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Total C in biochar samples prepared using L. pallida and G. funicularis seaweeds at different temperatures. Error bars indicate standard deviation.
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Biochar has been reported as an efficient tool for carbon sequestration and soil quality improvement, though most research has evaluated the quality of biochar from terrestrial based materials. The study evaluated the macro; micro nutrients and heavy metal concentrations of biochar from seaweeds from Namibian coast. Seaweed species Laminaria pallid...
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... was interesting to observe that at a pyrolysis temperature of 400 °C biochar samples of G. funicularis and L. pallida resulted in the highest total C of 38.3% ± 0.31 and 26.1% ± 0.31, respectively. The lowest total C was observed at a pyrolysis temperature of 800 °C in biochar from both seaweed species ( Fig. 5 ). Across all pyrolysis temperatures, biochar from G. funicularis recorded the highest average total C of 33.3% ± 0.14 whilst L. pallida biochar had an average of 22.9% ± 0.14 representing 31.2% ...
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Due to their specific physicochemical, capillary, and porous properties, the cellulosic sorbents from macrophytes have a high number of possible uses. The number of studies of alternative sources of cellulose is nowadays increasing. One of the most interesting cellulose-containing components of brown algae biomass is protein-cellulose complexes (PC...
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... For instance, a seminal study on the characterization of BC derived from seven algae species did not evaluate the influence of pyrolysis parameters, still concluding that BCs could work as a soil ameliorant and improve soil carbon sequestration [4]. Nevertheless, others studied [15][16][17] the influence of pyrolysis temperature in the properties of algal BCs, focusing on the changes in BC yield, ash content, pH, electrical conductivity, elemental analysis and use for soil phosphate adsorption, implying that the pyrolysis temperature affected biochars' physicochemical properties [15]. In addition, BC from Cladophora glomerata was produced at different pyrolysis temperatures (300, 350, 400 and 450 °C) with emphasis on its suitability as a bio sorbent of toxic metals for wastewater treatment [16]. ...
... In addition, BC from Cladophora glomerata was produced at different pyrolysis temperatures (300, 350, 400 and 450 °C) with emphasis on its suitability as a bio sorbent of toxic metals for wastewater treatment [16]. Also, the influence of pyrolysis temperature in algal BCs and their benefits as organic nutrient sources have been addressed before [17]. Moreover, investigations into the use of algal biochar for soil improvement, produced at a single pyrolysis temperature, have been carried out on six commercially cultivated seaweed species [18]. ...
... The abovementioned information shows that algal-based biochars, derived from natural and cultivated species, exhibit a fast decomposition rate and high available N, P and K concentrations [12,17]. In addition, reviews on algal BC production and on the use of algae for bio-oil production, bioenergy and bio-syngas are available [13,19,20]. ...
Limited knowledge is available regarding biochar (BC) obtained from beach-cast seaweed, which needs to be characterized to better prospect its potential applications. Beach-cast seaweed BCs were produced at two temperatures (300 and 600 °C) and two residence times (1 and 3 h). First, an extensive characterization of feedstock and their derived BCs was performed. Then, an incubation experiment was conducted to investigate the potential of these BCs as ameliorants in two acidic soils, classified as Umbrisols. Proximate and elemental analyses suggested the presence of more stable C structures in BCs at 600 °C with a high C, fixed carbon (FC) and low H, O and volatile matter (VM); additionally, thermogravimetric graphics showed less weight loss. Some features from the raw material were present in biochars obtained at 300 °C but absent at 600 °C. Dissolved organic carbon was much lower in BCs pyrolyzed at 600 °C than at 300 °C, suggesting the higher aromaticity of the former, allowing more resistance to water extraction. The breakdown of proteinaceous soluble materials after pyrolysis was revealed by fluorescence. Residence time caused minor effects in biochar properties compared to temperature. The soil pH and macronutrient availability of the two studied soils increased after beach-cast seaweed biochar addition.
... Beach wrack, a diverse, complex, and highly variable resource, is fundamental for the sandy beach ecosystem, as it provides food and habitat for several species, also being responsible for coastal waters fertilisation (Villares et al., 2016). However, the accumulation of wrack along the coastline, which is natural phenomenon, is predicted to increase in some regions of the planet due to extreme climatic events, global warming, anthropogenic activities (i.e. industry and coastal development) and water enrichment with nutrients, posing a serious environmental problem (Chubarenko et al., 2021;Katakula et al., 2020;Milledge and Harvey, 2016;Robbe et al., 2021;Rudovica et al., 2021). Indeed, the overaccumulation of this biomass, which quickly starts to decompose, leads to the emission of gases with an unpleasant odour, which negatively impacts beach amenity (Chubarenko et al., 2021). ...
