Eco-friendly adsorbent from spent mushroom substrate for hexavalent chromium liquid waste treatment

ABSTRACT: Spent mushroom substrates is composted organic material remaining after a crop of mushroom is harvested. The raw materials of mushroom substrates are same feed ingredient as corncobs, rice brown, wheat brown, cotton seeds and beet pulp. During the mushroom cultivation process, the mushroom substrates was used 15-25% by mushroom and 75-85% of mushroom substrates was remained in the SMS. Among of the spent mushroom substrates, spent mushroom substrates of Pleurotus eryngii, Pleurotus ostreatus and Flammuliua velutipes is can be use the energy feedstock of animal feed. The cellulose content of spent mushroom( Pleurotus eryngii) substrates containing the sawdust was high and total digestible nutrients (TDN) values was low. The spent mushroom( Pleurotus eryngii) substrates fermented with cellulase and xylanase producing bacteria is may be used as an ingredient of feed in TMR for Hanwoo steer. KEYWORDS : Feed, Hanwoo steers, Probiotics, Spent mushroom substrates Journal of Mushroom Science and ProductionCopyright ⓒ 2012 by The Korea Society of Mushroom ScienceVol. 10, No 4, p236-243 December 2012Printed in S. Korea

This study was carried out to determine the supplemental level of spent mushroom (Flammulina velutipes) substrates as an energy source in manufacturing of high moisture sorghum whole crop silage. Whole crop sorghum was harvested at heading stage and ensiled with spent mushroom substrates of 20% (S-20), 40% (S-40) and 60% (S-60) as fresh matter basis. Each silage was manufactured in plastic buckets included vinyl bag by three replications and stored for 0, 3, 6 and 9 weeks, respectively. Fermentation characteristics and quality of sorghum silages manufactured by supplemental level of spent mushroom substrates were as follows. Moisture contents of whole crop sorghum and spent mushroom substrates were 83.85% and 54.3%, respectively, and that of silages was 78% for S-20, 71% for S-40 and 68% for S-60. Ether extracts content of silages was significantly (P<0.05) increased during the fermentation periods. The pH in silages fermented for 3 weeks and above ranged from 4.24 to 4.42, and the decrease of pH by fermentation was relatively greater in S-40 compare to the other treatments. The lactic acid content of silage inclined that the S-40 was higher compared to the other treatments and decreased with elongation of fermentation period of silage. The contents of acetic acid and propionic acid of silages were not influenced by treatments and fermentation period. Flieg's score for estimation of silage quality ranged from 60 to 83, and was relatively high quality in the S-40 fermented for 9 week, and was relatively low quality in the S-60 fermented for 9 week. From above results, we suggest that 40% supplementation of spent Flammulina velutipes mushroom substrates as an energy source is resonable level in manufacturing of high moisture sorghum whole crop silage.

Pesticide residues from agrochemicals pose significant environmental and public health risks due to their persistence and widespread contamination of soil, water, and crops. The persistent challenge of pesticide contamination requires innovative and sustainable treatment strategies to safeguard public health and environmental integrity. Although wastewater treatment plants (WWTPs) are designed to mitigate these pollutants, their efficiency varies, and certain pesticides persist or transform into more toxic by-products during treatment. Therefore, developing alternative methods for the effective removal of pesticide residues is imperative. This review critically evaluates the potential of adsorption, particularly using green adsorbents, as a sustainable and efficient approach for removing pesticide contaminants from soil and wastewater. Green adsorbents, derived from agricultural and industrial by-products such as sea materials, biomasses, humic acid, spent mushroom substrate, biochar, and cellulose-based adsorbents, offer a cost-effective, abundant, and environmentally friendly solution for soil treatment and water purification. Their high pollutant-binding capacity, selectivity, and affinity make them promising candidates for widespread application in soil and wastewater treatment. Ongoing research focuses on optimizing the scalability and real-world application of these adsorbents for large-scale remediation efforts. In conclusion, addressing the risks posed by pesticide residues necessitates revisiting agricultural practices and wastewater treatment strategies. The integration of green adsorbents offers a sustainable approach to mitigating pesticide contamination, thereby protecting public health and supporting environmental sustainability. This review highlights the importance of adopting green adsorbents as viable alternatives to conventional treatment methods, emphasizing their potential to revolutionize wastewater management and mitigate the adverse impacts of pesticide residues on ecosystems and human well-being.

