Removal of heavy metal ions from aqueous solution using rice husks-based adsorbents

This study reports on the preparation and characterization of rice husks-based adsorbents and their application in the removal of heavy metal ions from aqueous solution. Three different adsorbents were developed: rice husks ash (RHA), rice husks ash-derived silica (RHS) and triaminopropyl-silica hybrid (TSH-R). The prepared materials were characterized by acid titration, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) spectroscopy and nitrogen physisorption analysis. Results from the ATR-FTIR analysis indicated that pure silica was obtained from RHA and that after surface modification the triaminopropyl group was successfully attached onto the silica framework with a loading of 2.15 mmol per g silica. The RHA, RHS, TSH-R had average particle sizes of 336.8, 296.4 and 1054.1 nm and BET surface areas of 17.8, 20.2 and 5.7 m2/g, in the same order. Adsorption studies of Ni2+, Zn2+, Pb2+, Cu2+ and Co2+ ions showed that RHA and TSH-R were good adsorbents with an average maximum adsorption of 99 and 95 % for RHA and TSH-R, respectively when 1.0 g of adsorbent and initial metal ions concentration of 21 - 27 mg/L at pH 4 were employed. Both Langmuir and Freundlich isotherms indicated that the adsorption was favorable.Keywords: Triaminopropyl-silica hybrids, rice husks ash, rice husks silica, adsorptio

Performimg Education: The Utopian Potential of Creative Peer-to-peer Sexual Health Education for Queer Youth

The Independent Studies program closed in 2016. This thesis was one of 25 accepted by Library for long-term preservation and presentation in UWSpace.In this cultural moment, young queers are struggling to imagine themselves and find community. A significant component of enabling a youth's self-discovery is providing access to inclusive and culturally-relevant education about their bodies, especially as it relates to sexual health. Current models of instruction are limited. Institutional learning environments may rely on materials that are overtly or subtly homophobic (for example, speaking only of heterosexual relationships outside of the small section or chapter on other forms of sexual orientation). If a youth is lucky enough to encounter materials that strive to be more inclusive, the communication method may be dry and purely factual, leaving the youth to attempt to translate useful information into their daily life. This project addresses the gap in sexual health education for queer youth. I argue for the potential of using disidentificatory performance as a medium through which to build a self-sufficient commons for young queer people. In order to first identify the markers of this method of communication, I draw upon the work of Jose Esteban Munoz, a queer theorist and performance studies scholar. I conducted a critical content analysis of the fifth episode of the online video series called Heavy Petting and considered whether or not it could be considered an example of disidentificatory performance used for sexual health education. In my analysis of Heavy Petting, four themes arose, each of which related to things that are needed in order for a young queer commons to be self-sufficient: (1) tools for queering toxic tropes; (2) communication methods that allow for dissensus; (3) stylish politics grounded in a subversive aesthetic; and (4) role models and educators who will help create an intimate queerworld, in the words of Munoz. The results of my findings indicate that the Heavy Petting video is an example of disidentificatory performance, in that it satisfies the three criteria that I name as constitutive of the genre. This suggests that such peer-to-peer educational projects do indeed hold the potential to support commons building among young queer people

A genome-wide data assessment of the African lion (Panthera leo) population genetic structure and diversity in Tanzania

The African lion (Panthera leo), listed as a vulnerable species on the IUCN Red List of Threatened Species (Appendix II of CITES), is mainly impacted by indiscriminate killing and prey base depletion. Additionally, habitat loss by land degradation and conversion has led to the isolation of some subpopulations, potentially decreasing gene flow and increasing inbreeding depression risks. Genetic drift resulting from weakened connectivity between strongholds can affect the genetic health of the species. In the present study, we investigated the evolutionary history of the species at different spatiotemporal scales. Therefore, the mitochondrial cytochrome b gene (N = 128), 11 microsatellites (N = 103) and 9,103 SNPs (N = 66) were investigated in the present study, including a large sampling from Tanzania, which hosts the largest lion population among all African lion range countries. Our results add support that the species is structured into two lineages at the continental scale (West-Central vs East-Southern), underlining the importance of reviewing the taxonomic status of the African lion. Moreover, SNPs led to the identification of three lion clusters in Tanzania, whose geographical distributions are in the northern, southern and western regions. Furthermore, Tanzanian lion populations were shown to display good levels of genetic diversity with limited signs of inbreeding. However, their population sizes seem to have gradually decreased in recent decades. The highlighted Tanzanian African lion population genetic differentiation appears to have resulted from the combined effects of anthropogenic pressure and environmental/climatic factors, as further discussed