... A high nutrient content was observed when wrack was composted with other organic materials, as it was the case of a compost produced from green macroalgae (a mixture of Cladophora sp. and Enteromorpha), sawdust and quail manure for 120 days, which yielded a product with high levels of potassium (766 mg kg − 1 dw ), calcium (315 mg kg − 1 dw ), magnesium (285 mg kg − 1 dw ), phosphorous (213 mg kg − 1 dw ), iron (324 mg kg − 1 dw ) and sulphur (181 mg kg − 1 dw ) (Michalak et al., 2017). Another study focused on producing biochar, a product resulting from biomass pyrolysis, from two species of wrack-forming algae (Laminaria pallida and Gracilariopsis funicularis), found a high content of nitrogen (4.37%), phosphorous (6 g kg − 1 ) and potassium (185 g kg − 1 ) (Katakula et al., 2020). On the other hand, wrack presented a low carbon/nitrogen ratio (Illera-Vives et al., 2013;Michalak et al., 2017;Villares et al., 2016), characteristic from macroalgae, thus indicating that this material would undergo a rapid mineralisation process, when compared to other organic fertilisers (Illera-Vives et al., 2020). ...
... However, carbon/nitrogen ratio levels of wrack can be increased by composting it with carbon-rich materials, as it was previously reported (Illera-Vives et al., 2013;Madejón et al., 2022;Michalak et al., 2017). Since sodium is a highly abundant element in beach wrack (Katakula et al., 2020;Madejón et al., 2022;Villares et al., 2016), given its marine origin, its levels could limit wrack utilisation in soils due to salinisation. Additionally, and recognising the capacities of macroalgae to absorb potentially toxic elements, some authors proceeded with the metal quantification on macroalgae or in their by-products. ...
... Macroalgae is also a potential biomass source for biofuels, and major U.S. federal funding has been allocated to exploring this potential further (Chen et al. 2015;Laurens et al. 2020;Coleman et al. 2022). Seaweed processed into biochar or fertilizer may also assist in enhancing soil capacity for carbon sequestration (Katakula et al. 2020;Kholssi et al. 2022). ...
In 2022, The Nature Conservancy conducted a situation analysis to understand better the potential for restorative seaweed aquaculture development in Oregon, including the potential positive and negative impacts of the marine industry. This report focuses on seaweed aquaculture in the marine environment and explores basic questions concerning species options, high-potential locations and co-location opportunities for development, potential in-water production methods, market opportunities, supply chain analyses, ecological considerations, policy needs, and the landscape of current and potential partners.
... In another study, the incorporation of biochar made from corn cobs and wood enhanced the quality of soil as it supplied a more stable carbon source as well as essential plant nutrients during the production of maize (Kizito et al., 2019). Biochar as an amendment is quite interesting as it is rich in recalcitrant forms of carbon and contains elevated nutrient concentrations (Katakula et al., 2020). The use of biochar as an amendment of composting materials has the potential to increase organic matter content and reduce the bioavailability of heavy metals, whilst enhancing humification parameters and nutrient retention during vermicomposting (Were et al., 2019). ...
... Much of the research that has used biochar as an amendment has mainly used a material of terrestrial origin with no research having used marine biomass. Recently, Katakula et al. (2020) identified that biochar derived from seaweed species such as Laminaria pallida and Gracilariopsis funicularis pyrolysed at a temperature of 400 • C can generate nutrient-rich and carbon-rich biochar. Marine biomass derived-biochar can be an important source of amendment for organic fertilizers in hyper-arid countries such as Namibia. ...
... The optimum ratio of food waste and goat manure mixture of 50% food waste and 50% goat manure was used based on the results of Katakula et al. (2021). The seaweed biochar used in this study was identified from Katakula et al. (2020), and this was derived from G. ...