The removal of caesium radionuclides from an aqueous solution by flotation using rice straw (RS) agricultural waste as a low-cost and eco-friendly adsorbent in the presence of potassium ferrocyanide (KFC) was investigated. The influence of many adsorption parameters and flotation was evaluated on the removal efficiency of 137Cs. The adsorption results demonstrated that the concerned radionuclide was efficiently removed in the presence of 2 × 10−4 mol/L KFC using 10 g/L RS at pH ≥ 7. The double exponential kinetic model and the Freundlich model were the best models for fitting the adsorption kinetic and isotherm data, respectively. The maximum adsorption capacity of RS, calculated from the Langmuir model, was 280.405 mg/g. after being transferred to the flotation cell, 137Cs loaded onto ferrocyanide-modified rice straw (FMRS) was successfully floated at pH 7 using 3 × 10−4 mol/L cetyltrimethylammonium bromide (CTAB) surfactant in the presence of 4% ethanol. Removal percentages of 56% and > 99.5% were achieved for 137Cs-loaded FMRS within 5 min using sodium dodecyl sulphate (SDS) and CTAB, respectively. The results obtained in this investigation indicate the efficiency of the suggested strategy and hence its applicability for the removal of 137Cs+ from radioactive liquid wastes.

As a traditional method of waste treatment, municipal solid waste incineration (MSWI) has become one of the main methods of urban waste treatment. However, as a byproduct of MSWI, a large amount of MSWI bottom ash is not reused in current practice. This study innovatively posits MSWI bottom ash as an eco-friendly adsorbent rather than a pollutant, exploring its potential application as a permeable subgrade material. The results reveal that MSWI bottom ash exhibits promising properties to serve as a permeable subgrade material to achieve the permeability and improve the sustainability for subgrade. Due to the arrangement of its particles, it shows excellent performance in shear strength and permeability, which are comparable to or surpass those of sandy soils. The average pore width of 14.200 nm allows heavy metal substances to be encapsulated within the matrix, significantly reducing their leachability, thereby aligning with environmental friendliness standards. Its adsorption capacity is about 6.60 mg/g, and the adsorption capacity per volume is 3.66 times and 2.04 times that of fly ash and clay, respectively. The mechanism analysis shows that the adsorption process is monolayer heterogeneous adsorption. This paper presents a novel perspective on reusing MSWI bottom ash and provides evidence supporting its effective utilization as a permeable subgrade material, offering substantial environmental benefits through enhanced adsorption ability. Implications: Municipal solid waste incineration (MSWI) is a common method for municipal solid waste treatment, while the MSWI bottom ash is often not reused. This paper explored the explores the feasibility of using MSWI bottom ash as a permeable road base material. The results show that the particle arrangement enables excellent shear strength and permeability, comparable to sandy soil. It meets safety requirements for the leaching of heavy metals and acts as an adsorbent for pollutants leaching from permeable pavements. Furthermore, the mechanisms underlying these behaviors of MSWI were confirmed by microstructural and mineralogical analyses. These indicate that MSWI bottom ash has great potential as a permeable road base material. This paper provides a clear understanding of the physical, mechanical and environmental properties of MSWI bottom ash, which can promote its reuse in practice.

Effects of spent mushroom substrate biochar on growth of oyster mushroom (Pleurotus ostreatus)

Hexavalent chromium in drinking water is reported as well known carcinogen. This paper examines an efficient adsorption process of Cr(VI) from drinking water. The ability of developed Eucalyptus (Eucalyptus globulus) bark carbon as an adsorbent for Cr(VI) removal from synthetic sample was studied. The experiments were done in the batch process. Effects of adsorbent quantity, pH, contact time, initial Cr(VI) concentration and agitation rate were investigated on removal of chromium(VI). Approximately 95% of hexavalent chromium (10 mg L−1) was removed at pH 3 within 21 hours at 150 rpm and the concentration reached upto permissible limit recommended by standard agencies. The results indicate that the Langmuir model fits the data better than the Freundlich adsorption isotherm model. The adsorption follows second order kinetics for Cr(VI) removal in this study. The maximum adsorption capacity of 23 mg g−1 was found for the Cr(VI) adsorption. Characterization of the developed adsorbent was performed by SEM and EDX analysis and the results of the characterization supported surface nature and composition of the adsorbent.