Valorization of rice husk silica waste:Organo-amine functionalized castor oil templated mesoporous silicas for biofuels synthesis

Rice husk is a rich source of waste silica which has potential for application in the preparation of porous materials for use as catalyst supports or sorbents. Here we report on the synthesis of rice husk silica (RHS) and mesoporous templated rice husk silica (MT-RHS) using sodium silicate, obtained from rice husk ash, and castor oil as a pore directing agent. The resulting silicas were functionalized with 3-aminopropyltriethoxysilane (APTS) or 3-diethylaminopropyltrimethoxysilane (DEPA), and their catalytic activity evaluated in the transesterification of model C4–C12 triglycerides (TAG) to their corresponding fatty acid methyl esters, of relevance to biodiesel synthesis. Castor oil templating enhances the surface area of rice husk silica, and introduces uniform 4 nm mesopores, albeit as a disordered pore network. Post-synthetic grafting of silica by APTS or DEPA resulted in base site loadings of 0.5 and 0.8 mmolg−1 respectively on RHS and MT-RHS. Turnover frequencies of amine-functionalized MT-RHS were 45–65% greater than those of their amine-functionalized RHS counterparts for tributyrin transesterification. Switching from a primary (APTS) to tertiary (DEPA) amine increased activity three-fold, delivering 80% tributyrin conversion to methyl butyrate in 6 h. DEPA-MT-RHS was effective for the transesterification of C8 and C12 triglycerides, with methyl caproate and methyl laurate selectivities of 93% and 71% respectively in 24 h

Carbon stocks potential in regenerating trees of the tropical coastal forest ecosystems

Estimation of carbon in the regenerating tropical coastal forest is needed to support conservation and forest monitoring strategies. This chapter presents the determined carbon stocks in regenerating species across forest sites subjected to deforestation because of crop-farming and livestock grazing. The study used thirty-three independent measurements of tree carbon stocks from thirty-three tree families found in the coastal zone of Tanzania. The vegetation was inventoried using a floristic survey of the woody component across intact, crop agriculture and livestock disturbed land-use sites. The biomass was then estimated by employing the existing allometric equations for tropical forests. Thereafter, the above-ground stored carbon was quantified on the sampled tree species found in each land uses. The tree varied (p ≤ .05) in carbon stock across species and land uses. The average carbon (Kg/ha) stored in the regenerated adult trees was 1200 in IFS, 600 in ADS, 400 in LDS. Saplings had 0.43 in LDS, 0.07 in ADS and 0.01 in IFS. Also, seedlings showed an average of 0.41 in IFS, 0.22 in ADS and 0.05 in LDS. It shows that crop-agriculture highly affects the regeneration potential of trees, biomass accumulation and carbon stock than livestock grazing. To restore the carbon storage potential of coastal tropical forests, crop-agriculture must be discouraged, while livestock grazing can be integrated into forest management. Indeed, further studies are required to gauge the integration levels of any anthropogenic activities, so that the natural capacity of coastal tropical forests to regenerate and stock carbon is not comprised further

Space Research in Africa: Challenges and Opportunities

Africa has lost its glory as the pioneer of space research as evidenced by the ancient library of Alexandria in Egypt that housed the first space research centre more than two thousand years ago. Cave paintings in Olduvai Gorge in present day Tanzania showed how the first humans communicated millions of years ago. Early Africans used drum beats to alert of an impending danger or of festivities. The discovery of papyrus the material used as writing paper and the invention of words that make the alphabet all originated in Ancient Egypt. All of these examples show that at a certain stage in history, Africa was a leader in science and technology (Shibanda & Isabel, 2000). However in the 21st Century, Africa has lagged behind technologically compared to all the other continents. Space research and deployment of supporting technologies including remote sensing and Geospatial Information Systems (GIS) remain fundamental to bridge the technological gap between Africa and the rest of the world hence solving some of Africa’s challenges. This study analyses the challenges and opportunities that African countries face in harnessing space technologies to be used in natural disaster management, disease prevention, land use, agricultural productivity improvements and even in conflict resolution.Key Words: Space Research, Geospatial Information Systems, Remote sensing, Afric