Vermicomposts are organic fertilizer sources that are being promoted; however, their concentrations of macronutrients such as NPK are very low. This study, therefore, evaluated the effects of amending goat manure–food waste mixture with biochar prepared from seaweed (Gracilariopsis funicularis) at 0% (control), 2, 4, 6, and 8% on vermicompost degradation and macronutrient release. After 10 weeks of vermicomposting, the highest pH of 9.06 was observed within the control, whilst the lowest was 8.7 in the 8% treatment. The electrical conductivity showed a positive relationship with the level of biochar incorporation with the highest of 16.5 mS/cm from the 8% treatment, whilst the lowest was within the control with 6 mS/cm. There were no significant differences between treatments on humification parameters; however, there were significant differences in the changes in a C/N ratio with the final C/N ratio of 14.4, 14.9, 16.7, 15.1, and 14.4 for the control, 2, 4, 6, and 8% treatments, respectively. A higher incorporation rate resulted in the higher concentration of potassium with a value of 32.3 g/kg at week 8. The final percentage change in Olsen P was 19, 14.2, 7.3, 4.1, and 3.0% for the 8%, 6%, control, 4%, and 2% treatments, respectively. An optimized level of 6% to 8% biochar incorporation ratio can be recommended. However, the incorporation of G. funicularis biochar does not seem to influence changes in the vermidegradation efficiency, though it can significantly improve the macronutrients such as P, K, and Mg concentrations as well as the macroelement concentrations.
... Overall, a 400 °C pyrolysis temperature was optimum for the best quality biochar in aspects of total carbon pH, and macro-elements. Gracilariopsi funicularis biochar displayed substantially higher nutrient contents and thus has excellent potential in improving soil quality (Katakula et al. 2020). Roberts et al. (2015) concluded that seaweed-derived biochar had high nitrogen (0.3-2.8%), phosphorus (0.5-6.60 g/kg), and potassium (5.1-119 g/kg) contents and exchangeable cations. ...
The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.
... Thus, other parameters need to be considered when optimizing the pyrolysis process. Katakula et al. investigated the possibility of using the beach-cast seaweed biochar as a fertilizer (Katakula et al., 2020). Sörbom evaluated biochar production from the pyrolysis of beach-cast seaweed through a life cycle assessment (Sörbom, 2020). ...
The blooming of beach-cast seaweed has caused environmental degradation in some coastal regions. Therefore, a proper treating and utilizing method of beach-cast seaweed is demanded. This study investigated the potential of producing bio-oil from pyrolysis of beach-cast seaweed and the effect of the ash-washing process. First, the raw and ash-washed beach-cast seaweeds (RS and WS) were prepared. Thereafter, thermogravimetric analysis (TG), bench-scale pyrolysis experiment, process simulation, and life cycle assessment (LCA) were conducted. The TG results showed that the activation energies of thermal decomposition of the main organic contents of RS and WS were 44.23 and 58.45 kJ/mol, respectively. Three peak temperatures of 400, 500, and 600°C were used in the bench-scale pyrolysis experiments of WS. The 600°C case yielded the most desirable gas and liquid products. The bench-scale pyrolysis experiment of RS was conducted at 600°C as well. Also, an LCA was conducted based on the simulation result of 600°C pyrolysis of WS. The further process simulation and LCA results show that compare to producing liquid biofuel and syngas, a process designed for electricity production is most favored. It was estimated that treating 1 ton of dry WS can result in a negative cumulative energy demand of -2.98 GJ and carbon emissions of -790.89 kg CO2 equivalence.
... In another study, the incorporation of biochar made from corn cobs and wood improved soil quality as it provided higher soil organic matter of and macronutrients during the production of maize (Kizito et al. 2019). Biochar as an amendment is quite interesting as it is rich in recalcitrant forms of carbon and contains elevated nutrient concentrations (Katakula et al. 2020). The use of biochar has potential to reduce the bioavailability of trace elements, increase organic matter content of composting feedstock, enhance the level of humi cation and increases nutrient retention during vermicomposting (Were et al. 2019). ...
... Much of the research that has used biochar as an amendment has mainly used material of terrestrial origin with no research having used marine biomass. In a recent study, Katakula et al. (2020) identi ed that biochar derived from seaweed species such as Laminaria pallida and Glacilariopsis funicularis pyrolysed at a temperature of 400 degrees Celsius can generate nutrient rich and carbon rich biochar. ...
... The optimum ratio of food waste and goat manure mixture of 50% food waste and 50% goat manure was used based on the results of Katakula et al. (2021). The seaweed biochar used in this study was identi ed from Katakula et al. (2020) and this was derived from G. funicularis which was pyrolysed at a temperature of 400 degrees C for 1 hr. Plastic buckets of 20 L capacity were used as vermi-reactors for the process of vermicomposting, and holes were drilled at the bottom and on the lid for gaseous exchange and leachate drainage . ...