The potential of Pterocladia capillacea, a marine red seaweed, as a sustainable and eco-friendly adsorbent was investigated for the removal of toxic hexavalent chromium Cr(VI) (or Cr6+) and crystal violet dye (CVD) from contaminated water. Characterization of P. capillacea using Fourier-Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis revealed a porous structure with a high specific surface area (87.17 m²/g) and a negative surface charge (-29.5 mV), ideal for adsorbent applications. Adsorption studies were conducted to assess the impact of operational parameters, such as pH, adsorbent dose, initial pollutant concentration, and temperature. Optimal removal was achieved at pH 1.0 for Cr6+ and CVD. Increasing the adsorbent dose led to higher Cr6+ adsorption, achieving near-complete removal with 0.4 g. An optimal dose of 0.8 g was selected for subsequent experiments. Cr6+ Cr6+ removal was faster during the initial adsorption stage (within 30–60 min), followed by a slower rate due to saturation and reduced pore diffusion. Adsorption was more effective at lower temperatures and followed pseudo-second-order kinetics, suggesting chemisorption as the dominant mechanism. Six isotherm models were used to describe equilibrium adsorption, with the Freundlich model providing the best fit for both Cr6+ and CVD, indicating multilayer adsorption and heterogeneous surface interactions. P. capillacea showed potential for Cr6+ removal in seawater and real wastewater, although efficiency was reduced due to complex matrix effects. Reusability studies indicated a decline in efficiency over multiple cycles; however, Cr6+ uptake remained above 89.2% for CVD. Similar reusability was observed, with an initial removal efficiency of 87.29% for CFD. Although removal efficiency decreased in subsequent cycles, the material remained effective for repeated CVD adsorption. The study demonstrates the potential of P. capillacea as a readily available, cost-effective, and sustainable material for the bioremediation of Cr6+ and synthetic dyes from water, contributing to the development of environmentally friendly water treatment technologies.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-15361-6.

The contamination of water by heavy metals, particularly hexavalent chromium (Cr(VI)), poses a serious threat to aquatic life and human health. Developing low-cost and eco-friendly adsorbents from agricultural waste offers a sustainable solution to this problem. In this context, potato peels, an abundant agro-waste, can serve as an efficient biosorbent for Cr(VI) removal. This study investigates the potential of potato peels (RPP) as a cost-effective and sustainable material for the removal of Cr(VI) from aqueous systems. The RPP was characterized using several techniques including FTIR, pHpzc, TGA/DTG, and XRD. The effect of various adsorption parameters was examined, such as initial pH (2-5), contact time (0-360 min), initial concentration (10-200 mg L-1), and solution temperature (30-50 °C). A maximum chromium (VI) adsorption capacity of 15.09 mg g-1 was achieved under optimal conditions of pH 2, initial concentration 100 mg L-1, adsorbent dosage of 4 g L-1, and contact time of 360 min. Isotherm analysis showed that the Langmuir model fit the data (R2 = 0.98), indicating monolayer adsorption behavior. Kinetic data followed a pseudo-second-order model indicating a chemisorption process. Furthermore, thermodynamic analysis revealed negative ΔG° < 0, while ΔH° = 44.13 kJ mol-1 > 40 kJ mol-1 and ΔS° = 145.80 kJ mol-1 K-1, suggesting that the process is spontaneous and endothermic. Desorption and reusability studies confirmed successful adsorbent reuse for three cycles. These findings indicate that potato peel waste is an environmentally friendly and effective biosorbent for the removal of chromium (VI) from aqueous media.

Mushroom cultivation generates a large volume of SMS (spent mushroom substrate), which needs to be properly discarded to avoid contamination of new production cycles. However, SMS is a rich substrate, and can be used to produce vegetable seedlings. The present study evaluated the feasibility of using SMS of Agaricus bisporus as substrate for production of sweet pepper seedlings. The culture substrate was composed of sugar cane bagasse, horse manure, rice straw, soybean meal, chicken bed, urea, potassium chloride, simple superphosphate and gypsum. After cultivation, the SMS was homogenized, wet and composted. The substrate thus processed is the SMS of A. bisporus. The substrate Carolina II® was used as control. The following treatments were evaluated: T1- 100% Carolina II; T2 - 25% SMS + 75% Carolina II; T3-50% SMS + 50% Carolina II; T4- 75% SMS + 25% Carolina II and T5- 100% SMS). Seedling and germination characteristics were evaluated. The best germination parameters were observed with the treatment containing 50% of SMS, compared to the commercial substrate. However, for the quality parameters of the seedlings, the best results were obtained with 100% SMS treatment. Therefore, the use of different SMS percentages for the production of pepper seedlings is an alternative to reduce the production cost. The treatment with 100% SMS presented the best DQI values, as it produced vigorous and better quality pepper seedlings.