Canonical correlation analysis across vegetation and soil properties of the disturbed and undisturbed coastal forest ecosystems

Advances in Research, 2019; 18(3): 1-14This study presents comparative initial information about canonical correlation across forest stand parameters, diversity indices and soil properties in undisturbed forest sites (IFS), agriculture disturbed sites (ADS) and livestock disturbed sites (DGS). Data were collected from Uzigua Forest Reserve in Tanzania. Forty- seven sample plots of 25 m × 25 m were randomly established on IFS, ADS and DGS from which tree inventory data and 141 soil samples were drawn. Data were subjected into Canoco windows 4.5 software for multivariate analyses and comparisons across IFS, ADS and DGS. The correlation of tree stand parameters (TSP) and soil physical properties (SPP) were F=1.207, p=0.242 in IFS, F=2.400, p=0.012 in ADS and F=0.529, p=0.938 in DGS. For soluble bases and TSP were F=2.448, p=0.018 in IFS, F=0.687, p=0.790 in ADS and F=0.743, p=0.808 in DGS. Carbon, nitrogen and potassium (CNP) and TSP were F=0.816, p=0.572 in IFS, F=0.687, p=0.790 in ADS and F=0.070, p=0.020 in DGS. The SPP and Shannon indices had F=1.103,p<0.388 in IFS, F=0.520, p=0.714 in ADS and F=0.932, p=0.444 in DGS. The SPP and Independent Value Index (IVI) were F=0.042, p=0.996 in IFS, F=0.819, p=0.620 in ADS and F=0.633, p=0.724 in DGS. Soluble bases and equitability were F=0.119, p=0.968 in IFS, F=0.001, p=0.001 in ADS and F=0.011, p=0.001 in DGS. The CNP and IVI had F=4.246, p=0.014 in IFS, F=2.729, p=0.018 in ADS and F=2.007, p=0.060 in DGS. The mean higher canonical correlation in the non-disturbed sites indicates that crop-agriculture and livestock grazing affect the interplays between forest vegetation and soil properties. Therefore, human activity disturbs the structure and soil properties

Soluble bases and cec variation across Undisturbed and disturbed coastal forests in Tanzania

Understanding of different levels of soil calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), cation exchange capacity (CEC), and percentage base saturation (BS), is important in the management of forest ecosystems. However, there is limited documentation on the status of these elements in the undisturbed forest sites (CFS) crop-agriculture (ADS) and livestock grazing (DGS) disturbances in the tropical coastal forests. This chapter attempts to address this deficit by presenting soil fertility based on exchangeable bases’ status and variations across undisturbed forest sites (used as a control), crop-agriculture and livestock disturbed sites in the coastal zone of Tanzania. The chapter aims to add knowledge on the management of tropical coastal forests. Indeed, this chapter shows that crop-agriculture and livestock grazing disturb soil chemical properties in tropical coastal forests. Therefore, it is essential to protect undisturbed forest while putting more efforts to restore the disturbed sites for sustainable forest management along the coastal areas

Hydrogeochemistry of arsenic, fluoride, and other trace elements in groundwater in northern Tanzania : Occurrence, distribution, and impacts on drinking water quality

