Influence of solution chemistry on Cr(VI) reduction and complexation onto date-pits/tea-waste biomaterials

Tea waste (TW) and Date pits (DP) were investigated for their potential to remove toxic Cr(VI) ions from aqueous solution. Investigations showed that the majority of the bound Cr(VI) ions were reduced to Cr(III) after biosorption at acidic conditions. The electrons for the reduction of Cr(VI) may have been donated from the TW and DP biomasses. The experimental data obtained for Cr(VI)-TW and Cr(VI)-DP at different solution temperatures indicate a multilayer type biosorption, which explains why the Sips isotherm accurately represents the experimental data obtained in this study. The Sips maximum biosorption capacities of Cr(VI) onto TW and DP were 5.768 and 3.199 mmol/g at 333 K, respectively, which is comparatively superior to most other low-cost biomaterials. Fourier transform infrared spectroscopic analysis of the metal loaded biosorbents confirmed the participation of -COOH, -NH and O-CH groups in the reduction and complexation of chromium. Thermodynamic parameters demonstrated that the biosorption of Cr(VI) onto TW and DP biomass was endothermic, spontaneous and feasible at 303-333 K. The results evidently indicated that tea waste and date pits would be suitable biosorbents for Cr(VI) in wastewater under specific conditions.

Dilute phosphoric acid-catalysed hydrolysis of municipal bio-waste wood shavings using autoclave parr reactor system

The visibility of using municipal bio-waste, wood shavings, as a potential feedstock for ethanol production was investigated. Dilute acid hydrolysis of wood shavings with H3PO4 was undertaken in autoclave parr reactor. A combined severity factor (CSF) was used to integrate the effects of hydrolysis times, temperature and acid concentration into a single variable. Xylose concentration reached a maximum value of 17 g/100 g dry mass corresponding to a yield of 100% at the best identified conditions of 2.5 wt.% H3PO4, 175 degrees C and 10 min reaction time corresponding to a CSF of 1.9. However, for glucose, an average yield of 30% was obtained at 5 wt.% H3PO4, 200 degrees C and 10 min. Xylose production increased with increasing temperature and acid concentration, but its transformation to the degradation product furfural was also catalysed by those factors. The maximum furfural formed was 3 g/100 g dry mass, corresponding to the 24% yield. (C) 2011 Elsevier Ltd. All rights reserved.

Fermentable sugars recovery from lignocellulosic waste-newspaper by catalytic hydrolysis

The urgent need for alternative renewable energies to supplement petroleum-based fuels and the reduction of landfill sites for disposal of solid wastes makes it increasingly attractive to produce inexpensive biofuels from the organic fraction of the municipal solid waste. Therefore, municipal waste in the form of newspaper was investigated as a potential feedstock for fermentable sugars production. Hydrolysis of newspaper by dilute phosphoric acid was carried out in autoclave Parr reactor, where reactor temperature and acid concentration were examined. Xylose concentration reached a maximum value of 14 g/100 g dry mass corresponding to a yield of 94% at the best identified conditions of 2.5 wt% HPO, 135°C, 120 min reaction time, and at 2.5 wt% HPO, 150°C, and 60 min reaction time. For glucose, an average yield of 26% was obtained at 2.5 wt% HPO, 200°C, and 30 min. Furfural and 5-hydroxymethylfurfural (HMF) formation was clearly affected by reaction temperature, where the higher the temperature the higher the formation rate. The maximum furfural formed was an average of 3 g/100 g dry mass, corresponding to a yield of 28%. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the two-fraction models. It was found for both models that the kinetic constants (K) depend on the acid concentration and temperature. The degradation of HMF to levulinic acid is faster than the degradation of furfural to formic acid. Also, the degradation rate is higher than the formation rate for both inhibitors when degradation is observed.

Hip protectors to prevent hip fractures - a waste of time and money?

Abstract:
Background: An estimated 30-60% of older
adults fall every year and about 1% of falls result in a hip fracture. Hip fracture is a serious and growing problem, with a 3-10 fold rise in worldwide incidence predicted by 2050 (Gullberg, et al 1997). Hip protectors are underwear with built in protection for the greater trochanter. They are designed to prevent hip fractures by dispersing or absorbing the force of a fall. Trials
published to 2001 were broadly supportive of
the effectiveness of hip protectors, and this
was reflected in a Cochrane review in 2000.
However, earlier trials were methodologically
flawed and subsequent trials have not demonstrated effectiveness. The most recent Cochrane review describes only a marginal benefit (Parker et al, 2005).
Review and Discussion: This presentation
evaluates the current evidence for the use
of hip protectors and discusses the use of
that evidence by manufacturers, suppliers,
professional groups and guideline developers.
Interestingly, despite the limitations of the
evidence base, most advice has been broadly
supportive. Reasons for this are proposed
and discussed in the context of a critique of
evidence-based healthcare. protectors. However, the available evidence can be used in different ways and for different purposes by those with an interest in promoting
the use of hip protectors. A conservative
approach is warranted, where, if we cannot
demonstrate that hip protectors work, we
presume that they do not. This presentation will be of use to practitioners wanting to evaluate the evidence base for hip protectors (and other recommended interventions) on behalf of clients. It will also be of interest to policy makers who must assess the claims made for health care technologies as part of the decisionmaking process.
Recommended reading:
Gullberg B, Johnell O, Kanis JA (1997) Worldwide
projections for hip fracture. Osteoporos
Int. 7(5):407-13 .
Parker MJ, Gillespie WJ, Gillespie LD (2005) Hip
protectors for preventing hip fractures in older
people. The Cochrane Database of Systematic
Reviews Issue 3. Art. No.: CD001255.pub3. DOI:
10.1002/14651858.CD001255.pub3.

