Equilibrium, kinetic and thermodynamic studies of biosorption of zinc ions from industrial wastewater using derived composite biosorbents from walnut shell

The biosorption process of Zn (II) ions in industrial wastewater was investigated using derived composite biosorbents from walnut and snail shells. Composite adsorbents were produced by activating walnut shell carbon (WSC) with phosphoric acid to obtain acid-treated walnut shell carbon (AWSC) and WSC and AWSC were independently impregnated on chitosan to produce walnut shell carbon impregnated on chitosan (WSCC) and acid-treated walnut shell carbon impregnated on chitosan (AWSCC) respectively. The removal efficiencies of Zn (II) ions from synthetic wastewater using the prepared adsorbents were determined. The effects of operational parameters on Zn (II) ions adsorption were investigated. The adsorption data of Zn (II) ions were analysed using Langmuir, Freundlich and Temkin isotherms. The Langmuir isotherm fitted the adsorption data excellently for the derived composite biosorbents, giving an indication of monolayer coverage on the derived composite biosorbents and the determination coefficients were close to unity. Also, the maximum adsorption capacities of 3.1104, 3.8052, 16.4474 and 17.6991 mg/g were obtained for WSC, AWSC, WSCC and AWSCC at pH=5, 1 g of adsorbent dosage, Zn (II) ions initial concentration of 30 mg/L, contact time of 2 h, agitation speed of 150 rpm, particle size of 60 BSS and temperature of 30°C. The kinetic modelling of Zn (II) ions adsorption showed that pseudo second-order kinetic model gave the best fit amongst the investigated kinetic models. The adsorption of Zn (II) ions on the prepared adsorbents was filmdiffusion controlled. The experimental results of this study showed that acid-treated walnut shell carbon impregnated on chitosan has the potential to be applied as alternative efficient low-cost biosorbent in the remediation of heavy metal contamination in wastewater. The thermodynamic parameters indicated that the adsorption of Zn (II) ions on the derived composite biosorbents was exothermic, endogonic, favourable, non-spontaneous with changes in enthalpy ( H , negative), entropy [ S , nearly zero (though negative)], and Gibbs free energy (G, positive), for all the prepared adsorbents

Harnessing Opportunities for Informed Investments in the Sorghum Commodity Value Chain in Tanzania: A Business Case

This study was conducted among sorghum farmers, focus groups, seed producers and extension officers in 10 districts of Tanzania to map out business opportunities along the sorghum value chain. Results obtained demonstrated that socio-economic factors such as number of years spent in school, group membership, availability of free seeds, market accessibility and seed accessibility influenced the adoption of improved varieties among sorghum farmers. Improved sorghum seeds reflected the profitability from positive gross benefits obtained among sorghum farmers and seed producers. The general adoption rate among sorghum farmers was low (39.0%), with variety NACO Mtama 1 having the highest adoption rate among farmers (17.0%). Among traders, a majority were large off-takers (79.0%). These off-takers experienced issues such as quality (71.4%), quantity (15.9%), lack of market information (7.9%), unreliable markets (36.3%), low grain quality (24.8%) and high tax levies (10.6%). Further, financial constraints and poor linkages among stakeholders were some inefficiencies in the sorghum value chain. The study recommends greater accessibility to improved sorghum seeds as well as reliable policies that enable processes for sorghum stakeholders along the sorghum value chain

Legume breeding and seed systems for improved livelihoods and impact

The Tropical Legumes III project aims to reduce food insecurity in drought-prone areas of Sub Saharan Africa (SSA) and South Asia (SA), through improved productivity and production of four major grain legumes – chickpea, common bean, cowpea and groundnut. This is being sone by conducting research under three complementary research and delivery pillars: support for the development and release of farmer-preferred varieties; strengthening of the legume breeding capacity of partner CGIAR centers (ICRISAT, IITA and CIAT), and national partners Burkina Faso, Ghana, Mali, Nigeria, Ethiopia, Tanzania and Uganda; and establishment of sustainable seed delivery systems that service the needs of small-holderfarmers. Significant achievements have been recorded. Breeding program assessments have been completed in all countries and improvement plans developed for execution. New seed varieties (163) have been released and are fast replacing the old ruling seed varieties in all target countries. Thirty seven national partners were trained at MSc and PhD levels. As a result of the enhanced skills and knowledge of seed value chain actors, seed production significantly increased by 221% (from 139,048 to 446,359 tons) in seven years. Since 2007, improved varieties have been adopted on at least 2 million hectares and more than $448 million has been generated from the project funding and nearly$976 million from the project and investment partners. For each dollar invested, the project generated $9 with direct project investment or$20 with partnership’s investment, and again $20 when using adoption rate based estimate. These achievements and implementation challenges will be discussed

Legume breeding and seed systems for improved livelihoods and impact

The Tropical Legumes III project aims to reduce food insecurity in drought-prone areas of Sub Saharan Africa (SSA) and South Asia (SA), through improved productivity and production of four major grain legumes – chickpea, common bean, cowpea and groundnut. This is being sone by conducting research under three complementary research and delivery pillars: support for the development and release of farmer-preferred varieties; strengthening of the legume breeding capacity of partner CGIAR centers (ICRISAT, IITA and CIAT), and national partners Burkina Faso, Ghana, Mali, Nigeria, Ethiopia, Tanzania and Uganda; and establishment of sustainable seed delivery systems that service the needs of small-holderfarmers. Significant achievements have been recorded. Breeding program assessments have been completed in all countries and improvement plans developed for execution. New seed varieties (163) have been released and are fast replacing the old ruling seed varieties in all target countries. Thirty seven national partners were trained at MSc and PhD levels. As a result of the enhanced skills and knowledge of seed value chain actors, seed production significantly increased by 221% (from 139,048 to 446,359 tons) in seven years. Since 2007, improved varieties have been adopted on at least 2 million hectares and more than $448 million has been generated from the project funding and nearly$976 million from the project and investment partners. For each dollar invested, the project generated $9 with direct project investment or$20 with partnership’s investment, and again $20 when using adoption rate based estimate. These achievements and implementation challenges will be discussed