The occurrence of arsenic (As), fluoride (F-), and other trace elements (TEs) with potential toxicity in groundwater is a global environmental concern. According to the National water resource mapping database, about 76 % of the drinking water supply in Tanzania is abstracted from groundwater sources. In northern Tanzania groundwater accounts for more than 80 % of the drinking water supply. Albeit the importance of groundwater in northern Tanzania, its quality concerning geogenic contaminants is not optimally understood. The present study focused on estimating the groundwater quality using analytical, geochemical modeling, statistical, and GIS techniques which were carried out to better understand the chemical quality of groundwater in the framework of safe drinking water supply in Tanzania. Fluoride was established as the principal geogenic groundwater contaminant in northern Tanzania, particularly in the Pangani and internal drainage basins, parts of the East Africa Rift Valley (EARV) system. About 8 % and 57.6 % of the water samples collected from Geita and Sanya alluvial plain have indicated F- concentration above the WHO guidelines value (1.5 mg/L) for drinking water. The high F- concentration in groundwater originates from F- rich minerals and ash deposits from the granitic and alkaline volcanic parent rocks. The consumption of elevated concentrations of F- in groundwater has been responsible for dental, skeletal, and crippling fluorosis. In the Lake Victoria basin (LVB) goldfields, As was reported to be the main geogenic contaminant of health concern. The concentration of As in 50 % and 82 % of the groundwater samples from Tarime and Geita respectively exceeded the WHO guidelines (10 µg/L). The high concentration of As in groundwater from the LVB was highly associated with natural geochemical processes as well as gold mining activities. Results from geochemical modeling revealed that As mobilization was influenced by oxidative and/or reductive dissolution of As-containing sulfide and iron minerals, respectively from the parent rocks. The concentrations of other TEs (aluminum, chromium, cobalt, copper, iron, manganese, nickel, and zinc) were observed below the WHO drinking water guideline. The spatial variability of As and F- concentration from drinking groundwater sources was associated with the different groundwater levels, screened depths, and contact time of groundwater interaction with the As and F-- containing rock minerals in the aquifers. Furthermore, irrigation water sourced from the F- contaminated boreholes poses risks of contaminating the shallow aquifers that are easily accessible for human and domestic animals’ consumption. The current WHO recommended guidelines of 10 µg As/L and 1.5 mg F-/L intake for humans are open to further epidemiological scrutiny, especially considering chronic/long-term exposure in the region. The present study highlights the need for large-scale hydrogeochemical and human health risk investigations concerning geogenic contaminants in the region. The findings contribute to the local, regional, and global initiatives toward sustainable exploitation of groundwater resources in conformity with the Sustainable Development Goal (SDG) 6 for universal access to safe water and sanitation for all.Förekomsten av arsenik (As), fluorid (F-) och andra spårämnen (TE) med potentiell toxicitet i grundvattnet är ett globalt miljöproblem. Enligt den nationella kartläggningsdatabasen för vattenresurser kommer omkring 76 % av dricksvattenförsörjningen i Tanzania från grundvattenkällor. I norra Tanzania står grundvattnet för mer än 80 % av dricksvattenförsörjningen. Även om grundvattnets stora betydelse i norra Tanzania, grundvattenkvalitet med avseende på geogena föroreningar är inte optimalt förstått. Denna studie fokuserade på att uppskatta grundvattenkvaliteten med hjälp av analytiska, geokemiska modellerings-, statistiska och GIS-teknik som utfördes för att belysa grundvattnets kemiska kvalitet för att säkerställa dricksvattenförsörjning i Tanzania. Fluor etablerades som den främsta geogena grundvattenföroreningen i norra Tanzania, särskilt i avrinningsområden Pangani och Internal Drainage Basin, delar av Östafrikanska gravsänkesystemet (East Africa Rift Valley-system, EARV). Cirka 8 % och 57.6 % av vattenproverna från Geita och Sanya alluvial slätt har visat F- koncentration över WHO:s riktlinjer (1.5 mg/L) för dricksvatten. Den höga F- koncentrationen i grundvattnet härrör från F-rika mineraler och askavlagringar från de granitiska och alkaliska vulkaniska moderbergarterna. Konsumtionen av förhöjda koncentrationer av F- i grundvatten har orsakat omfattande tand-, skelett- och förlamande fluoros bland lokala befolkning. I guldfälten i Lake Victoria Basin (LVB) rapporterades As som den främsta forekommande geogena föroreningen med konsekvent hälsoproblem bland befolkning i området. Arsenik koncentrationen i 50 % och 82 % av grundvattenproverna från Tarime respektiv Geita översteg WHO:s riktlinjer (10 µg/L). Den höga koncentrationen av