Local materials for building houses: laterite valorization in Africa

This paper presents the preliminary results of geological and geomechanical studies on the laterite stone exploited at Dano quarry in Burkina Faso. The field work described the geological structure of quarry sites and their environment to determine the rocks alteration and the links between the bedrock and lateritic material. Physic-mechanical properties have been studied for assessing the potentiality of this material for lightweight housing, to be completed with thermal and environmental considerations. Some social and economic evaluations are in progress in order to foster its utilization under local conditions.

Local materials for building houses: Laterite valorization in Africa

This paper presents the preliminary results of geological and geomechanical studies on the laterite stone exploited at Dano quarry in Burkina Faso. The field work described the geological structure of quarry sites and their environment to determine the rocks alteration and the links between the bedrock and lateritic material. Physic-mechanical properties have been studied for assessing the potentiality of this material for lightweight housing, to be completed with thermal and environmental considerations. Some social and economic evaluations are in progress in order to foster its utilization under local conditions. © (2014) Trans Tech Publications, Switzerland.

Development of a value-added soil conditioner from high shear co-granulation of organic waste and limestone powder

This paper reports on a technical feasibility study of the production of organo-mineral fertiliser from the co-granulation of limestone powders with tea waste. The results from this preliminary study show that the co-granulation of tea waste provided an alternative method of waste recovery, as it converts the waste into a value-added product. Fertiliser granules were successfully produced from various compositions of limestone and tea waste. The effect of tea waste concentration on granule strength was analysed; the granule strength
was in the range 0.2 to 1.8 MPa depending on powder composition; increasing the tea waste mass fraction resulted in a reduction in granule strength.Varying the teawaste to limestone ratio also influenced the compressibility of the granules; the granules compressibility increased with increasing tea waste mass fraction. It was further found that increasing the mass fraction of tea waste in the binary mixture of powder reduced the granule median size of the batch.

Waste Management and Sustainability during the Design Phase of a Construction Project: A Qualitative Review

Waste management and sustainability are two core underlying philosophies that the construction sector must acknowledge and implement; however, this can prove difficult and time consuming. To this end, the aim of this paper is to examine waste management strategies and the possible benefits, advantages and disadvantages to their introduction and use, while also to examine any inter-relationship with sustainability, particularly at the design stage. The purpose of this paper is to gather, examine and review published works and investigate factors which influence economic decisions at the design phase of a construction project. In addressing this aim, a three tiered sequential research approach is adopted; in-depth literature review, interviews/focus groups and qualitative analysis. The resulting data is analyzed, discussed, with potential conclusions identified; paying particular attention to implications for practice within architectural firms. This research is of importance, particularly to the architectural sector, as it can add to the industry’s understanding of the design process, while also considering the application and integration of waste management into the design procedure. Results indicate that the researched topic had many advantages but also had inherent disadvantages. It was found that the potential advantages outweighed disadvantages, but uptake within industry was still slow and that better promotion and their benefits to; sustainability, the environment, society and the industry were required.

An overview of waste crime, its characteristics, and the vulnerability of the EU waste sector

While waste is increasingly viewed as a resource to be globally traded, increased regulatory control on waste across Europe has created the conditions where waste crime now operates alongside a legitimate waste sector. Waste crime,is an environmental crime and a form of white-collar crime, which exploits the physical characteristics of waste, the complexity of the collection and downstream infrastructure, and the market opportunities for profit. This paper highlights some of the factors which make the waste sector vulnerable to waste crime. These factors include new legislation and its weak regulatory enforcement, the economics of waste treatment, where legal and safe treatment of waste can be more expensive than illegal operations, the complexity of the waste sector and the different actors who can have some involvement, directly or indirectly, in the movement of illegal wastes, and finally that waste can be hidden or disguised and creates an opportunity for illegal businesses to operate alongside legitimate waste operators. The study also considers waste crime from the perspective of particular waste streams that are often associated with illegal shipment or through illegal treatment and disposal. For each, the nature of the crime which occurs is shown to differ, but for each, vulnerabilities to waste crime are evident. The paper also describes some approaches which can be adopted by regulators and those involved in developing new legislation for identifying where opportunities for waste crime occurs and how to prevent it.