Pengaruh Kecepatan Pengadukan dan Tekanan Pemompaan pada Kombinasi Proses Koagulasi dan Membran Ultrafiltrasi dalam Pengolahan Limbah Cair Industri Karet

Laboratory scale studies have been conducted to assess the effect of stirring speed and pressure pumping on a combination of coagulation and ultrafiltration membranes in crumb rubber wastewater treatment. Prior to treatment, neutralization of wastewater in advance using 0.1 N NaOH to obtain a pH neutral in wastewater. The function of neutralization is to optimize the performance of the coagulation process. wastewater which has been neutralized then carried coagulation-flocculation process using a coagulant PAC with a concentration of 100 ppm. Coagulation process is done by varying the stirring speed of 100 rpm, 200 rpm and 300 rpm for 5 minutes and continued with the process of flocculation with a stirring speed of 60 rpm for 10 minutes. Wastewater then allowed to sedimentation for 30 minutes to precipitate the floc-floc had formed. Then the wastewater is separated from the sediment / floc using filter paper. The result showed that the maximum stirring speed in the coagulation process to reduce pollutant load in wastewater rubber is 200 rpm. Wastewater has been coagulated with stirring speed of 200 rpm and then fed into the ultrafiltration membranes with a variation of pressure of 1 bar, 2 bar and 3 bar. The maximum operating pressure ultrafiltration membranes to reduce the pollutant load in wastewater rubber is 3 bar. A combination of coagulation and ultrafiltration membrane able to reduce pollutant load in wastewater rubber with a value of BOD decline is 84.11%, COD is 84.17% , TSS is 95.40% and ammonia is 51.19%

Pengolahan Limbah Cair Industri Karet dengan Kombinasi Proses Pretreatment dan Membran Ultrafiltrasi

The development of new industries can increase prosperity for the people, but had a negative impact on the environment. Industries that produce waste one of them is the rubber industry. Rubber industries produce wastewater containing organic compounds are relatively high. Rubber industrial wastewater treatment needs to be done first in order to tackle pollution. This study was conducted to test the effectiveness and influence of pretreatment process and ultrafiltration membranes in wastewater treatment process of the rubber industry. Wastewater rubber which has been neutralized, in coagulation using coagulant aluminum sulfate (150 mg/l; 200 mg/l; 250 mg/l) with stirring speed of 200 rpm for 5 minutes and 60 rpm for 15 minutes, then allowed to stand for 30 minutes. Waste water sample is filtered then ultrafiltration with variations in pumping pressure (1 bar, 1,5 bar, 2 bar). The results showed the coagulation process is effective at a dose of coagulant Aluminum Sulfate 250 mg/l is 58,71% of BOD5, 59,04% of COD, 35,71% of TSS and 25% of ammonia. The percentage of waste generated rejection increases with increasing pumping pressure of 1 bar to 2 bar. The rejection percentage is 67,30% of BOD5, 67,19% of COD, 88,15% of TSS and 35,71% of ammonia at 2 bar

FWHM Dimentional Analysis From Scattered Light Intensity Profile for Dry Rubber Content Determination in Natural Rubber

Dry Rubber Content (DRC) describes a rubber particle percentage in natural rubber latex. In this paper, the relation between forward light scattering profiles of natural latex and rubber contents is reported for dry rubber content latex. The profile, characterized by Full Width at Half Maximum (FWHM), is increasing linearly with respect to rubber content. The measurement was performed immediately after latex being tapped with necessary addition of acetic acid. This addition was meant to prevent latex coagulation. There is a high linear correlation between DRC and FWHM of both domain: one and two dimension. This is indicated by correlation factor which are higher than 0.9 for both of domains and sufficient in DRC determination

The interaction of polymer surfaces with blood

Some general aspects of the interaction of foreign materials with blood are summarized. The role of protein adsorption in this interaction is briefly discussed. In an attempt to produce more stable antithrombogenic surface coatings than the well-known heparin-bonded surfaces, a method is described in which a high-molecular-weight polyelectrolyte is bound to polymer surfaces. In vitro experiments carried out with freshly drawn human blood show a reduced platelet adhesion on such surfaces

Evaluation of low frequency tapping systems with stimulation on hevea in traditional area Cambodia