As i grundvattnet från LVB var starkt förknippad med naturliga geokemiska processer såväl som guldbrytningsaktiviteter. Resultat från geokemisk modellering visade att As-mobilisering påverkades av oxidativ och/eller reduktiv upplösning av As-innehållande sulfidmineraler respektive As-innehållande järnmineraler från moderbergarterna. Koncentration av andra spårämnen så som aluminium, krom, kobolt, koppar, järn, mangan, nickel och zink var under WHO:s riktlinjer för dricksvatten. Den rumsliga variationen av As och F- koncentrationen från dricksvattentäkter var relaterade till de olika grundvattennivåerna, djupet till brunnskärm och kontakttid för grundvattnets interaktion med de As och F-innehållande mineralerna i berg under grundvattenflödet. Dessutom bevattningsvatten från de F- förorenade grundvatten som används från borrade brunnar utgör risker för att förorena de grunda akvifererna som är lättillgängliga för konsumtion av människor och husdjur. De nuvarande WHO rekommenderade riktlinjerna för 10 µg As/L och 1.5 mg F-/L intag för människor är öppna för ytterligare epidemiologisk granskning, särskilt med tanke på kronisk/långvarig exponering i regionen. Den föreliggande studien belyser behovet av storskaliga utredningar för hydrogeokemiska och mänskliga hälsorisker när det gäller geogena föroreningar i regionen. Resultaten bidrar till de lokala, regionala och globala initiativen mot hållbart utnyttjande av grundvattenresurser i enlighet med Sustainable Development Goal (SDG) 6 för universell tillgång till rent vatten och sanitet för alla.Utokeaji wa aseniki (As), floride (F- ), na elementi nyingine (TEs) zenye sumukwenye maji yaliyopo ardhini ni suala mtambuka la kimazingira duniani. Kwamujibu wa kanzidata ya taifa ya upatikanaji wa rasilimali maji, takribani 76% yamaji ya kunywa yanayosambazwa nchini Tanzania hupatikana kwenye vyanzovya maji yaliyopo ardhini. Katika upande wa kaskazini mwa Tanzania majiyaliyopo ardhini hutumika kwa zaidi ya 80% kwa ajili ya kunywa. Licha yaumuhimu wa maji hayo kaskazini mwa Tanzania, ubora wake kuhusiana nauchafu wa kijiojeniki bado haujafahamika vizuri. Utafiti huu ulijikita kukadiriaubora wa maji yaliyopo ardhini kwa kutumia uchambuzi, modeli ya jiokemikali,kitakwimu, na Mifumo ya Taarifa za Kijiografia (GIS) ili kuelewa zaidi ubora wakikemikali wa maji yaliyopo ardhini katika kiunzi cha usambazaji wa maji yakunywa nchini Tanzania. Floridi iliripotiwa kama kichafuzi kikuu cha kijiojenikicha maji yaliyopo ardhini kaskazini mwa Tanzania hususani katika bonde laPangani, ambayo ni sehemu ya ukanda wa bonde la ufa la Afrika Mashariki.Takribani 8% na 57.6% ya sampuli za maji yaliyokusanywa Geita na kwenyeuwanda wa aluvia ya Sanya yameonesha ukolezi wa F- , zaidi ya kipimo chamwongozo wa shirika la afya duniani, (WHO) ambacho ni 1.5mg/L kwa maji yakunywa. Ukolezi mkubwa wa F- katika maji yaliyopo ardhini huanzia kwenyemadini yenye F- nyingi na tope la umajivu kutoka kwenye miamba mikuu yakivolkano ya graniti na alikali. Matumizi ya maji yaliyopo ardhini yenye kiwangokikubwa cha F- yamechangia udhoofu wa meno na mifupa. Katika migodi yadhahabu kwenye Bonde la Ziwa Victoria (LVB), As iliripotiwa kama kichafuzikikuu cha kijiojeniki cha masuala ya kiafya. Ukolezi wa As kwa 50% na 82%katika sampuli za maji yaliyopo ardhini kutoka Tarime na Geita mtawalia zilizid imwongozo wa WHO (10 μg/L). Kiwango kikubwa cha As kwenye maji yaliyopoardhini kutoka LVB kilihusishwa sana na michakato asilia ya kijiokemikalipamoja na shughuli za uchimbaji wa dhahabu. Matokeo ya modeli ya jiokemikaliyamebainisha kuwa ujitokezaji wa As ulichochewa na uoksidishaji na/auuyeyukaji wa taratibu wa madini ya salfidi na chuma mtawalia yenye As kutokakwenye miamba mikuu. Elementi nyingine (alminiamu, kromiamu, kobalti,shaba, chuma, manganizi, nikeli na zinki zilionekana kuwa chini ya kiwangokilichopendekezwa katika muongozo wa maji ya kunywa uliotolewa na WHO.Ubadilikajibadilikaji wa kimazingira wa ukolezi wa As na F- kutoka kwenyevyanzo vya maji ya kunywa kutoka ardhini ilihusianishwa na ngazi mbalimbali zamaji yaliyopo ardhini, vina na muda wa kuchanganya maji yaliyopo ardhini namiamba ya madini ya As na F- kwenye vyanzo vya maji. Aidha, umwagiliaji wamaji yaliyotoka kwenye visima vilivyochafuliwa na F- huweka uwezekano wakuvichafua vyanzo vya maji vyenye vina vifupi ambavyo hufikiwa kirahisikwenye shughuli za kibinadamu na matumizi ya nyumbani. Mapendekezo ya sasaya mwongozo wa WHO ya 10 μg As/L na 1.5 mg F- /L kwa ajili ya matumizi yabinadamu yanahitaji tafiti za kitabibu zaidi, hasa kwa kuzingatia matumizi yamuda mrefu ya maji ya kunywa. Utafiti huu unadokeza mahitaji makubwa yakuchunguza madhara ya haidrojiokemikali pamoja na afya za binadamu kuhusuuchafu wa kijiojeniki katika eneo husika. Matokeo ya utafiti huu yanachangiakwenye jitihada za kitaifa, kikanda na kidunia kuhusu matumizi sahihi yarasilimali maji yaliyopo ardhini kwa kuzingatia Lengo namba 6 la MaendeleoEndelevu (SDG 6) kwa ajili ya upatikanaji wa maji safi na salama kwa watu wote.QC 20230315DAFWA