Vermicomposts are organic fertilizer sources that are being promoted, however their concentration of macro nutrients such as (NPK) are very low. This study therefore evaluated the biochar from seaweed (Gracilariopsis funicularis) incorporated into a goat manure-food waste mixture at 0% (control); 2%; 4%; 6% and 8% on compost degradation and macro-nutrient release. After 10 weeks of vermicomposting the highest pH of 9.06 was observed within the control whilst the lowest was 8.7 in the 8% treatment. The electrical conductivity showed a positive relationship with the level of biochar incorporation with the highest of 16.5 mS/cm from the 8% treatment whilst the lowest was within the control with 6 mS/cm. There were no signi cant differences between treatments on humi cation parameters, however there were signi cant differences on the changes of C/N ratio with the nal C/N ratio of 14.4; 14.9; 16.7; 15.1 and 14.4 for the control; 2%; 4%; 6%; and 8% treatments respectively. Higher incorporation rate resulted in the higher concentration of potassium with a value of 32.3 g/kg at week 8. The nal percentage change in Olsen P was 19%: 14.2%; 7.3%; 4.1% and 3.0% for the 8%; 6%; control; 4%; and 2% treatments, respectively. An optimized level of 6 to 8 % biochar incorporation ratio can be recommended. However, incorporation of G. funicularis biochar does not seem to in uence changes in the vermi degradation e ciency, though it can signi cantly improve the macro nutrients like P, K and Mg concentrations as well as the macro element concentrations.
... Furthermore, chemical properties, such as contaminant fixation and carbon sequestration, are also improved [102]. At the same time, biochar leads to changes in soil microbial abundance and diversity [96,99,101,103]. It is currently being assessed as a better soil amendment compared to other organic materials like animal manure to improve soil quality and reduce greenhouse gas emissions [79,96,103]. ...
... At the same time, biochar leads to changes in soil microbial abundance and diversity [96,99,101,103]. It is currently being assessed as a better soil amendment compared to other organic materials like animal manure to improve soil quality and reduce greenhouse gas emissions [79,96,103]. Production and application of biochar are feasible in terms of raw material as it mostly uses waste materials and does not involve any sophisticated process. ...
This paper reviews relevant facts and statistics about the benefits and impacts of the growing use of chemical fertilizer with a focus on soil fertility, crop productivity, and alternative sources of biofertilizers. Agriculture in Ethiopia is the main source of the economy, and it is the key contributor of the export value and provider of raw materials to processing industries. However, Ethiopian agronomical production is characterized by low output, lack of infrastructure, and low level of technology and is enormously dependent on rainfall availability. In Ethiopia, soil fertility reduction is evolving as a serious contest causing low crop yields, and research findings reported that, at the country level, nutrient balance indicated a depletion rate of 122 kg N ha−1 yr−1, 13 kg P ha−1 yr−1, and 82 kg K ha−1 yr−1. To control soil fertility depletion, primarily fertilizers are used as the source of essential plant nutrients. In Ethiopia, the use of chemical fertilizers to increase crop production was low relative to other developing countries; however, now, it is steadily increasing. Urea and diammonium phosphate are common practices for maintaining soil fertility. Chemical fertilizer consumption increased from 12 kg/ha in 1996 to 36.2 kg/ha in 2018. The main cereals’ production increased from 16.5 quintal/ha in 2009 to 23.94 quintal/ha in 2018.
... From the total of 138 scientific records about beach-cast seaweeds, we categorized the study approach into 13 levels: animal feed, bioactivity, bioenergy, biosorption of metals, carrageenan, chemical composition, ecology, fertilizer, human food, occurrence, physiology, review, and taxonomy and abundance (Fig. 4). Of the 101 studies registered in other countries than Brazil, four were related to animal feed [32][33][34][35], five to bioactivity [36][37][38][39][40], nine to bioenergy [41][42][43][44][45][46][47][48][49], two to biosorption of metals [50][51], 11 to chemical composition [52][53][54][55][56][57][58][59][60][61][62], 50 to ecology [9,23,26,28,, seven to fertilizer [109][110][111][112][113][114][115], two to human food [116,117], seven to reviews [27,[29][30][31][118][119][120] and four to taxonomy and abundance [121][122][123][124] (Fig. 4A and Table 2). Some of the literature address more than one subject of our categories, the oldest available online literature was found in 1970. ...
... To reduce the accumulation of cadmium in European soils, it was suggested to regulate the maximum permissible cadmium concentration per kg of phosphorus in all mineral fertilizers and monitoring the cadmium concentrations from the beach-cast algae [114]. Recently [115] showed that beach-cast seaweeds have high nutrient concentrations and therefore have great potential for improving soil quality. ...