In Cambodia, the common tapping system which was widely adopted by smallholders and agro-industry plantations was S/2 d3 for downward tapping and S/4 d3 for upward tapping. However, under the decline of rubber price and increasing labor shortage, the application of low frequency tapping systems (LFT) may be a choice to solve these problems. Hence, different low frequency tapping systems were tested in traditional area of Cambodia. An experiment was established using seven-year old rubber trees of RRIM 600 clone at the Cambodian Rubber Research Station located in Tbong Khmum province. The experimental design was Randomized Complete Block Design with four treatments: T0: S/2 d37d/7 ET 2.5% 4/y, T1: S/2 d4 7d/7 ET 2.5% 5/y, T2: S/2 d5 7d/7 ET 3.3% 6/y and T3: S/2 d6 7d/7 ET 3.3 % 10/y comprising three replications (12 elementary plots). There were 120 trees per treatment in each elementary plot. After 3 years of tapping, LFT system S/2 d6 with Ethephon application (T3) provided the highest dry rubber yield per tree per tapping (g/t/t) but the lowest yield in gram per tree (g/t) and kilogram per hectare (kg/ha). As compared to d3, LFT systems (d4, d5 and d6) caused dry rubber yield loss in kg/ha by respectively 3, 9 and 11% but resulted in increased labor productivity (g/t/t) by respectively 11, 28 and 48%. Therefore, the increase in labor productivity (g/t/t) was higher than the loss in land productivity (kg/ha). Girth increment was not significantly different between treatments. Sucrose and reduced thiol contents of all treatments were not significantly different but inorganic phosphorus content was significantly different depending on the tapping system. Tapping panel dryness was similar for all treatments after three years of tapping

Synthesis and properties of composites of starch and chemically modified natural rubber

A means is developed for forming polysaccharide-based composites with useful material properties through use of unmodified and chemically modified natural rubber latex (NRL). Starch was used as a model for polysaccharides. The NRL was modified by grafting with dimethylaminoethyl methacrylate (DMAEMA) to form a latex with cationic water-soluble polymeric “hairs” of polyDMAEMA, which should form hydrogen bonds with starch. Starch solutions, containing 20% glycerol as a film-forming aid, and the modified NRL were mixed and films allowed to form. The unmodified latex acted only as filler in the starch films, but with modified NRL, the mechanical properties of the films were significantly altered. The elastic modulus was greatly decreased and strain at break greatly increased. The glass transition temperature increased from –48°C to –32°C, suggesting significant compatibilization. Freeze-fracture TEM micrographs indicate strong interactions between the surface of the modified NRL and starch. The polyDMAEMA chains are more hydrophilic than the starch, and the addition of grafted latex results in a 20° drop of the water contact angle of the formed film, and a 25% increase of the water absorption compared to the native starch; with unmodified NRL, the opposite effect was observed

Effect of cell density on thrombin binding to a specific site on bovine vascular endothelial cells.

We studied thrombin binding to proliferating and confluent endothelial cells derived from bovine vascular endothelium. [125]thrombin was incubated with nonconfluent or confluent endothelial cells and both the total amount bound and the amount linked in a 77,000-dalton thrombin-cell complex were determined. Approximately 230,000 molecules of thrombin bound per cell in nonconfluent cultures compared to 12,800 molecules per cell in confluent cultures. Approximately 67,7000 thrombin molecules were bound in an apparently covalent complex, Mr = 77,000, with each cell in sparse cultures, whereas only 4,600 thrombin molecules per cell were bound in this complex with confluent cultures. Similar studies with [125I]thrombin and endothelial cells derived from bovine cornea revealed no difference either in the total amount of thrombin bound or in the amount bound in the 77,000-dalton complex using sparse or confluent cultures. When confluent vascular endothelial cultures were wounded, additional cellular binding sites for the 77,000-dalton complex with thrombin appeared within 24 h. A 237% increase in the amount of thrombin bound to these sites was induced by a wound which resulted in a 20% decrease in cell number in the monolayer. There was no significant increase in thrombin binding to other cellular sites at 24 h. These experiments provide evidence that the first change in thrombin binding after injury is an increase in the cellular sites involved in the 77,000-dalton complex, and suggest that thrombin binding to endothelial cells may be important in the vascular response to injury

Biodegradable hollow fibres for the controlled release of hormones

Poly(l-lactide), (PLLA), hollow fibres were prepared using a dry-wet phase inversion spinning process. The effect of several spinning parameters (i.e. bore medium flow rate, spinning dope extrusion rate, fibre take-up rate, and spinning height) on the hollow fibre dimensions is reported. The use of several spinning systems (i.e. different solvent/non-solvent pairs with or without additive) resulted in PLLA hollow fibres with varying asymmetric membrane structures, i.e. a porous matrix covered by an internal and external skin varying from very thick and dense to very thin and porous. Some of the differences in membrane structure were qualitatively explained on the basis of a model developed by Reuvers [52] for the formation of flat-sheet membranes by immersion precipitation. Release experiments were carried out using PLLA hollow fibres filled with a 25 wt.% dispersion of micronized 3H-levonorgestrel in castor oil, and a receiving fluid consisting of 40 wt.% aqueous ethanol. The hollow fibre levonorgestrel release rates were found to be dependent on the membrane structure of the hollow fibre wall. For the different hollow fibre samples, zero-order levonorgestrel release rates were found, in the range of 0.1–10 μg/cm/day. Possible release mechanisms are discussed. Preliminary in vivo (rabbit) release experiments showed that constant levonorgestrel blood plasma levels could be obtained for a period up to 210 days. It is concluded that the new biodegradable hollow fibre reservoir device shows very promising properties for possible application as a long-acting contraceptive delivery system