Soil health is one of the most important factors that influence plant productivity. Incorporation of soil into plant residues that are high in organic matter has been reported to improve soil’s physical and chemical properties which enhance plant growth and development. Therefore, the objective of this study was to investigate the effect of soils amended with different spent oyster mushroom substrates on seedling emergence and growth of spinach (Spinacia oleracea). The respective soil samples were amended with different Spent Mushroom Substrates (SMS) at ratio 60:40 (soil/substrate). Treatments were: T1= U. panicoides + soil, T2= Z. mays + soil, T3= D. stramonium + soil, T4= Substrate mix [60% soil: U. panicoides (13.33%), Z. mays (13.33%) and D. stramonium (13.33%)] and T5= un-amended soil (100%). The respective treatments were filled into 25cm diameter pots and arranged in a Complete Randomized Design (CRD) in a temperature-controlled glasshouse. In each respective pot, three S. oleracea seeds were planted at a depth of 2cm and watered 3 times a week. S. oleracea growth response was determined by assessing the following variables: emergence rate, plant height, number of leaves/plant and chlorophyll content over a period of 12 weeks. Total dry biomass was assessed at harvest by oven drying the plants at 60ºC for 72 hrs. On the first assessment, seedlings raised in Z. mays SMS had significantly higher emergence percentage than seedlings raised in D. stramonium, Substrate mix, U. panicoides SMS (p&lt;0.05). Seedlings raised in Z. mays SMS attained 100% emergence 7 days after planting (DAP), and un-amended soils had 91.75% 9 DAP. Seedlings raised in Z. mays and D. stramonium SMS had significantly higher plant height than seedlings raised in U. panicoides SMS and un-amended soils (p&lt;0.05). Seedlings raised in Z. mays SMS attained 26.27cm height compared to U. panicoides SMS and un-amended soils which attained 12.67cm and 14cm height, respectively. Findings of this study revealed that Z. mays and D. stramonium SMS amended soils have inherent properties that positively influenced the seedling emergence, establishment, and growth of S. oleracea. This would, therefore, have influence on the leaves which are the main agronomic yield of the crop. Key words: Spent mushroom substrates (SMS), Oyster mushroom, Spinacia oleracea, Urochloa panicoides, Datura stramonium, Zea mays, Seedling emergence, Germination

Mushroom farming is environment-friendly, utilizing agricultural, poultry, and brewery residues. Spent mushroom substrate (SMS) is a by-product after several mushroom cultivation cycles. SMS may contain beneficial microorganisms with potential antagonistic activity against phytopathogens. The use of oyster mushroom substrates has shown promising results in managing various plant diseases. This study explores the antimicrobial potential of water extracts from spent mushroom substrate (SMS) of various Pleurotus species, a byproduct of oyster mushroom cultivation. LCMS analysis identified several bioactive compounds with known antimicrobial properties: Pleurotus sajor-caju SMS contained 3-(o-chlorophenyl)-5-(ptolyloxymethyl)-2-oxazolidone; Pleurotus sapidus SMS revealed the presence of Cichoriin, Ethiin, and Cafestol palmitate; while Pleurotus ostreatus SMS showed Bronopol and Daphnetin-8-glucoside. These findings demonstrate the presence of natural antimicrobial agents in Oyster mushroom SMS, suggesting its potential as an eco-friendly, sustainable alternative for managing soil-borne fungal plant pathogens. This approach not only supports environmental sustainability but also adds value to agricultural waste through its application in plant disease management.

