Chroom sanering van leerlooierijen

The use of leather articles is growing worldwide from time to time. Due to this leather tanning becomes an important manufactoring for economy of developing. However leather tanning causes environmental and human health problems due to the chromium mainly used for the tanning process. The main aim of this project is to reduce chromium pollution to the environment from tanneries. The study will focus on reducing the amount of chromium discharged from tanneries by increasing the chromium uptake on the leather. By applying ultrasound technology during chrome tanning process the diffusion problem of the tanning process by reducing the mass transfer boundary and increasind diffusion. This will also has an economical benefit by decreasing the cost to be invested on chromium and increasing the quality of the leather product as well. Moreover, the project is also focused on finding a low cost, locally available adsorbent to remove the possibly oxidized chromium leftover from the waste stream by using ultrasound.Table of Contents Acknowledgement V Abstract VII Samenvatting XI 1. Introduction - 1 - 1.1 History of leather making - 1 - 1.2 Current leather making in Ethiopia and its challenges - 1 - 1.2.1 Chromium uptake - 2 - 1.2.2 Chromium removal - 3 - 1.3 Research objectives - 4 - 1.4 Thesis outline - 5 - 1.5 References - 6 - 2. A review of chromium remediation options for leather tanneries - 9 - Abstract - 9 - 2.1 Introduction - 10 - 2.2 The leather tanning process - 11 - 2.2.1 Pre-tanning [beamhouse operation] - 12 - 2.2.2 Tanning [Treatment process] - 14 - 2.2.3 Finishing - 16 - 2.3 Chromium and chrome tanning chemistry - 17 - 2.3.1 Chromium chemistry - 17 - 2.3.2 Chrome tanning chemistry - 21 - 2.4 Chromium remediation options - 23 - 2.4.1 Source reduction - 23 - 2.4.2 Toxicity reduction - 27 - 2.4.3 Recovery and separation - 30 - 2.5 Conclusion - 44 - 2.6 References - 45 - 3. Impact of tannery effluent on the self-purification capacity and biodiversity level of a river - 59 - Abstract - 59 - 3.1 Introduction - 60 - 3.2 Method and Materials - 61 - 3.3 Results and Discussion - 64 - 3.4 Conclusion - 68 - 3.5 References - 69 - 4. Ultrasound assisted chrome tanning: towards a clean leather production technology - 73 - Abstract - 73 - 4.1 Introduction - 74 - 4.2 Material and Methods - 77 - 4.2.1 Experimental setup - 77 - 4.2.2 Analysis methods - 79 - 4.3 Results and discussion - 81 - 4.3.1 US before tanning - 81 - 4.3.2 US during tanning - 87 - 4.4 Conclusion - 93 - 4.5 References - 93 - 5. Effect of ultrasound on adsorption-desorption efficiency of Cr(VI) from skin powder: from a waste treatment to a clean production technology - 97 - Abstract - 97 - 5.1 Introduction - 98 - 5.2 Materials and methods - 101 - 5.2.1 Adsorbent preparation - 101 - 5.2.2 Experimental setup - 102 - 5.2.3 Adsorbent characterization - 105 - 5.3 Result and discussion - 111 - 5.3.1 Characterization of the adsorbents - 111 - 5.3.2 Effect of pH - 114 - 5.3.3 Effect of contact time - 116 - 5.3.4 Effect of adsorbent dose - 117 - 5.3.5 Adsorption isotherm and kinetic models - 118 - 5.4 Test using synthetic wastewater - 125 - 5.5 Desorption study - 127 - 5.6 Conclusion - 132 - 5.7 References - 133 - 6. Cost-benefit analysis on the use of ultrasound in chrome tanning and chromium remediation processes - 141 - Abstract - 141 - 6.1 Introduction - 142 - 6.2 Method and materials - 144 - 6.2.1 Process description - 144 - 6.2.2 US in chrome tanning - 144 - 6.2.3 US in adsorption - 144 - 6.2.4 Measurement and indicators - 145 - Direct costs and benefits - 145 - Indirect costs and benefits - 145 - 6.3 Result and discussion - 147 - 6.3.1 Costs and benefits of US tanning - 147 - 6.3.2 Costs and benefits of US adsorption - 152 - 6.4 Conclusion - 155 - 6.5 References - 155 - 7. Conclusions and future perspectives - 157 - 7.1 Conclusions - 157 - 7.2 Future perspectives - 161 - List of publications and CV - 163 -status: publishe