Evaluation of carbon, nitrogen and phosphorus in disturbed and intact tropical coastal forest sites in Tanzania

International Journal of Plant & Soil Science, 2019; 27(1): 1-12This study investigated and established the variation of soil nitrogen, total carbon and phosphorus across closed forest; crop-agriculture and livestock disturbed sites. The study provides useful information for local management strategies. It sets initial basic data on the soil status of Uzigua Forest Reserve after 50 years of crop-agriculture and livestock grazing pressure. Forty-seven (50 m × 50 m) quadrats were established on each land uses for soil samples collection. Total nitrogen was analyzed by Kjeldahl acid-digestion, total carbon by the Walkley-Black procedures and phosphorus by Bray-II method. The mean values (percentage) were nitrogen = 16.07 ± 0.34, 1.75 ± 0.25, 6.5 ± 0.20; carbon =14.48 ± 0.23, 11.81 ± 0.13, 12.24 ± 0.30; phosphorus =14.12 ± 6.57, 17.74 ± 3.96, and 13.31± 2.86 for closed forest; agriculture disturbed and grazed sites respectively. There was a slightly lower amount of total carbon on crop agriculture disturbed sites than on thelivestock grazed land uses. Carbon-nitrogen ratio was higher in closed forests than in the disturbed sites. The relationship between forest degradation and soil nutrient status is an indication that the below-ground nutrient pools are mainly determined by activities, which disturb the above-ground components mainly vegetation. To restore soil fertility status, it is important to establish the management of the disturbed sites through restoration of vegetation and minimization of disturbances