Simple SummaryVelvet antler from sika (and other deer species) is a highly valued nutraceutical in traditional Chinese medicine, a market of hundreds of million dollars. Thus, in this case, and in deer breeding in general, reducing the feeding cost of male sika deer is important to improving the profitability of breeding for velvet antlers. Spent mushroom substrate (SMS) is a waste culture medium for mushrooms. The improper handling of SMS causes environmental pollution. Since SMS can be digested and absorbed by ruminants such as sika deer, replacing SMS with a sika deer concentrate supplement can fully utilize the waste resource of SMS and reduce the production cost of velvet antler.At present, spent mushroom substrate (SMS) is a waste resource that is producing a pollution problem in China, and which has some use as animal feed or fertilizer, has not been assessed as a feed for deer. The purpose of this study is to expand the feed of male sika deer and reduce the feeding cost by using the waste resource of SMS. The 10% concentrated supplement was replaced with SMS and the feed intake, apparent digestibility, blood index and velvet production of male sika deer were measured. As the results showed, compared to the control group, the substitution of SMS for 10% of the concentrate supplement decreased the concentration of IgA (p < 0.01), replacing 10% concentrated supplement with SMS of Pleurotus ostreatus (SMS-MP) reduced the intake of organic matter (OMI) and improved the digestibility of ether extract (EE), while replacing 10% concentrated supplement with SMS of Flammulina velutipes (SMS-MF) had no effect on apparent nutrient digestibility, feed intake, velvet antler production, and biochemical indexes. In conclusion, SMS had no effect on serum biochemical indexes and the ratio of the feed weight of the deer supplement to the weight of velvet antler (p > 0.05). At the same time, SMS could reduce the feed consumption and improve the economy by using SMS as a waste resource.

Effective Microbes (EM) formulations and spent mushroom substrate (SMS) are valuable in sustainable agriculture due to their beneficial microbial content. This study aims to culture, isolate, and identify microbial populations in EM and SMS using morphological analysis techniques. The samples included in this study are: Sample 1 (control): distilled water, Sample 2: spent mushroom substrate (SMS), Sample 3: EM with SMS, and Sample 4: EM. pH extraction was performed for each sample to assess conditions, yielding the following values: Sample 1 – 7.20, Sample 2 – 6.50, Sample 3 – 3.67, and Sample 4 – 6.72, indicating varying acidity levels. Microorganisms were cultured on Potato Dextrose Agar (PDA) media, promoting growth, with tests conducted three times for each sample as the replication. Pure colonies were isolated via the four-quadrant streaking method. All samples exhibited successful growth on PDA media, with distinctive colony formations. EM primarily produced creamy, round bacterial colonies, while SMS and SMS + EM samples displayed fungal structures. Microscopic examination identified cocci-shaped bacteria in EM samples and yeast cells in SMS and SMS + EM samples. While this study focused on morphological identification, it does not provide precise species-level resolution and may overlook non-culturable organisms. Nonetheless, it presents a practical, low-cost approach for characterizing microbial communities in EM and SMS, offering foundational data for future research and applications in organic farming and soil enrichment.

Spent mushroom substrates can be utilized as organic fertilizer in agricultural production but may pose a health risk. Nitrification inhibitors dicyandiamide and 3,4‐dimethylpyrazole phosphate have been used to enhance fertilizer nitrogen utilization efficiency. However, the changes of soil abiotic properties, microbial activities, nitrogen cycling and human‐disease genes, and their comprehensive relationships after the spent mushroom substrate and nitrification inhibitor applications were still unknown. In this study, the spent mushroom substrate and nitrification inhibitor were applied into the agricultural soils at the rates of 2.5% (w/w) and 1.0% of nitrogen content in the spent mushroom substrate, respectively, and then lettuce was planted. Compared with the control, spent mushroom substrate application significantly increased the lettuce biomass, soil enzyme activities and chitinase, protease, nitric‐oxide reductase, nitrogenase, and urease gene abundances. However, the antibiotic resistance and human‐disease gene abundances were also significantly enhanced following the spent mushroom substrate application. Relative to spent mushroom substrate alone, the dicyandiamide application significantly decreased the soil pH and human‐disease gene abundances, although extra dicyandiamide and 3,4‐dimethylpyrazole phosphate enhanced 61.4% and 45.0% of dry biomass of aboveground lettuce. The human‐disease gene abundances were positively correlated with soil pH but were negatively correlated with the Acidobacteria and Streptomyces ratios in soils. Spent mushroom substrate application could generate double‐edged sword effects, and the health risk should be considered in the spent mushroom substrate applications. Extra dicyandiamide application could further promote crop growth while decrease the human‐disease risk from the spent mushroom substrate.