There is an extensive demand for new sources of natural products with biofunctional properties, in which macroalgae can be relevant components to encounter this need. Nowadays, there are no commercial-scale alga crops to supply the biomass market for exploitation in some countries. The high availability of beach-cast seaweed biomass with potential application makes them an attractive and sustainable alternative to satisfy this demand. Currently, the excess of beach-cast seaweeds on the beaches causes an environmental problem, as its decomposition affects the use of the beach and keeps tourists and bathers away, affecting financial income in the region. Considering this negative impact on the environment and the possibility of using this biological feedstock, some countries establish quotas that make it possible to reduce the volume and maintain the stock in the environment. This review aims to gather information on studies related to beach-cast marine algae in the world and Brazil, addressing ecological, economic, and potential applications. The exploitation of beach-cast algae can be a socio-economic and environmentally sustainable solution, since it reduces financial costs, generates an alternative income for the local population, and limits the impact of extraction on natural beds of macroalgae, threatened by over-exploitation. The relevance of this material is shown by gathering information on the prospecting of the biomass given the development of technology for algae matrices with a focus on the development of functional products and sustainable use of unexplored biomass considered as waste. The use of beach-cast seaweeds as a resource is an eco-efficient alternative that favors society and the environment, generating usable resources that were previously seen as limited and trash. In addition to encouraging pollution mitigation in coastal regions and socioeconomic development sustainably. The data presented in this review will significantly contribute, increasing the knowledge of beach-cast seaweeds worldwide and their potential uses.
... In another study, the incorporation of biochar made from corn cobs and wood enhance the quality of soil as it supplied more stable carbon source as well as essential plant nutrients during the production of maize (Kizito et al. 2019). Biochar as an amendment is quite interesting as it is rich in recalcitrant forms of carbon and contains elevated nutrient concentrations (Katakula et al. 2020). The use of biochar as an amendment of composting materials has potential to increase organic matter content and reduce the bioavailability of the heavy metals, whilst enhancing humi cation parameters and nutrient retention during vermicomposting (Were et al. 2019). ...
... Much of the research that has used biochar as an amendment has mainly used material of terrestrial origin with no research having used marine biomass. Recently, Katakula et al. (2020) identi ed that biochar derived from seaweed species such as Laminaria pallida and Glacilariopsis funicularis pyrolysed at a temperature of 400 degrees Celsius can generate nutrient rich and carbon rich biochar. Marine biomass derived biochar can be an important source of amendment for organic fertilizers in hyper arid countries such as Namibia. ...
... The optimum ratio of food waste and goat manure mixture of 50% food waste and 50% goat manure was used based on the results of Katakula et al. (2021). The seaweed biochar used in this study was identi ed from Katakula et al. (2020) and this was derived from G. funicularis which was pyrolysed at a temperature of 400 degrees Celsius for 1 hr. Vermi-reactors made from 20 L plastic buckets were used as outlined by Katakula et al. (2021). ...
Vermicomposts are organic fertilizer sources that are being promoted, however their concentration of macro nutrients such as (NPK) are very low. This study therefore evaluated the biochar from seaweed ( Gracilariopsis funicularis ) incorporated into a goat manure-food waste mixture at 0% (control); 2%; 4%; 6% and 8% on compost degradation and macro-nutrient release. After 10 weeks of vermicomposting the highest pH of 9.06 was observed within the control whilst the lowest was 8.7 in the 8% treatment. The electrical conductivity showed a positive relationship with the level of biochar incorporation with the highest of 16.5 mS/cm from the 8% treatment whilst the lowest was within the control with 6 mS/cm. There were no significant differences between treatments on humification parameters, however there were significant differences on the changes of C/N ratio with the final C/N ratio of 14.4; 14.9; 16.7; 15.1 and 14.4 for the control; 2%; 4%; 6%; and 8% treatments respectively. Higher incorporation rate resulted in the higher concentration of potassium with a value of 32.3 g/kg at week 8. The final percentage change in Olsen P was 19%: 14.2%; 7.3%; 4.1% and 3.0% for the 8%; 6%; control; 4%; and 2% treatments, respectively. An optimized level of 6 to 8 % biochar incorporation ratio can be recommended. However, incorporation of G. funicularis biochar does not seem to influence changes in the vermi degradation efficiency, though it can significantly improve the macro nutrients like P, K and Mg concentrations as well as the macro element concentrations.
