and incubation period using alfa as sole carbon source. The effect of these parameters on the two enzyme production was evaluated using the response surface method. Analysis of variance was also carried out, and production of the enzymes was expressed using a mathematical equation depending on the influencing factors. The effects of individual, interaction, and square terms on production of both enzymes were represented using the nonlinear regression equations with significant R 2 and P-values. Xylanase and CMCase production levels were enhanced by 25% and 27%, respectively. Thus, this study demonstrated for the first time the potential of alfa as a raw material to produce enzymes without any pretreatment. A set of parameter combinations was found to be effective for the production of xylanase and CMCase by A. fumigatus in an alfa-based solid-state fermentation.

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

Natural Cellulosic Alfa Fiber (Stipa Tenacissima L.) Improved with Environment-Friendly Treatment Cementitious Composites with a Stable Flexural Strength

Natural Cellulosic Alfa Fiber (Stipa Tenacissima L.) Improved with Environment-Friendly Treatment Cementitious Composites with a Stable Flexural Strength

Marked Range Regression and Possible Alteration of Distribution of the Dupont’s Lark Chersophilus duponti in Tunisia: Conservation Consequences of Vanishing Alfa Grass Stipa tenacissima Steppes in North Africa

The effect of global warming and desertification on bird populations of semi-arid North African ecosystems has been little studied, although ecosystems in those areas are suffering dramatic changes. Dupont’s lark is one of the most endangered passerines in Europe, but it is also considered scarce in North Africa, where its range and numbers are only well known for Morocco. We analyzed the current distribution and population size of Dupont’s lark in Tunisia and compared the current figures with older data. To assess the presence of the species in the patches of adequate habitat that we found, we elicited territorial calls by broadcasting the males’ territorial songs during early breeding season (N = 123, ≈40 h). Fieldwork (45 persons/day) and analysis of satellite images were combined to determine the current minimal extent of occurrence and area of occupancy, following IUCN definitions. In the only habitat where we found the species (well-preserved pure or mixed alfa patches in the Feriana-Kasserine region), the extent of occurrence in and effective area of occupancy were small (56.3 and 33.2 km2, respectively), particularly when compared with previous estimates (presence of the species in adequate habitat over ca. 89,000 km2). The species has not been detected at all in a large area in the southern part of its potential range, where additional surveys are urgently needed to locate possible remnant small and isolated populations that could persist, as suggested by two recent records of the species there. The breeding population of Dupont’s lark in Tunisia is estimated to be fewer than 600 song birds (335–577). The drastic reduction of range and numbers of this species must have been caused by the disappearance or degradation of alfa grasslands due to agricultural development, overgrazing, and increased aridity.

Biosorption of Triphenyl Methane Dyes (Malachite Green and Crystal Violet) from Aqueous Media by Alfa (Stipa tenacissima L.) Leaf Powder.

This study includes the characterization and exploitation of an abundant agricultural waste in Algeria, Alfa (Stipa tenacissima L.) leaf powder (ALP) as a biosorbent for the removal of hazardous triphenylmethane dyes, malachite green (basic green 4) and crystal violet (basic violet 3), from aqueous media under various operating conditions in batch mode. The effect of experimental parameters such as initial dye concentration (10-40 mg/L), contact time (0-300 min), biosorbent dose (2.5-5.5 g/L), initial pH (2-8), temperature (298-328 K), and ionic strength on dye sorption was investigated. The results of both dyes show that the increase in initial concentration, contact time, temperature, and initial pH of solution leads to an increase in biosorbed quantity, unlike the effect of ionic strength. The biosorption kinetics for triphenylmethane dyes on ALP was analyzed by pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models proposed by the Weber-Morris equation. Equilibrium sorption data were analyzed by six isotherms, namely the Langmuir, Freundlich, Harkins-Jura, Flory-Huggins, Elovich, and Kiselev isotherms. The thermodynamic parameters were evaluated for both dyes. The thermodynamic results suggest that both dyes' biosorption is a typical physical process, spontaneous and endothermic in nature.